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Running Hot

2K views 8 replies 9 participants last post by  farna 
#1 ·
The car was a trailer queen (39 Ford Std 350 SBC; pics attached) so cooling was not a concern. All it had was a 1250 cmf pusher in front of the condenser. I am converting it into a "driver" so we installed a 1750 cfm puller and added a shroud to better direct the air. We also changed the thermostat from a 190F to a 160F.

It still runs hot (190-210F) and overheats in stop & go situations (+230F).

Yesterday at our weekly breakfast one of the more seasoned gearheads said "maybe you've got the wrong waterpump; your serpentine set-up has to be a reverse rotation pump.

How can I check the rotation of the waterpump without removing it? Is there anything else I should check or try to get improve the cooling?

I have thought of a mechanical flex fan, but space is limited.(the radiator would have to be replaced with a norrower one and puller fan would have to be removed. I will try anything that will keep me from going to all that work and expense.
 

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#3 · (Edited)
1250 cfm is simply not enough airflow to cool yours unless you're living in a cool climate area where you won't need drastic airflow to keep it cool. I would guess the 350 is a mild horsepower rating around 300s. Personally, I would stay away from aftermarket electric fans since they tend to be overrated however in your case since space is a factor, I would check out zirgo fans.

The reason I would consider them an option (yes, "some" fans are a bit pricey) is that not only do they have cfm charts, their ratings are supposidly already rated at 1" of static pressure compared to almost all other fan ratings on the market that are rated at 0" of static pressure, meaning no flowing interference like a radiator behind it. Their cfm ratings are pretty high too. I don't believe that you can check your waterpump if it's veins are flowing the right way without removing it. I doubt that would be your problem but it's always a possibility.
 
#4 ·
Don't do anything till youve ruled out the thermostat,try running without one,just to see if it runs cooler.

I just finished rebuilding an engine and I had a new thermostat in it,it over heated the first day,blew off the bottom rad hose and lost 2 gals of antifreeze,so replaced it with another new one,same thing,another two gals of antifreeze gone.

Now I'm thinking the same thing,water pump?,head gasket?,fan belts/clutch?,just what the hell did I do wrong on this motor?

Thermostats are cheap,so tried one more,noe it runs fine,actually a little too cool with the 160.

Seems like about 3 or 4 out of every ten are bad nowadays.

Had a guy in my shop whose engine was overheating,he had another shop replace the thermostat with no change,so they replaced the water pump,no change,they replaced the fan/clutch assembly,nothing,finally replaced the radiator,still overheated,I pulled out the thermostat for him and it ran cold,replaced it with a good one and he was on his way.
Pretty expensive thermostat. :pain:
 
#6 ·
rednekskunk

check to make sure you have the right DIRECTIONAL fan as there are 2 types of fans one blows forward and the other reverse. also try waterwetter in the coolant. make sure radiator has enough cores to direct coolant away from heat. check thermistat. I dont think you have a reverse direction waterpump, my guess is something simpler. good luck
 
#7 ·
KONADOK said:
The car was a trailer queen (39 Ford Std 350 SBC; pics attached) so cooling was not a concern. All it had was a 1250 cmf pusher in front of the condenser. I am converting it into a "driver" so we installed a 1750 cfm puller and added a shroud to better direct the air. We also changed the thermostat from a 190F to a 160F.

It still runs hot (190-210F) and overheats in stop & go situations (+230F).
Some comments, questions and suggestions.

When you say it overheats (+230 degrees), is it boiling over or is that what your gauge is reading?

If your temperature sending unit is mounted in the head (rather than in the intake manifold) your temp reading will be about 20 degrees higher than actual coolant temp due to the sending unit being located close to the exhaust port. The radiator will not be boiling over even though the reading appears high. This is normal.

Use a good 180 degree thermostat.

Use a 16 lb. pressure radiator cap.

Check upper and lower radiator hoses to be sure they are not collapsing.

Be sure your ignition timing is correct. A retarded ignition can also cause overheating. Carb setting too lean (vacuum leak also) can also cause overheating. Look at your exhaust pipes just below the headers. Are they glowing red? Sure sign of retarded ignition or very lean carb settings.

A puller electric fan is more efficient than a pusher. Run it full time when the ignition switch is in the "ON" position. I have found that the aftermarket thermostatically controlled electric fan switches do not perform satisfactory.

Are you running a 50/50 mix of water and anti-freeze? Do not use the so called environmentally safe anti-freeze (Beige in color) as it has a tendency to "Gell" and will clog up the system.

Be sure to have as unrestricted a flow of air going into the radiator as possible.

Hope some of this helps.
 
#8 ·
Info on your serpentine setup--If the water pump pulley has a smooth surface, Its "normal rotation" setup---If it has the belt grooves, Its a reverse rotation outfit. You can check the casting number on the pump to see which type it is, but that's 50% at best because it may be a normal with a reverse kit in it from the rebuilders. The ONLY way to tell is to remove the impeller cover and look.
 
#9 ·
190-210 is actually a normal operating range for a fully warmed engine. 190 and 195 thermostats are now common. The t-stat regulates engine temp, so it should run a bit above the t-stat opening temp (opens at rating), at that temp at best. 230 shouldn't be "running hot" either, not with a good pressure cap. If you're not running a 13 or 16 psi cap, you need one. The more pressure, the higher the boiling temp of the coolant. You shouldn't be too concerned unless topping 230 degrees on a regular basis.
 
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