sbc overheating. 650hp rated aluminum radiator

[shtterbug8]

having overheat problems...i think.

when drivng the truck runs a nice 150-175degress.

but if i get stuck at a light it has reached as high as 220degrees!

radiator is all aluminum bolt in style for the 1951 chevy truck. its rrated for 650hp engine even though my 350 sbc is stock.

im not running a tstat. radiator is water only. hoses are all new. non collasped.

running an electric fan covering the entire radiator span as a pusher. i have no room to mount as puller.

what can i do guys?

could it be my timing? the truck starts right up with slight touch of the key iginition.

could it be the liquids? should i go with a 50/50 mixture? or is there anther liquid out there i could use to help cool it?

my spark plugs are the original ones when i first bought the engine....should i replace now?

could it be the place i mounted the temp sending unit? the unit that came with my new guages was huge and would only fit onto my water pump.

[henry29]

I've run plenty of cars with straight water and no t-stat, never any problems,

Could be the timming, could be running lean, could be a small head gasket leak, could be bored over a little to far.

I have plenty of room in my 48 chevy truck with a 350 for a fan.

What radiator do you have?

[divco13]

Put a 185 T stat. At idle the water is moving to fast to transfer the BTU's (heat ) to the Alum Rad. At speed the supply flow of cool ambient air is plentiful.
Needs restriction to slow down the water, in order to transfer the heat out of the water.
And course a well made shroud is the ticket.
My 502 run's a 185 stat, only very hot day's it get's to 200 degree's

[Mr48chev]

I'm thinking it is an airflow issue at low speeds. If the temp drops as soon as the truck is moving at any speed at all and then goes up when you slow down to a crawl or stop at an idle the pusher fan just flat isn't pushing enough air.

If you have the sending unit in the water pump rather than the block, head or manifold you are measuring the temp of the coolant returning from the radiator and not what it is in the block or leaving the block.

And yes I would run a 50./50 mix of quality antifreeze. It may not get the temp down any but it helps prevent crud buildup in the cooling system. This day in age it is more than counterproductive to run straight water. It is easier to clean up if the radiator cap pukes it out though.

If you don't put a thermostat in it try putting the hulled out washer part of a thermostat in it. I've done that on my own rigs a number of times and it gives just enough restriction to slow the flow down so it can transfer the heat both ways. You not only have to transfer the heat from the block and heads to the engine but from the radiator to the atmosphere.

[shtterbug8]

its a no name radiator off ebay....here are the specs

Year: 1951-1954
Core Size: 21-1/2"×17-1/8"×2-1/2" 3 row
Inlet/outlet: 38/45mm
overall size: 22-3/8"×21-7/8"×3"

<

[Truckedup]

Yes,airflow...heating up in traffic means more fan needed..or better fan..or shroud .
Think about the 650 HP rating on the radiator..How much power is your engine developing when stopped in traffic?

[Steves32]

How many amps is that electric fan?
Most off brand fans are liars when quoting CFM.
Electric fans work better as a puller- on engine side of radiator.
Make sure fan is spinning in correct direction- you can verify w/ a piece of paper. Put a thermostat in it.

[shtterbug8]

its a curved blade fan. i believe its rated for 2200 cfm. im not sure on the amps. i might have to bust out the meter.185 stat then? or less?

yes its spinning the right direction.

[shtterbug8]

i looked up online parts place. they have 160 degree stat. im not sure what i should get. what yall think? im not running a heater. summer only truck.

[Old Iron Nut]

Is the problem new (mechanical failure)? I used to have this issue with my pickup, 160 degree t-stat install, puller fan, and new water pump fixed it.

[squirrel]

Core Size: 21-1/2"×17-1/8"

I have a 650 hp engine, and my radiator core is a lot bigger than that....and it gets up to 220 or so in traffic, with a big well shrouded clutch fan. The important thing is that it never boils over.

btw 220 isn't anything to worry about, but running at 150 is kind of cold. I'd put a 180 thermostat in it, along with some antifreeze, and a pressure cap that is recommended for the radiator (probably 13-16 psi), and see how it does.

Seems that the last thing some folks think about when doing an engine swap, is leaving room for a fan. It's one of the first things I think of.

[need louvers ?]

A thermostat would be the very first place I would start. I can't imagine why you would run without one. The fan mounted in a pusher capacity would go away as quickly as possible as well in favor of a mechanical with a shroud. A thermostaic clutch fan is the only way to fly. Two problems with the electric as you have it now are that a fan is only partially as efficient mounted in a pusher manner, and it also partially blocks incoming airflow. Bad deal both ways around it. Down here in the heat, you won't find an electric fan other than OEM stuff that will last more than a summer or so, period, so most of us here in the desert just say no...
My car out fitted the way I suggest above with a 430 horse aluminum headed 360 will sit in traffic on a 118 degree day with the A/C on and never go above 195 or so.

[shtterbug8]

the radiator cap that is on the radiator is the one that came with it. the radiator has not yet overflowed/boiled over. i think i heard it whistle though....not sure.

i guess you can say the problem is new. ive only put 140 miles on the truck so far....engine and frame is from a 92 silverado. body is 51 chevy. was a really good fit. just seeing that 220degrees kinda concerned me.

how hot is to hot for a sbc?

[Old Iron Nut]

Newer models run pretty warm, 220 isnt dangerously high unless your motor is sensitive to detonation

[groundpounder]

Most of the time it's either water pump speed or ( water speed) through the radiator core. If the water flows to fast there isn't enough time to cool the water!..try a 5/8 restrictor in the thermostat housing or thermostat...any one! Try that first! 50/50 mix...or even Water Wetter. I've seen and built 800+ Hp dirt late model engines (4 blade GM Fan and no shroud) that run at 180 no problem. At best hp temps 210/230 WT and 240/260 Oil Temp. Look at your pulley ratios next....good luck!

[tfeverfred]

Strap a Ford Taurus fan on that sucker.

[mustang6147]

If your runnin a 92 fuel injected engine, I cant believe you can get it to run at 150. 220 is pretty normal. If its an LT1 then I am even more shocked.

I dont think the injection ( if it is) comes out, and into a running loop until over 200. You are supposed to have a 195 thermostat in it.

A thermo/ antifreeze, and if you want water wetter should be good, if you have a good fan.

I do want to ask, who you bought the radiator off of?? I am lookin at one out of Michigan, 586 area code I think... Is that the same place?


TCI makes a chip, otherwise your fighting you computer, which will continue to try to heat the engine ... over 195

[GassersGarage]

I had to previous cars that would run hot and this is how I cured the problem.
1. '51 Ford Gasser - 421 Pontiac, no thermostat and vacuum advance wasn't hooked up. The car would run 215. I added a 160 thermostat with bleed holes, hooked vacuum advance to manifold vacuum. Car ran at 180 after that.
2. '52 Chevy - stock 350, car ran at 180 but in traffic, would get to 210 and wouldn't come down, even if traffic moved. Mechanical fan pulled great. Radiator was flushed and a 160 thermostat was installed. Still ran warm until I got a new distributor. The mechanical advance was frozen and the car was always running retarded.

[Waddayacare]

One word......

FAN!

Ditch that electric B.S. and install a good 17" or 18" Flex-a-lite mechanical flex fan.

[VonKool13]

Like mentioned use a shroud and a t-stat. 25/75 wont hurt. Helps keep ur water pump lubed properly.

[pug man]

Sounds like the water is flowing through too fast. Take a thermostat and gut it and then just put the part of the thermostat with nothing in the center and try that. It should slow the water down enough so that it stays cool.... Good luck

[shadams]

My 85 4x4 with a 350 runs 220 all the time, sometimes 230 and I have thrown everything but the kitchen sink at it and nothing has changed. I gave up and just drive it and it runs like a bat out of hell. love it..

[rd martin]

you mite want to think about cooling components 2 5/8s thick electric puller fan, 2800 cfm at idle, works great put 3 in diff cars, no problems, 180 degree them, 13 lb cap. 40 ford coupe, small grille not alot of air flow, runs 190 195 with air on, 94 degree day at idle. fan sold by walker radiator. it works.

[shtterbug8]

engine was switched over to a 2bbl gas. in the future it will be a 4bbl.

[Avgas]

If car companies didn't need to install thermostats in there engines then why do they fit them? My 2c's worth is a 160 degree thermostat for a start then drive your ride and see what happens next! Beware of Chinese shit on e bay! Wayne

[jamesdmikesell]

dont use water use coolant water boiles at 212 a 50 \50 blend should be good to 240 if the cooling system is good (ie hoses, radiator, and cap) try this before you spend a lot of money

[shtterbug8]

new stat...160
anti freeze added....

now i can rule out something....

i watched the temp guage like a hawk. rose all the way to 225 then dropped to 160. then rose all the way up to 220 wth. is this right? or is my temp guage wronge?

while watching the temp g. i keep placing my hand on the radiator to see how hot it was getting. didnt get hot til the temp guage dropped the first time. so i guess the stat opened up.
i temp guage sending unit is located on the water pump itself. is this bad?

[unkledaddy]

Are you running a hi-flow water pump? Have you used a infrared laser temp gun to see what the actual temp of your engine is? Are you satisfied that the gauge is reading properly?

You can buy a cheap mechanical temp gauge for $15.00. Boil it in some water with a candy thermometer to make sure it's accurate, and install it on your motor. Then you'll
know what's what.

[choprods]

is your guage at all accurate? Lots of recently made ones are not....
BTW 220 is actually OK in a Chevy engine newer than '90......
Take a cooking thermometer and stick it in the core of radiator and compare the readings of it and your guage-you may be suprised

[wingedexpress]

Put the sending unit in the head.

[squirrel]

Put the sending unit in the head, or in the intake manifold next to the thermostat. The head location will get hotter, the intake location will tell you how hot the coolant is when it's ready to go to the radiator to get cooled off.

What gage is it?

220 is ok on engines older than the 90s too....they're pretty much the same engines, after all.

[tex1935]

If the fan was set up to push and it was installed to pull, The first thing you need to do is flip the blades around on the motor, Second thing you need to do is switch the wires going to the fan. The clues you gave indicate temp ok at running down road . temp high at idle or in traffic. Air flow is the problem. texs1935

[tiredford]

[QUOTE=shtterbug8;7895780]new stat...160
anti freeze added....

now i can rule out something....

i watched the temp guage like a hawk. rose all the way to 225 then dropped to 160. then rose all the way up to 220 wth. is this right? or is my temp guage wronge?
__________________________________________________
This happened to me once on a Ford. The stat was in backwards, the hot water on the engine side couldnt get to the temp thingy, when the rad water finally got hot enough to open the stat, water gushed in and the temp dropped 50 degrees.

[n847]

do you have any pics of the set up is the rad inlet the highest point in the system, make sure theres no air in the system!

Not that I think your stupid but is the fan blowing the correct direction?

[ELpolacko]

Originally Posted by divco13

...the water is moving to fast to transfer the BTU's (heat ) to the Alum Rad...
Needs restriction to slow down the water, in order to transfer the heat out of the water...

Originally Posted by groundpounder

... the water flows to fast there isn't enough time to cool the water!....

Originally Posted by pug man

Sounds like the water is flowing through too fast. ...

Never EVER have I solved an overheat problem by slowing anything down. NEVER!

The OP's issue is a small radiator and insufficient airflow at low speeds. 190-210 with a 16 psi radiator cap is normal. 50/50 mix of modern anti-freeze and water is all you need, the rest of it is snake-oil.

[zman]

If that fan is a Zirgo it's from the beloved Hoffman groups and not worth a dime. Piece of crap and the rating is utter bull. I'm thinking air flow at low speed is the issue,

[ELpolacko]

Originally Posted by zman

If that fan is a Zirgo it's from the beloved Hoffman groups and not worth a dime. Piece of crap and the rating is utter bull.

Quoted and emphasized for absolute truth!

------------------------------------------------------------------------------------------

Needlouvers and I experimented with a Zirgo (POS) fan supposedly rated at 2800 cfm or some other made up number. When it didn't perform close to half of the rated air flow, a call was made to them. They mentioned unrestricted airflow at 48 volts or something similar. So in other words, shit stained sales pitch.

[1971BB427]

I doubt the radiator size is too small. My radiator is a Griffin 16"x17"x3" with two 1" rows, and it cools my approx. 400hp 327 just fine with a 160 stat, and a dreaded pusher fan. I run right at 185-190 all the time, idling or at speed. My fan is the biggest, highest cfm I could find, and I think that is the difference.
I'd find a larger cfm fan so you're moving as much air when idling as you are moving down the road.

[need louvers ?]

Originally Posted by ELpolacko

Quoted and emphasized for absolute truth!

------------------------------------------------------------------------------------------

Needlouvers and I experimented with a Zirgo (POS) fan supposedly rated at 2800 cfm or some other made up number. When it didn't perform close to half of the rated air flow, a call was made to them. They mentioned unrestricted airflow at 48 volts or something similar. So in other words, shit stained sales pitch.

AND, absatively the reason I will never, never, never, never, never run an electric fan on a hot rod again!!! I don't know if Elpolacko remembers this, but that same summer saw me put three different fans in the Plymouth, all by different manufacturers, all died horrible deaths in the Phoenix heat in between 2 weeks and 2 months... Problem solved by going back to my big old fan clutch and Cadillac 7 blade fan and my shroud...

[Unkl Ian]

Originally Posted by shtterbug8

im not running a tstat. radiator is water only.
running an electric fan covering the entire radiator span as a pusher.

Run a 190 thermostat, antifreeze, and a good rad cap.

If that isn't enough, figure out how to put an OEM puller fan on back.

[shtterbug8]

wow....this is a crazy thread. lol. drove the truck over 45 miles today. drove great. at one point my gauge maxed out at 250....

the guages are omega kustom. the temp sending unit came with the guages but was freakin huge. the only plug i could find that was the correct size was located in the water pump top side. the fan i believe is doing just fine now on the cfm rating. almost all 17" fans are rated 1700-2200 cfms regardless of the brand or manufacturer. im not sure on the brand of mine. i can NOT install a fan on the back of the radiator because i have a little less than 2inches between the rad and the water pump pulley the thinnest fan i could find was a 2.5 inch fan. if i could run the original clutch fan i would. i love the clutch fans! but sadly i can not in this setup. i do believe the temp gauge is reading wronge and im not looking for a infared temp guage or some themometer to stick into the radiator fins.

thanks for the input guys!
also ive tried making the carb run richer and the truck just stumbles on itself. timing is also dead on. so i can rule those two out also.i will post pictures here in a few mintues of everything. thanks

[shtterbug8]

[squirrel]

Is that the sender that came with the gage? or is it some other sender? Gages need to be used with the correct sender, or they will read wrong. Anyways...where it is located is where the cool water from the radiator goes back into the engine. Which is not very helpful, assuming the gage is actually working right.

Is there any way to move the radiator forward a bit?

[vg62truck]

Simply put, the water needs to spend more time in the rad. If you do not want to run a thermostat, at least slow down the flow at the thermosatat housing. Use an old thermosat with the centre remove or a large washer. The cooling all happens in the rad, the coolant has to be there long enough for it to do its job

[bobscogin]

Originally Posted by groundpounder

If the water flows to fast there isn't enough time to cool the water!..

This has always puzzled me. If it's flowing too fast to transfer heat to the radiator, how come it wasn't flowing too fast to to allow heat transfer from the block and heads?

Bob

[shtterbug8]

Originally Posted by vg62truck

Simply put, the water needs to spend more time in the rad. If you do not want to run a thermostat, at least slow down the flow at the thermosatat housing. Use an old thermosat with the centre remove or a large washer. The cooling all happens in the rad, the coolant has to be there long enough for it to do its job

tstat was installed. its 160degree. i picked low temp since im not running a heater that way the engine will warm up faster when first started. inwhich it did just that.

[shtterbug8]

Originally Posted by squirrel

Is that the sender that came with the gage? or is it some other sender? Gages need to be used with the correct sender, or they will read wrong. Anyways...where it is located is where the cool water from the radiator goes back into the engine. Which is not very helpful, assuming the gage is actually working right.

Is there any way to move the radiator forward a bit?

yes its the sender that came with the guages. the radiator is installed in the factory location. i can not move foward any because of hood latch

[unkledaddy]

Check to make sure you're getting a good ground to the sender.
You didn't wrap the threads with Teflon tape did you?

[shtterbug8]

i dont know if it matters or not....i noticed when i turned on my cooling fans inside the cab on all my gauges moved about 1/4 one way or another. why would turning a fan on inside my cab to cool me mess with gauges that are not hooked up to them? could all this be because of bad grounds?

[unkledaddy]

Originally Posted by shtterbug8

could all this be because of bad grounds?

You betcha'! You can never have too many grounds.
Poor grounds are like gremlins.
Ground the sender and see what happens.

[shtterbug8]

how to i ground that temp unit then? that sounds kinda tricky. dang...i hate electrical work!!!!!!!!!!!!!!!!!!!!!!!!!!1

[studebaker46]

i am 64 and here is what my mentor told me at 16 if heatsup at idle it is an airflow prob. if it heatsup at speed it is coolantflow. now with that being said and reading your last post isuspect somthing is going on with the gauges. take it and have it checked at autozone or somewhere and have it checked with an infrared meter and see wher you are at at the very least you need t-stat and coolant tom

[unkledaddy]

Some type of alligator clip on one of the brass hex heads with wire run to a good ground.
It's just temporary.
Also refer to my post #28 to know for sure what the temp is.......like studebaker46 said.

[bobscogin]

Originally Posted by vg62truck

Simply put, the water needs to spend more time in the rad.

If you slow down circulation, how do you get it to spend more time in the radiator without also spending more time in the engine absorbing additional heat which increases the BTU load on the radiator?

Bob

[squirrel]

The gage/fan problem is probably due to voltage drop, not bad grounds. The cure might be to add a relay that gets it's power from the battery itself, not from the main wiring harness.

A voltmeter and some careful thinking should help you figure out what's going on. You can measure the voltage between the battery - terminal and the gage housing to test for ground problems, or between the battery + terminal and the gage power connector to see if the voltage is dropping too much. Anything more than a couple tenths of a volt is too much.

[shtterbug8]

any particular relay i should buy? i dont have any installed. now that this has been mentioned its got me wondering because every late model car ive ever seen has mutiple relays and such inwhich i know atleast one is for electric fans if equipped. what is currenly going thru my head is that the electric fan mounted on the radiator might not be recieving FULL voltage and running at lower CFM's and resulting in the overheat.....well. ive got alot of investgating to do. i will post my findings.

[bobscogin]

Originally Posted by shtterbug8

any particular relay i should buy?

One possibility; http://www.flex-a-lite.com/auto/31147-99936.pdf

Bob

[Pro Stock John]

How about a pic of your fan setup?

When it got to 250F on the gauge, was it popping out your overflow, what lb cap do you have on the radiator?

I have a 15-16 lb cap, 160 stat, old ass 26x17 radiator, single 16" puller 2.5 inches deep. Before it got to 90F here, I could be anywhere from 175 to 185F on the highway which was nice. Fan would come on in traffic at 205 or 210 (commanded), and take it down to 190F. Now my system cannot handle 90-95F in bumper to bumper traffic. Have seen 225-230F on gauge still was not popping but I just can't drive it like that makes me crazy loco. Once my car gets to 220F it cannot really get it back to 195, I'd have to drive a long time to cool it down.

I think I got my fan from http://www.the-fan-man.com/shop/-c-3...27a5b1a9181ada I have to find my receipt.

Had to mount it offset to avoid water pump.. Pic from a while ago, I'll try to take some better ones today:



I have 2-4" gaps all the way around my radiator.

I believe my solution is to get a new 2-row aluminum radiator (yep will paint it black), block off all air gaps on the side and bottom, and I really would like to run two electric fans if I have the room. But I also picked up a Lincoln Mark VIII e fan that's another popular swap fan.

Good luck I read all these overheating threads like crazy.

[choprods]

Have you used the external thermometer[turkey thermometer from a grocery store in the rad core] to see what temp you are =ACTUALLY= running at??? you may be perfectly cool and not be getting an accurate read from the guage....BTW never heard of the guage brand ,and in 40 plus years in the trade I wonder just how good are tose guages???
If Stewart Warners are even- not all- good.... then possibly?????

[40FordGuy]

I see no mention of what pressure radiator cap is being used...."220" degrees, with a 15 lb cap is well withing acceptable "limits".

Using a 50 / 50 mix, water / antifreeze, a 15 lb pressure cooling system will boil at 227 degrees. Each 1 psi will raise the boil point by 3 degrees, so in this case, the real boil point would be 257 degrees. 3 degrees X 15 lb = 45. Add that to the 212 degree boil point, and it becomes 257 degrees.

With those pressures and temperatures, car mfg stopped using "real" numbers on the temp gauges, because the buying public thought there was a problem.

When installing temp senders, the "bulb" must be as "submerged" in the coolant as possible; Using more than one thread adapter moves the bulb farther away from the coolant flow, and result in low readings.

Happy Roddin'
4TTRUK

[40FordGuy]

Oops....typo, the correct temp is 257,...NOT 227 !!!

4TTRUK

[40FordGuy]

I see no mention of what pressure radiator cap is being used...."220" degrees, with a 15 lb cap is well withing acceptable "limits".

Using a 50 / 50 mix, water / antifreeze, a 15 lb pressure cooling system will boil at 227 degrees. Each 1 psi will raise the boil point by 3 degrees, so in this case, the real boil point would be 257 degrees. 3 degrees X 15 lb = 45. Add that to the 212 degree boil point, and it becomes 257 degrees.

With those pressures and temperatures, car mfg stopped using "real" numbers on the temp gauges, because the buying public thought there was a problem.

When installing temp senders, the "bulb" must be as "submerged" in the coolant as possible; Using more than one thread adapter moves the bulb farther away from the coolant flow, and result in low readings.

Happy Roddin'
4TTRUK

[shtterbug8]

i have no idea what pressure cap is on the radiator. cap has no identification on it.

[mustang6147]

Ya know, I saw where the sensor is located, and thats just wrong in my opinion. It needs to be in the intake. I didnt read every post, cuz to me there kinda rodundant, so mine may be as well.

I also dont know, but if it where me, I would put a candy thermometer in the radiator, and compare your guage to the candy thermometer.

My gut is saying its where your sensor is located. Thats gotta be the hottest part right before the water goes through the radiator.

The electric fan switch should be in the front bank of the left head, and the guage should be in the intake near the water neck. Exception is the LT1 engine.

[squirrel]

Originally Posted by mustang6147

My gut is saying its where your sensor is located. Thats gotta be the hottest part right before the water goes through the radiator.

huh? The water pump is after the radiator, the water is as cool as it will get right there.

[1971BB427]

Yes, I had to move my temp pickup from the heads to the water pump when I swapped out the aluminum heads and went to the old camel humps with no hole for a stat. My temp readings are about 5 degrees lower at the water pump than they were at the heads before.

[mustang6147]

Ya I was just seein who knew that.........

well I guess thats my Blond moment.... WTH was I thinkin????

I have never seen a sensor in the water pump...It cant be accurate, and I also remember a few years ago, that style guage was plagued with fault....

I still say the candy Thermo might clear up, if it is really runnin that hot.

[Cadzook]

You can probably get by with using larger guage wires (14ga.) instead of complicating things with a relay. The wires I can see in the photo are pretty small. Also is the sender indeed that diameter or is it in a bushing? What is in the threaded bung next to the leaking thermostat housing? Can you put the sender there? You also have no overflow tank to catch the overflow as it heats and returns it to the radiator as it cools. Without it you will be fighting air in the cooling system and it will never work to it's potential.

~Alden

[mopar362000]

Vacuum advance should go to manifold vacum.will cool down engine.Jimmie King

[Hot Rod Chris]

I see u have messed with everything coolant wise, but never anything mentioned anbout your vacume advance.

Next, how much room exactly do you have between the pump and radiator? Have you tried bolting up a fan directly to the water pump?

[shtterbug8]

Originally Posted by mustang6147

Ya I was just seein who knew that.........

well I guess thats my Blond moment.... WTH was I thinkin????

I have never seen a sensor in the water pump...It cant be accurate, and I also remember a few years ago, that style guage was plagued with fault....

I still say the candy Thermo might clear up, if it is really runnin that hot.

so youve heard of the guages....? they are always forsale at the kyana swap meet

[mustang6147]

Originally Posted by shtterbug8

so youve heard of the guages....? they are always forsale at the kyana swap meet

Well I am not ignorant, although I expected alotta razzing from my one post. haha... We all have ones we would like to have back.

I will say though, I had the same problem in my Mustang, which I drag race. I put a bigger radiator in it. Problem solved. SHe runs 180 all day. no matter what the temp.

I have the same problem in my 40 GMC truck, I am gonna et a bigger radiator.

I never trust a guage with out double checking it, especially electric ones. The one you posted looked the same as the one at GoodGuys, that was faulty. They had a rash of bad ones. Thats why I suggested double checing it with a candy thermo.... SImple no cost check. ( just dont put it back in your wifes drawer) I made mine go away with all the cookie trays.

I havent said much on this post, although, I will say. My timing is set all in at 2500 in my 351 and she runs cool. SO to me timing may elevate cylinder temp, but not much for coolant temp if the system is adequit. And vacuum? I go with what ever the 40 street rod performs best with.

[Carnuba]

If it runs cool while dragging the weight of the truck, under load, when the engine makes the most heat then the radiator is ample. If it only runs hot at a dead stop, when the engine makes minimal heat then it's improper air flow thru that radiator

[40FordGuy]

If you have a mechanical temp guage of known accuracy, put it in, and see what readings you get...That'll resolve any question re; mismatched or inaccurate electric temp guage readings....

Definitely put the sender close to the t'stat, in the manifold, before it goes to the radiator.

4TTRUK

[unkledaddy]

Click here: Griffin Radiator - Radiator Tips

[aerorocket]

[QUOTE=ELpolacko;7896014]


Never EVER have I solved an overheat problem by slowing anything down. NEVER!

You are 100% correct. Some people should do some reading to understand how a radiator works.

[Morrisman]

Nobody has mentioned what sort of shrouding there is around the radiator. What is there to stop the hot air blowing out the back of the rad simply going back round front and through the rad again.

I had a buddy with a Nova race car, overheated all the time. He had a flip front on it, with nothing but the rad stood upright in the middle, no sheet metal, nothing.

Air was coming out the back of the rad and simply getting sucked back round through the fan, getting hotter all the time. When he was moving along it was okay as plenty of fresh air was forced into the loop, but at slow speed or stop the temp went through the roof.

You need to get the hot air out of the engine bay, not just blow air though the rad.

Or it can actually blow back through the outer areas of the rad, if the engine bay is pressuring up with air. Try driving around slow with the hood off for a little ways, see if there is any change. If it runs cooler then it is an airflow issue. Air flow out of the engine bay.



Of course if you do have all the full sheet metal sealing the rad all around then I'm talking shyte.

[40FordGuy]

Most radiator caps will have a marking on them,...usually looks like this example; 14#. If yours has no markings,..get a new one that IS marked, so you are working with a known fact; I would begin with a 15 lb cap.

Each lb will raise the boiling point of a 50 / 50 mix by 3 degrees.

Happy Roddin' 4TTRUK

[34toddster]

I'd spend the money to install a short water pump with a clutch fan and a shroud then go down the road

[shtterbug8]

Originally Posted by Morrisman

Nobody has mentioned what sort of shrouding there is around the radiator. What is there to stop the hot air blowing out the back of the rad simply going back round front and through the rad again.

I had a buddy with a Nova race car, overheated all the time. He had a flip front on it, with nothing but the rad stood upright in the middle, no sheet metal, nothing.

Air was coming out the back of the rad and simply getting sucked back round through the fan, getting hotter all the time. When he was moving along it was okay as plenty of fresh air was forced into the loop, but at slow speed or stop the temp went through the roof.

You need to get the hot air out of the engine bay, not just blow air though the rad.

Or it can actually blow back through the outer areas of the rad, if the engine bay is pressuring up with air. Try driving around slow with the hood off for a little ways, see if there is any change. If it runs cooler then it is an airflow issue. Air flow out of the engine bay.



Of course if you do have all the full sheet metal sealing the rad all around then I'm talking shyte.

inorder for this to happen on the 51 chevy truck 3100 series is near impossible in my eyes. the two inner fenders meet to the sides of the radiator. from top to bottom. top front edge to about half way down the hood latch covers. the only way hot air can go back to the front is when the hot air comes out the radiator to go down and back infront of the fan.....which i guess is possible????but with the fan blowing towards the engine i dont see how the hot air can move forwards.

my new infrared themometer should be here any day now. i had a good excuse to buy one this way i can see what temp the radiator really is and see if any cylinders are dead

[shtterbug8]

i would post pics of the fan setup but....GRILL is in the way. no good way to take a picture.

[squirrel]

The short water pump idea is a good one....I didn't think of that...

[shtterbug8]

Originally Posted by squirrel

The short water pump idea is a good one....I didn't think of that...

after being mentioned again....i looked this up. i would do this but...i think the water pump currently on the engine is the short water pump? the long neck ones on autozone look way different to me. anyone else agree?

[n847]

That is a long water pump! If you go to a short you are probably gonna have to get shims for your pulley, if you can even use the same pulley! You can always make a fan shroud to fit in just about any where, its been covered here many times! I'm not saying its easy but it could be done!

[hutchman]

Some interesting reading here on heat transfer in a radiator:

http://www.arrowheadradiator.com/14_...utomobiles.htm

....for those with an inquiring mind.

[shtterbug8]

finally got some numbers for you guys. the infrared themometer came in the mail today so the first thing i did in this freakin 105degree heat was go striaght outside to my none ac garage and fired up the chevy. the results are.....










inlet temp 199
outlet temp 165
core temp of rad...175
temp unit temp at water pump 210.
rad stat temp 199
when the thermo stat opened up i noticed the overflow puked a little water/steam. not hardly even noticable but i did see it.
this was with me in the truck every now and then reving the engine up to get the truck to warm up faster.

the temp guage read 225.

should i move the temp unit? seems like its reading accurate or pretty close.


things i still need to do....
buy a radiator cap that has a measured # on it preferred 15#
install a over flow catch bin.....ive got one just need to install.
possibly a shroud to block downward airflow going foward back thru radiator.
get a better ground on the sending unit. better grounds everywhere


also a buddy at work sold me a 12" fan i can possibly fit behind the radiator. the only thing is i wont be able to install in the center of the radiator due to the thickness of the fan but i will be able to make it a pull type. the fan has no markings nothing. he said he paid like $70 or so for it. just dont need it. sold his car before installed.

would 12" be good enough for my size radiator? can i leave the push fan on or should i remove?

thanks

[Home Brew]

Get a Lincoln Mark 8 fan and put a short water pump on it.. My 40 Willys ran hot in traffic with a 3000m cfm fan ( anyway thats what they advertised it as). I'm talking 220 - 240 hot but was fine on the highway. I took out the Ram Jet motor and put in a tunnel rammed 350 with a Big Muther Thumper Comp cam. While breaking in the cam I ran the motor at 2000 rpm in the garage with the Mark 8 fan, water only, and no thermostat and it never got over 185 and actually got down to 175 when the fan kicked on. These fans are cheap at the junk yard. I paid 15 dollars each for two of them. The only catch is they require a relay because they use a lot of amperage when running and a lot more when starting.

[shtterbug8]

yea im not running a relay on my fan and my fan is also running all the time. would not running a relay cause the fan to run slower?

[squirrel]

Can you relocate the temp gage sender to near the thermostat?

Interesting that the temp at the pump is so high.

[shtterbug8]

yeah...temp at the water pump makes no sense to me at all.the only thing i could think its because the temp unit is brass and it holds more heat????? the thermometer ive got is damn accurate also. really surprises me since i only paid $20 for it.

[groundpounder]

Originally Posted by ELpolacko

Never EVER have I solved an overheat problem by slowing anything down. NEVER!

The OP's issue is a small radiator and insufficient airflow at low speeds. 190-210 with a 16 psi radiator cap is normal. 50/50 mix of modern anti-freeze and water is all you need, the rest of it is snake-oil.

I guess people like Peterson, Moroso, Etc., Etc., have been using H2o restrictors for no reason........why doees the old traditional Chevy engine have a 1-3/4 lower hose and the top is 1-1/2?........just asking?????

Radiator Water Restrictor

Today's high flow water pumps work too well. They cycle the coolant through the motor well but when it comes to the radiator, often times it passes to quickly. This lower dwell time does not allow the radiator to cool the engine coolant properly. Peterson's new restrictor simply installs in the outlet hose and allows the coolant to slow in the radiotor, allowing proper cooling.


15-2001 Inline Water Restrictor

[kwoodyh]

Originally Posted by divco13

Put a 185 T stat. At idle the water is moving to fast to transfer the BTU's (heat ) to the Alum Rad. At speed the supply flow of cool ambient air is plentiful.
Needs restriction to slow down the water, in order to transfer the heat out of the water.
And course a well made shroud is the ticket.
My 502 run's a 185 stat, only very hot day's it get's to 200 degree's

Dat's the ticket!

[shtterbug8]

yall think i should dump that 160degree stat and get a new 185?....would the difference actually make it run cooler? it kinda makes since but then again....if i do this and run the infrared themo on it i will post the results for all to see.

[shtterbug8]

great news! i trial fit the 12" fan on the back side of radiator. i have enough room to run 2 of them suckers back there! very happy. im going to track down another to match it and run them as pullers and get rid of the pusher. im very happy now. this will definatly increase air flow. the big 17inch was blocking so much air flow being infront of the radiator.

[Cadzook]

The reason the fan could run slower without a relay is you may have a voltage drop because of small wires or switch. With a relay the switch does not carry the load and the power lead can come off someplace like the battery or a heavy lead like the alternator battery lead. Those fans pull a lot of amps so be sure to run heavy everything on the power feed, including the fuseholder.
I would run a 190 or so thermostat, because the engine is more efficient when warm. I think 160 is too cold.
On your catch can be sure that the hose connects to the bottom or shoves into the can to the bottom, so that it can return the coolant to the engine as it cools.

~Alden

[Lil32]

how about flushing out the radiator,my 32 coupe started running hot,mate suggested that as radiator had been in car a few years some. crap from the block could have found its way into rad.Fifteen minute air/water flush from bottom hose now has coupe running 160/175.my two cents worth.

[ottoman]

So at idle the coolants running too fast too transfer heat but at higher speeds, more RPM = faster flow, its not moving too fast to transfer heat?
I always speed up the pump on (oval dirt track) race cars when they had overheating issues, worked every time and have always went that way on street cars with similar success.

[unkledaddy]

Originally Posted by squirrel

Can you relocate the temp gage sender to near the thermostat?

Interesting that the temp at the pump is so high.

Originally Posted by shtterbug8

yeah...temp at the water pump makes no sense to me at all.

Cavitation or steam pocket?

[mschiffel]

220 degrees is nothing to worry about with a proper 50/50 coolant mix and a 14 to 16 # pressure cap.

[n847]

Originally Posted by unkledaddy

Cavitation or steam pocket?

^^^^^^I agree I'd find a way to try and bleed some air out of there, just incase!

[Cadzook]

A closed system will get rid of any air in the system. That is one of the functions of a closed system that make it desireable.
I just looked at a 1913 Cadillac at the Greenwood show in Seattle yesterday and it was born with a fan shroud. The engineers new back then the benefits of a shroud! After almost 100years you'd think hot rodders would catch on.

~Alden

[unkledaddy]

Originally Posted by Cadzook

A closed system will get rid of any air in the system.

How so?

[Gator]

When the car is hot the coolant expands, and you can puke coolant out of the radiator in even a properly set-up system. Even if the engine is not 'overheating' it continues to get hotter after you shut it off, because the coolant's not circulating BUT the heat is still there.

If you have a correctly built overflow set-up, the coolant is caught in the reservoir. When the engine cools back down it creates a vacuum in the system and will draw coolant back into the radiator. If it had just spilled out on the ground the radiator would now have a lower water level, which could cause it to run hotter...

It's cheap insurance, you can use anything from an empty beer bottle to a Moon tank. Most parts stores have a universal kit for less than $10. And since the 'overflow' isn't pressurized you can check the coolant level anytime.

[unkledaddy]

I think a prerequisite is that the radiator be higher than the engine block. In newer cars due to aerodynamic styling the engine is higher than the radiator and the cooling systems even though closed require purging.

[Cadzook]

Thanks for answering that, Gator.
The closed system really acts like a vacuum bleeder during each cool down cycle!

Unkledaddy, on my '49 Cadillac I placed the radiator lower than the top of the block. I placed a filler in the upper radiator hose, and drilled and tapped the water passage next to the thermostat housing and put a petcock there to bleed out the air. Without a closed system this type of setup would be impossible, as air would always be being introduced into it. (Edited to add; A surge tank mounted high will work, too.)

With a conventional setup(radiator higher than engine, I mean) the closed system insures that the radiator is always full, and without any air anywhere in the system a lot of problems are prevented. I would run a closed system no matter how ancient the rest of the setup! If the radiator is weak I would get the lowest psi-rated closed system cap I could find.

~Alden

[shtterbug8]

in the process of making a shroud. aluminum diamond plate. free. just time invested. should look good. i will post pictures once done. also installed the 12inch fan on rear of the radiator. will soon have two on the rear as soon as i can afford the second fan. running the big 17inch infront and two 12 in the rear im covering more radiator. should cool better than running 12 only in rear. liek i said i will post pictures of the rear fan setup as soon as i get the second fan. thanks everyone for the input.

[shtterbug8]

here is the radiator shroud i made. i still need to mount it but its so freakin hot outside i can barely mustard up the energy to take this picture.lol.

[Cadzook]

It is hard to tell from your photo, but it looks like it is just a shield. I was going to look for a photo of a well designed shroud, but then spied one in Deto's thread. Here is the link;http://www.jalopyjournal.com/forum/s...d.php?t=713213

He is using an electric fan, but has a complete shroud. The purpose of the shroud is to make sure any air pulled by the fan has to pass through the radiator. The better it fits the more efficient it is.

Alden

[shtterbug8]

i guess the purpose of mine is to keep the air moving rearward. here soon i will be fabricating up a air scoop to go near the bottom front of the radiator to help direct air to it and help keep air coming from the rear to front from below causing hot air to recirculate thru the radiator.

i cant make the shield go any farther back because then it will be covering up the pullies and engine lol

[gwarren007]

What year waterpump did you specify when you bought one/put one on?

[shtterbug8]

Originally Posted by gwarren007

What year waterpump did you specify when you bought one/put one on?

the waterpump is the one that came with the engine. i can tell its not stock and been replaced. painted different color. so at some point in the engines life its been changed.

[gwarren007]

you running a serpetine setup with a tensioner?



I will post this if you do have a serpetine setup with a tensioner. I think you have the wrong waterpump on your engine. I think you need a reverse rotation pump compatible with the serpetine setup - any 88-95 waterpump for a tbi engine will work.

[Cadzook]

Originally Posted by shtterbug8

Originally Posted by gwarren007

you running a serpetine setup with a tensioner?

The photos from earlier in the thread are self explanantory.
Alden

The comment you added has also been addressed in the thread.

[shtterbug8]

replacing the waterpump today since its kinda nice outside for once. wish me luck

[shtterbug8]

WELL....i got my answer. it was partically due to the waterpump. it was bad. but another cause didnt happened tell later in the day test driving it. apparently the timing gear has been shearing teeth off and picking up in the oil pump....while driving all of a sudden i lost all oil pressure and the engine blew. slung rod bearings out of the engine. completely disgusted right now. it does explain why it was overheating....because it kept going in and out of timing....why it constantly had to adjust timing because for some reason it ran ok one day and the next day ran like shit. .....basically my engine was junk for the begining and that was why it overheat.

[n847]

Bummer Man!