Technical Any thoughts on overheating problem

Almost all of the bugs worked out on my 34 Dodge, changed to a 180 degree thermostat but car still gets to 240 on the gauge on the highway. Seems to be ok in town. Have a brand new aluminum radiator with an electric fan going the right direction. Any thoughts are appreciated.
Joe

 

We'll need a lot more details, and pictures would be a big help...several pictures, of the front of the car from a few different angles, including inside the engine compartment.

 

What does your gauge read when you put the probe in a pan of boiling water? In other words, is your gauge accurate?

Charlie Stephens

 

Air-in, hot air-out.
Pics of shroud(s)?
Fan location?
Exhaust type & routing?

 

Shouldn't even need a fan at highway speeds.. Low on coolant, poor air flow through the radiator, air going around radiator???

 

Remember the cooling "Rule Of Thumb". Runs hot at highway speed - not enough radiator. Runs hot at low speed - not enough fan. Looks like you don't have enough radiator.

Gary

 

Some Another things to look for is the water pump. It may not have the water flow capacity to keep your engine cool or the impeller itself is slipping on the shaft and not moving the water it needs to move. If your using aftermarket pulleys its possible that the water pump and/or the crank pulley is the wrong size which can slow down the speed at which the water pump is spinning and pushing water. Another thing to look for is the lower radiator hose. The lower hose should have a spring inside of it. This is because the bottom hose is the suction side where the water pump sucks water out of the radiator and pushes it through the engine. When the spring is removed or it simply rusts and disintegrates, this leaves nothing to prevent the hose from collapsing under the suction of the pump. If the hose sucks closed, it cuts-off the water supply to the engine. Sometimes the spring inside gets sucked-up inside the water pump inlet a few inches, which exposes a few inches of lower hose to be vulnerable to being sucked closed, especially after the engine has warmed-up and the hoses become even more soft and supple.

 

fan in front of radiator? just running electric fan? if metal fan, is it in the middle of radiator? automatic trans cooler in front of rad? have A/C? what kind of motor?

 

Iginion advance working properly??

 

Interested to follow this as I had a heat soak issue and solved it by adding a by pass with an electric water pump.

 

question ! if using a high flow waterpump and a performance radiator is it possible that at higher rpm the coolant isn't in the radiator long enough to cool properly

 

I was wondering the same thing. I believe the difference in temp. would be negligible. Even though coolant would be in the radiator for a shorter time during a cycle, it would cycle more times under operation and should at least even out or as I see it, provide more cooling.

 

Ask the guy about damage from operating engines with overly extended time to reach operating temperature.
Ask the guy about the combustion process when cylinder temps aren't where they need to be.


Removing the thermostat has always been a bad idea, it will take longer to warm up, longer to reach full operating temp, but then its double quick to over heat. Maybe buying that time masks a problem long enough to get to grandmas house, and that's all you really need but the trade off is driving an engine that never lives up to its performance potential and dies a quick death.

The idea is to maintain cylinder temps at optimal range. The thermostat does this by allowing the cooling process to begin. It establishes a "do not exceed" set point while allowing faster warm up to that optimal set point. It's really neat. Everything works flawlessly unless the generation of heat surpasses the ability to shed heat. The radiator must be able to shed heat faster than the engine can make it or eventually a over heat condition will result.

 

Forget the BS about water not being in the radiator long enough to cool it. That theory is contrary to every law of physics yet it continues to be inserted on every thread related to engines running hot. Its pure and simple Bull Shit. If that statement was even close to being true, why would anyone manufacture and sell a high flow water pump much less anyone buy one.

 

You do know that temperature change equations require a time factor right. There's no way to do one without knowing how long of a period of time the heat has to migrate to the cold. The greater the temp difference the faster it goes.



Place 2 objects one hot and another cold together for 0.00000001 second and note the temp change. Do it again for 10 seconds and again for 30 second.

Of course this is bullshit too and contrary to physics.

Heat leaves, cold never enters.

 

I had a similar problem with a '57 T-bird. Ran hot on the highway but ok at "in town" speeds. I tried everything I could think of, thermostat, radiator work, timing. Finally turned out to be a busted diaphragm in the distributer. I found it because I noticed a pulsing of the power at "in town" driving speed. Not very common but keep it in mind.

Charlie Stephens

 

The first thing I would do is make sure that the 240 degrees is accurate, using a tested
mechanical gauge or a non-contact themometer.

You should be able to smell "HOT" at 240 degrees at shutdown.........then try and
restart it. At 240 it shouldn't start easily if at all.

I tried two hi-flow water pumps and both behaved exactly like you (the OP) described. Once I replaced them with a OEM pump the temperature has been perfect.

 

yes, removing theromstats is a bad idea, I ran my Y block the first winter without a T-stat and it would warm up slowly and run abouy 150*. The problem is, that I would get alot of condensation in the breather cap and dipstick. I even had to wipe out water drops from inside the valve covers. I put in a 180* T-stat and no more condensation problem. also the car does not overheat.

 

all great info here but we need more info , any engine, tranny specifics, makes a big difference in helping, timing , carb tuning , engine speeds at highway speeds all make a difference. need more info

 

31Vicky makes a very good point. But flatheads heat up very fast without a thermostat. If they were run during cold winter conditions. I'd agree with him totally. From my experience running flatheads I've had great results with high volume pumps, no thermostat, a 4 lb cap, and a pressurized system. Of course a clean block, correct advance and proper fuel flow is first in the list. Yes, verify your gauge reading with a temp gun.

 

great point unkledaddy !we really don't know if there is an overheating problem it could be a wiring or gauge problem

 

Just my 2 cents, but I would check the temp gauge for accuracy as mentioned AND the sending unit. Does it (sending unit) have any sealant or Teflon tape on it? Where is the sending unit located?

 

I am sure he has already checked it as I mentioned it in post #3. Funny we didn't get a report on the results, I assume he read it. It is sure nice to get a report so we can scratch the item off of the list.

Charlie Stephens

 

Post pics and specs-be VERY detailed. Including the history of the engine and heads- I had a 360 mopar that overheated only on the highway- head had a crack by the exhaust seat. So IF IF IF the specs of your cooling system check out, it could be something along those lines.-rick

 

I want more BS physics lessons.
Or pointers at how to cheat at physics and win

 

Is it puking coolant at 240 it should be unless you have a very high pressure cap?

 

31Vick,
You just got too many dynes per erg!
Or was it kilowatts per ft-lb?

 

Yes

 

I don't know much about your car but when I have one that runs cool around town and gets hot on the highway I usually drill a few small holes ( like 1/8 or 3/32) around the perimeter of the T stat and that usually cures it.

 

I've seen similar year cars run hot because of no apron under radiator to direct incoming air through the radiator. Air just blows through gap underneath and not through as designed.