Another hot idle thread

[Inacommando]

‘71 GTX 440 4v .484 cam. Overheats at idle after driving for a few miles. Revving helps so it indicates air flow issue? Added aluminum 22” 3-core rad with 16”pusher fan. No change. Running straight fan with spacer. Ordered severe duty fan clutch. (Not here yet ) Here is a pic of the current set up. I would like to add the smaller A/C pulley but wanted to confirm what to get. Any recommendations or points in the right direction would be appreciated

 

[toolmanmike]

‘71 GTX 440 4v .484 cam. Overheats at idle after driving for a few miles. Revving helps so it indicates air flow issue? Added aluminum 22” 3-core rad with 16”pusher fan. No change. Running straight fan with spacer. Ordered severe duty fan clutch. (Not here yet ) Here is a pic of the current set up. I would like to add the smaller A/C pulley but wanted to confirm what to get. Any recommendations or points in the right direction would be appreciated

View attachment 1679273

Have you done a cooling system test? Pressure test your system and the cap. That's good for a start. When you say "heating up" what temp is it getting up to? Is it puking coolant or just high on the gauge?

 

[ruffcut]

A shroud would help. And a better water pump as FlowKooler would help also. ruffcut

 

[Orig69]

‘71 GTX 440 4v .484 cam. Overheats at idle after driving for a few miles. Revving helps so it indicates air flow issue? Added aluminum 22” 3-core rad with 16”pusher fan. No change. Running straight fan with spacer. Ordered severe duty fan clutch. (Not here yet ) Here is a pic of the current set up. I would like to add the smaller A/C pulley but wanted to confirm what to get. Any recommendations or points in the right direction would be appreciated

View attachment 1679273

If it's overheating after driving for just a few miles it must have a lot of air in the cooling system, or something wrong with the thermostat.

 

[Inacommando]

I have tried it with no thermostat and I have re-filled it as a have with dozens of radiators over few past few decades. I will try putting it up on ramps with the cap off to see if I can “burp” it

 

[Inacommando]

Have you done a cooling system test? Pressure test your system and the cap. That's good for a start. When you say "heating up" what temp is it getting up to? Is it puking coolant or just high on the gauge?

Just high in the gauge but it is exhibiting other signs off being hot such as “dieseling” after shut-off when reading very hot. I am using the factory gauge and it is not gradated by numbers but it goes to the far right bar. I have tried two radiators and three caps. It has not puked coolant to the extent that it overflowed the overflow reservoir

 

[Orig69]

I have tried it with no thermostat and I have re-filled it as a have with dozens of radiators over few past few decades. I will try putting it up on ramps with the cap off to see if I can “burp” it

I would make sure to install a good thermostat next put it up on the (Rhino) ramps and slowly fill the cooling system with coolant, then (with the radiator cap off) block the wheels and run the engine to operating temperature and check for air bubbles.

 

[AR67GTX]

I would try adding a shroud, remove the pusher fans (obstructing the rad), and check the radiator cap or replace it. Also, without knowing your setup, you might see about getting some more timing at idle - either by limiting centrifugal advance so you can bump your initial advance higher, or switch your vacuum advance over to manifold vacuum to bring it in at idle.

 

[hunt2elk]

Go to Harbor Freight and buy a cheap infrared temp gun and shoot different areas of the cooling system. Then you will know exactly what you are dealing with. Agree with installing a shroud and radiator support to hood seal. Get rid of that electric fan. Also, if you carb is running lean, it will cause higher water temps.

 

[Inacommando]

A shroud would help. And a better water pump as FlowKooler would help also. ruffcut

Thanks. I have ordered a speedway universal shroud to see if I can make that work.


I have a 512” to go into it but due to circumstances beyond my control it will not go into the car until August

 

[Inacommando]

To follow up:

I completely drained the radiator and replaced the thermostat with a hi-flow 160 deg unit. I upped the primary and secondary jets in the vac secondary 750 cfm carb. I left the timing alone. I then refilled the radiator with the drained fluid as it was installed only two weeks ago and had been treated with Water Wetter. I turned on the heater to high, pulled the car onto ramps, and ran it with the cap off. I ran it until the t-stat opened and I was then able to top it off with 1 to 2 quarts of 50/50 mix (green.) The car never overheated. I buttoned her up and went driving. It ran slightly warmer when on the move from its previous position at the first line past the col setting but never went past 1/2 on the gauge even when stuck in multiple traffic cycles and when left to idle for 30 minutes on an 88 deg day. I am calling it cured and will decide on whether or not to swap the fixed fan for the thermal clutch fan set-up as I am happy with the current results. I am at the same crossroads with the shroud.

Thanks. I have ordered a speedway universal shroud to see if I can make that work.


I have a 512” to go into it but due to circumstances beyond my control it will not go into the car until August