I installed an electric fan and now it runs hotter!?!?

Okay, so I've been fighting with this running hot issue for a little while now...'49 Mercury with a '61 390 Cadillac engine, adapter plate, turbo 350 automatic...it's a bone stock 390, rebuilt some time ago but before I owned it so who knows when. The engine runs strong...it's a Edelbrock 600 cfm 4 barrel carb, GM one wire alternator, and a becool radiator. The car would heat up sitting in traffic...180 when moving but would quickly climb to 200-210 sitting at stop lights...and it starts to run real bad at 210. I had a 4 blade mechanical fan on it, and the fan was pretty far away from the radiator, so I installed a shroud...I cruised it around that way for a couple days, and it seemed to stay right around 190...I decided to go one step better with it and switched to an electric fan over the weekend...now it sits and idles for a half hour and doesn't climb above 190-195...but the yesterday it climbed to 205 in traffic, and I've noticed that the electric fan doesn't turn off once it comes on. I just ran it for a half hour with the radiator cap off to make sure there was no air left in the system and it stayed at 190 the entire time, but again the fan never shut off. It's a stainless steel super stat thermostat that I installed about a year ago. I'm in Austin, Texas and the temp here yesterday was 95 when she ran 205 degrees, but shouldn't the electric fan make it run cooler? What am I missing? Thanks in advance for all of the help out there you guys and gals

 

What brand fan and how big is it? Is is a puller that goes behind the radiator ? Are you using a relay in the wiring ? How much of the finned area of the radiator does the fan cover ?

Don

 

That's not out of line with an ambient temperature of 95. As long as it doesn't keep rising and stays in the 200-210 area that's nothing to worry about. You mentioned something about it runs crappy. Not sure what you mean. Your fan temp sensor determines when the fan turns on and off. I can tell you right now it's not going to turn off in 95 degree heat. Rule of thumb,when one runs hotter in traffic and cools down when moving that's an air issue. When it does just the opposite it's a water flow issue. You can hunt and hunt and spend a lot of money and still make little or now progress. If you have ever noticed front bumpers on 88-98 Chevy trucks, the difference between a 1500 and 3500 front bumper. The 1500 has an air deflector on the bottom and the 3500 does not. The reason is the 1500 is lower to the ground and needs the deflector to break the vacumn of hot air coming out of the radiator and being drawn back in through the front again. You may consider if you have room,finding some sort of deflector off a donor car and attaching it to the core support and see if this helps.

 

The fan was given to me by my boss...I was assured it's a good one, although I don't know the brand...it's a 9 blade puller...I've got it between the radiator and the engine with a relay that's controlled by a temp sensor that's pushed into the radiator...the relay, wiring, and temp sensor are all Hayden and they're new...I bought them on Sunday. What I mean by runs crappy is it starts to detonate at 210...as far as finned area of the radiator that's covered, I'd say approximately 75 percent...it's a significantly bigger fan than the 4 blade mechanical one I removed...

 

180 when moving but 200-210 in traffic. Definitely an air flow issue.

Are you sure the fan is a puller? Working as it should? Don might be onto something as far as the area covered. The mechanical fan with the shroud essentially covers the entire area of the radiator...but the electric one doesn't.

The detonating leads me to think you should check that the timing isn't advanced too far, or the fuel mixture isn't too lean.

 

Personally, I'd get rid of the electric fan--I'm not a fan of electrical parts that can fail and leave me stranded.

What kind of fan shroud did you have on it? Factory for the car, something OE that was for another application, or a universal?
One that might fit, if you can't find an original for your car, might be a '54 Buick.

Either way, ditch the POS 4-blade fan, and go through the YearOne catalogs and get the largest diameter 7-blade clutch fan you can find that fits your shroud opening.

Instead of a 180-degree t-stat, switch to a 160 for the summer. My theory on them is that they open sooner and get the water flowing through the radiator and cooling quicker, maintaining a lower temperature. It buys you time in traffic, because it starts climbing from 160, rather than 180.

Get a radiator over-flow bottle, to recover your lost water when it does start getting hot and pushes past the radiator cap to the overflow tube.

You might consider bumping up the pressure for your cap, though that's a stop-gap measure.

Finally, Water Wetter really works. There are very real technical reasons that I've explained in magazine articles in the past, but don't feel going through all of that here. Just trust me--its not snake-oil, and not only is the science behind it good, but I've used it myself in a '54 Buick in Florida.

For my daily-driver '61 Suburban, I have a 4-row radiator, no shroud (never got around to installing it!), 160-degree thermostat, 7-pound radiator cap, water/antifreeze mix with no Water Wetter, and a 7-blade clutch fan from a Big Block A/C Mopar application.
The fan sits about 8 inches from the radiator, which is a ridiculous amount. The factory shroud would accommodate that and make it inconsequential. 350 small block, manual trans.

At idle, that fan pulls enough air through the radiator to hold a piece of paper tight to the front of the radiator core, even sitting 8 inches back from the radiator. It MOVES some air!
Also, I looked at a Flexalite metal fan, same number of blades, same diameter, and the Flexalite had a warning sticker that said do not use above 4,500rpm. No such warning on the fan designed for big block Mopar muscle cars.

The mounting holes for the fan and clutch are the same for Chevy and Mopar... Should be the same for all GM, including your cad.

I drive in Atlanta stop-and-go traffic in the summer, with little worry.
I need to get the fan shroud on, and install an overflow bottle. I am certain with a shroud, I could idle forever and not overheat.

-Brad

 

Like Rickybop stated,look at the distributor. I'm not familiar with the distributor on those early Cady motors. If it has a vacumn advance make sure it's not sticking.

 

Are you sure its pulling and not pushing. As strange as that sounds one of my club buddies did that.

 

Id find a new club

 

Wow! Thanks for all of the information guys...I really do appreciate it! The fan blows Alot of air at the engine...and I mean alot, but it doesn't seem to be pulling that much through the radiator...does this mean it's running backwards?

 

I realize it's trying to pull air through all of those tubes...and if i blow cigarette smoke into the radiator front it pulls it through, but it certainly doesn't seem like it could hold a piece of paper there if it had to...but then in the space between the fan and the engine block it's like a hurricane...

 

run the fan and hold a rag in front of the radiator , it should suck the rag onto the radiator , it it dosn't reverse the two wires at the fan and try again .


.

 

Is it sealed all around? In other words is it pulling that air from the sides of the shroud instead of through the radiator? By chance, do you have a picture?

 

It's not sealed all around...and unfortunately a pic prolly wouldn't turn out right now...the car's in the driveway in the dark...I'm without a garage for the time being...

 

So I've got a pic now...it actually came out with the camera phone, but I'm posting this all from my phone as I'm without a computer right now...and it won't let me upload from the phone unfortunately...

 

If by sealed all around you mean that the radiator is tight between the inner fender wells, then yes, it is sealed all around...it wouldn't be possible for the fan to pull air around the radiator on this...

 

A good electic fan should have a noticeable air draw thru it, lots of halfass fans on the market, get a good one.

 

I really do appreciate all of the info fellas...I'll have to get up early and try the rag trick before work...

 

I hate to bust your balls CadillacKid, but your overheating is not your biggest issue. Not by a long shot.

I noticed you said that you could blow smoke at the radiator and the fan would pull the smoke through. Your biggest issue is that you obviously SMOKE. PLEASE STOP and STOP NOW. Take it from me...seven by-passes, one stent and more coming. All due to smoking.

OK, since I'm not your dad, I'll get off your ass. I just had to speak up.

Good luck on the overheating.

 

Thanks Beep...yes, I know it needs to stop...I've been using an electronic cigarette for the most part these past couple of days, so your warnings just solidify my quitting process Thank you again...

 

My friend built a chopped '49 Merc. It had a chevy 350/350 with A/C. He had installed an aluminum radiator with dual electric fans. He spent a few years trying to get the car to run cool. Finally, he had the hood louvered and that cured his overheating.

 

The only electric fan I'd buy is a Spal. They will flat out blow your hat off. They don't use them on Ferrari's for nothing. All other electric fan CFM ratings are BS. I have never had an overheating problem using a Spal puller.

 

I believe you running bad at high temp issue may be due to Ethanol in the fuel. Alcohol boils at 178 degrees, not a problem for FI cars however, carbureted cars that store fuel in the float bowls lean out when the fuel temp exceeds 178. I am fighting the same issue currently as my county mandates e85.


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No...he meant sealed around the shroud where it contacts the radiator. And there's your problem...at least a big part of it. Fan is pulling air from around the edges of the shroud instead of through the radiator, and that's why it seems like a "hurricane"...it's mostly just circulating the air in a circle. You may get by with putting some sponge rubber between the shroud and the radiator, but I'd toss the electric fan and go back to the mechanical fan and full shroud. Or get an electric fan with a full shroud that seals all the way around the radiator...so air is pulled through all the fins. Still check your timing, advance, and fuel mixture. Let us know how it turns out.

 

Take a word of advice from someone who has survived throat cancer: Dump the cigs. I was over two packs a day and quit cold turkey. If I can do it so can you. You do not want to experience the chemo and radiation treatments. I would not wish that on my worst enemy.

 

I was reading the posts. I didn't see these questions or answers, so I want to ask.

How many cores is the radiator?

The electric fan restricts airflow until it turns on, then only utilizes the portion of the radiator it covers...

Your shroud, how far in was your 4 blade fan? it should be 2/3rds in, and when the fan is spinning, the air should be blowing out at roughly 45 degrees.

Ditch the 4 blade fan, SPeedway has a nice 7 blade fan for aggressive cooling and air flow.

IF your water pump pulley, and your crank shaft pulley are the same, then your runnin 1 to 1, you can spin it faster by going larger on the crank, and smaller on the pump..... This is whats run on todays engines...

 

If the car ran cooler when you put a shroud on it with a fan blade, why don't you put that back on and be done with it?

 

Had similar issues with the 54... make sure you are running a high amp alternator that can keep up the RPMs on the electric fan. I was trying to run a dual fan with a stock alternator and one relay. When I replaced the alternator with a 100 amp powermaster and burned up the fan relay, I realized how much juice they were drawing. Now I have dual relays with big thick wires going to fans and I have noticed a vast improvement in traffic. I also have a Flowcooler WP, and bought some additive similar to Water Wetter out at Austin Performance(don't recall the brand offhand, but they will help you)... I also have a Vintage A/C setup running in the car.

 

I'm gonna sound like the complete troll in this deal, but why would you guys consider an electric fan an improvement over a mechanical? That absolutely blows my mind! A good mechanical clutch fan and shroud will almost (like 98%) always out flow an electric fan. I got obsessed with them about ten years ago because I wanted that "last 10 H.P." that I was losing with the mechanicals that I had been running. The very first thing I found out was that on my daily driver hot rod, it didn't matter what I spent, I couldn't by an aftermarket electric that would last an entire Phoenix summer. Period. After going through two or three of different price levels, (and yes, correctly set up with relays and temp activated switches) I started to really look at electrics. My buddy ElPolacko had 6 or 7 of them that he had taken off of customer cars over the years, and we did some non scientific testing with my car... Long story short, a simple five bladed cheapo flex fan without a shroud flowed more than the most expensive electric!
My car has happily used a 7 blade Cadillac clutch fan and shroud for about eight years now and will sit in heavy Phoenix traffic on a 118 degree day with the A/C without going over 200....

 

hopefully you know someone on here that has a computer that you can use to post some pics. again, how many rows in radiator? is it a direct replacement for a stock one? what is the pressure ratings of radiator cap? running coolant/water mix? what is the temp rating of thermostat? some times air can move over/under radiator unless there is a good seal with it and hood, etc. unless you have a switch with a manual over ride fan will stay on once high temp is reached. fan shut off when you turn ignition off?