Technical '51 Runs hot @ idle

Hey, gang. I have a '51 Chevy Styleline Deluxe, w/ a 285hp 350. The radiator is 3-core aluminum with an electric fan. I recently installed a 180 stat in the cooling system. The water pump is new.

Driving, the temp is perfect. If it idles more than a few minutes, no matter the outside temp, the motor spikes to 245-250. It has never boiled over.

The problem I see is the hood covers the top 2/3rds of the radiator.

Any ideas on how to get rid of some heat at idle?

Thank you! - Arch

 

What is your ignition timing set to at idle?

Where is your vacuum advance connected?

 

Shroud?

 

if that was the issue they would all overheat.

 

Does the electric fan come on? If it does, I think you need a bigger fan since it only happens at idle.

 

Are you sure you don't have any air trapped in the radiator? HRP

 

It sounds like an air flow problem. Is your fan running, if so what temp does it cut in? Have you room to install a larger fan or a second fan?

You don't say if your fan is a pusher or a puller. If its a puller, a more effective fan shroud might help get more air through the radiator.

 

Lots of good replys--I have done many 40's with 327 etc and ac. All have had Cooling Components elec fan setups. Never a heating issue no matter how hot or in traffic. They come on with AC, from engine sensor at 180 or manual if needed-- no issues.

 

Correct water pump? CW or CCW...?

 

From personal experience I would say that it is an air flow problem. Simply because as soon as you get enough speed for enough air to go though the radiator it quickly cools down.
Is the fan large enough to cover as much of the radiator as possible ? do you have a shroud around the fan to direct air though the fan so it pulls air from the whole radiator? Does the fan have proper blade design and enough CFM to pull enough air? Note if you check the Spal listing on their fans (standard of the aftermarket fans) they have different cfm ratings for the same size fans. A cheap Ebay or parts house fan may not pull enough air.
It doesn't sound like the air flow is blocked as it does cool at speed.

My personal observation was that the wrong rotation pump would somewhat cool at an idle but the engine would over heat at speed. That was back in about 1992 when someone stuck a mid 60's 327 in an early 80's Camaro and then a shop installed a pump for the model of the Camaro rather than the model of the engine with V belt drive.

To the OP, you still have to have the correct pump for the BELT setup you have. V belt taking a clockwise rotation, Serpentine taking a counter clockwise rotation. Check the part number to make sure that your pump matches your belts. I don't think it is an issue but one thing to check mark off the list.

 

Air moves from a high-pressure area to a low-pressure area. At road speed, on the highway, this is simply a natural event due to the air stacking up in front of the radiator and the engine compartment being at a lower pressure. This is why your vehicle doesn't exhibit any overheating while driving but does when idling or in traffic jams. This is a major clue telling you where to look.
A fan is a mechanical aide to create a low-pressure effect behind the radiator for those times when you are not pushing down the road. But you need a properly designed shroud so the fan will only scoop and expel air that has passed through the radiator. The shroud is sort of like a dam that keeps engine compartment air from displacing the air that you do want to move.

 

Try a big steel bladed mechanical fan, summit has them, I use a 17" on my Deuce & Brenda's wagon,never any overheating problems. HRP

 

See post #2.
Retarded initial timing will cause low speed heating.
If that is ok then look at improper proper air flow.

 

Thank you all for the suggestions! I knew I could count on you. I have no shroud. Looks like I need a bigger and better electric fan or may go back to a 17" mechanical and build a shroud. I'll check the timing. I know there's no air in the system.

Thank you again!

 

I have used the fan HRP shows on a few cars with a shroud and worked well but too tight in a 40. A guy had a 40 with a 327, no ac and a walker radiator. Had a good mechanical fan as well. There were no issues until he went up his hill about 10 mph-it was maybe a 1/2 mile or more. By the time he got to the top it was pegged. Put a Cooling components elec fan on it--problem gone

 

I think if you build a shroud you will be all set , not only to cool the radiator but also direct airflow over the engine.

 

Annnnd the pump I put on was an extra my friend had. His is a newer 350 w/ a serpentine. Mine is 25 or so years old. Doh! Guess I need a a proper pump.

 

Check timing first then do a shroud. I would build the shroud anyway