Over Heating

[b.reed]

Hey everyone, I have an 09 PFM (rotary) and always seem to have an over heating problem. If it's just sitting and idling or even on hotter days like at Indy this year during the SVRA event. I do not have a fan on the radiator but wanted to get some input on if maybe I should, would it stop the problem of over heating? Thanks in advance Brandon.

[jphoenix13]

I had a similar issue on my FM, after much troubleshooting, discovered the vent lines from the top of the radiators were plugged up with crap where they tee’d into the return header. That caused an air bubble in the radiators that restricted flow. Cleaned out the lines and fitting and immediately ran normal temps.

[E1pix]

I know nothing about this car, but the cheapest investment you can make is an infrared gun and some creative thought in taking temperatures.

[Purple Frog]

How long are you sitting and idling? They aren't meant to idle long.
There could be air in the system. Do you have bleeders on the tops of the radiators?
Are the fins on the fronts of the radiators all messed up from flying stuff? Could be you need to "comb" them back in shape.

[b.reed]

How long are you sitting and idling? They aren't meant to idle long.
There could be air in the system. Do you have bleeders on the tops of the radiators?
Are the fins on the fronts of the radiators all messed up from flying stuff? Could be you need to "comb" them back in shape.

The idling doesn’t take much time for it to start to over heat. There is not a thermostat in it. I haven’t seen bleeders on top of the radiator and the fins are not in the best shape. I’ll drain the water and pull the hoses and get the fins in shape. All that makes sense and thank everyone for their help!

[b.reed]

I had a similar issue on my FM, after much troubleshooting, discovered the vent lines from the top of the radiators were plugged up with crap where they tee’d into the return header. That caused an air bubble in the radiators that restricted flow. Cleaned out the lines and fitting and immediately ran normal temps.

I’m going to drain and clean the lines and double check all firings. Thanks again.

[CSasfai]

Brandon,
I have both an FM and a PFM. I always had to watch the coolant temperature in the FM while on the false grid or if there was an incident and we were held in the pit. My PFM has the electric fan and I have to say, it’s great to be able to sit idling and have the coolant temperature never go higher than about 190 degrees.

[jtaphorn]

My personal experience with overheating has generally led to the discovery of clogged tubes in the radiators. Much as I was wish it was something easier, it has not been. Brass rads are relatively easy to have opened and cleaned, aluminum another matter. Be careful with RTV around the engine and coolant area.

[Sidebite]

The idling doesn’t take much time for it to start to over heat. There is not a thermostat in it. I haven’t seen bleeders on top of the radiator and the fins are not in the best shape. I’ll drain the water and pull the hoses and get the fins in shape. All that makes sense and thank everyone for their help!

I have worked on several PFM you have to run a thermostat or a restrictor otherwise the coolant flows through the radiator to quickly and doesn't allow for cooling. Also the radiator caps need to be checked often so they don't open before 220F.

[jtaphorn]

The idea that coolant flows trough the radiator to quickly and compromising cooling is generally a falsehood. The science is more flow is your friend. I'll step out even further by saying single pass radiators cool better than double or triple pass because of the restriction in flow caused by the later. Also restrictors to slow flow are counterproductive to superior cooling.

Why? Because water/coolant absorbs heat best from the block when the difference in the temperature of the two is greatest. The longer the coolant dwells in the block and warmer the coolant becomes, the less effective it is at absorbing additional heat energy. Thus, replacing the coolant in the block with cooler water from the radiator is better. More flow wins.

Radiators are more effective dissipating thermal energy when the difference between the temperature of the coolant and ambient air is greatest. The longer the coolant dwells in the radiator and cools, the less effective the radiator is at removing additional heat energy from those coolant molecules. Flowing coolant, with a greater temperature difference than ambient, into the radiator quicker is more effective than restraining it in the radiator longer. More flow wins.

If you really want to dive in, I put this together a while back.

http://www.spacecitypanteras.com/Tec...g-JTaphorn.pdf

[Steve Stone]

Had overheating issues in my drift car after swapping it to LS1. Running 230 during long waits on grid. Added 1 gallon of VP Stay Frosty (100% water based coolant additive) Now stays at 187. Worth a look