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YOUR RESEARCHRace car over heating mystery
Leading reported evidence
Check blocks or crimping
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
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1
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Performed · outcome unconfirmed · Original poster
Water pump replaced, thermostat replaced, all hoses checked for blocks or crimping.
Leading evidence: 'Check blocks or crimping' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check blocks or crimping' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
Water pump replaced, thermostat replaced, all hoses checked for blocks or crimping.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Performed · outcome unconfirmed · Original poster
Water pump replaced, thermostat replaced, all hoses checked for blocks or crimping.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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19 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T135432Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
3.6 stock engine. Only overheats when pushed hard on the track. Water pump replaced, thermostat replaced, all hoses checked for blocks or crimping. No loss of power . Air flow fine to radiators. No leaks. No water in tail pipes, no water in oil, normal pressure in expansion tank. Totally miffed. Ran fine before the Glen race.
Any ideas where to go from here ?
Assuming you already have the 3rd radiator installed:
1) pull bumper and clean radiators fins really good, and also between radiator and AC heat exhanger. These get clogged easily
2) If legal, cut throught the finder liners behind the radiators so that the air flows directly back [like the are on the GT3]. Sometimes, the air flowing down the 90 degree ports slows the escaping heat-exchanged air, basically a restricted airflow. As a bonus, this hot air from the radiators (hot for engine purposes) can also be vented directly to the rotors (cool for brake purposes).
3) Driver slower.
-td
How do you know the engine is overheating? Is there a warning light on or some other positive way to know the engine coolant temp is too high?
Do you know the coolant temp by an accurate gage?
What are the symptoms of the overheating condition?
Be sure the radiator fans come on when the coolant temp reaches 212F and they should shut off when the coolant temp drops to 205F.
If the coolant temp continues to climb to IIRC 216F the fans should switch to high speed mode.
Sincerely,
Macster.
Crap thoroughly cleaned radiators spotless. Car has been running really well until last weekend. Before this situation the gauge pegged at 180-190 even when racing.
Coolant gauge says 250. From what I understand fans are worthless if you are getting good air flow which it looks like I am. Fans are only for stop and go traffic. In fact a lot of guys remove the fans in race cars. Cup cars don't have them.
We are going to test with a gauge besides the one on the dashboard to see if that is bad. Gauge shows the car is at normal operating temperature unless it is pushed on a racetrack. Driving it around town or idling for a while it runs around 180 or so. The fans do come on at idle too.
Is the system holding pressure? Reservoir, cap and purge valve all good?
"Pressure cap and reserve tank
As coolant gets hot, it expands. Since the cooling system is sealed, this expansion causes an increase in pressure in the cooling system, which is normal and part of the design. When coolant is under pressure, the temperature where the liquid begins to boil is considerably higher. This pressure, coupled with the higher boiling point of ethylene glycol, allows the coolant to safely reach temperatures in excess of 250 degrees.
The radiator pressure cap is a simple device that will maintain pressure in the cooling system up to a certain point. If the pressure builds up higher than the set pressure point, there is a spring loaded valve, calibrated to the correct Pounds per Square Inch (psi), to release the pressure."
http://www.familycar.com/classroom/coolingsystem.htm
Delete the A/C, remove fans, and the condenser which block flow to the radiators. Check your class rules, I have no idea what you are allowed to delete.
Good advise form multiple sources above. I'd immediately replace the coolant tank and cap if they're at all yellowed. Expensive, but crucial. I'd also run L & N's 160 degree T-stat if it's a track only car.
I blew my 3.4 with about 60 race hours on it in NASA's Nationals last Oct. at Miller in SLC. I overheated badly in the second of the 2 qualifying races as it was very hot, and blowing 30-40 mph down that long main straight right in your face. I have the center radiator, but all 3 of mine were pretty gummed up when we removed them. They didn't look that bad, but when dipped the amount of junk that dislodged was amazing. I threw away the center one, the others were fine. In that second race I watched the readout go to 240 as I was trying to backoff the throttle and still hold onto first place in the race. Bad idea, it blew in the next races after only a few laps. Don't make that same mistake, get it figured out.
Definitely remove the fans and the shrouding around them. Besides saving about 10 lbs. per side, your car will run 10 degrees cooler when you removed that crap. Mine ran at 190-200 this past weekend at Cal Speedway going 150 + with 80 degree exterior temps....
Put it on a dyno with some gauges attached and looks like a low fuel pressure problem when the engine is run hard. Car is running ultra lean causing the overheating. Putting in new fuel pump and doing a test and tune Friday. Never would have thought it could be a fuel pump issue. Hope this is truly it and resolves the problem.
Thanks for the follow up, noted in case I ever have a similar problem. I put a 3rd radiator in and cleared all the A/C equipment blocking airflow after overheating at a Dallas area club race last year in +100 degee weather. The event has been moved from Memorial day to late October this year.
possibly higher octane or lean mixture? A friend that worked at the airport told me a story of a broken down fuel truck the company wasn't going to fix so guys would once in a while mix that fuel with normal gas in their cars since trying it in their cars when the tanks were low was giving them hot engines. So if you do have an in for tax free aviation fuel maybe dilute it more. I don't thing non race fuels would make much difference. I think octane booster stuff gives heat. Also some tracks requiring no antifreeze getting guys to use water wetter or whatever might give heat.
Soooooooo what oil are you using
Could be the oil
Head gasket starting to go, or cracked cyl head or wall ???
Also, do you still have cats on the car ? Any chance they are clogged ? You can remove and check or monitor the temperatures and tell.
Our thoughts too until the fuel issue showed up on the dyno. Not Cats. If for some reason the fuel issue isn't it the Head gasket is next.
If it were a head gasket wouldn't there be some kind of symptom like water somewhere ? Tail pipe ? in the oil ? a leak of some kind ? water loss in the tank ?
Similar experience in my 6-cup drafting a 993 RSR. My cup overheated and I had to shut down. Figured out that RSR air-cooled motors put out very high exhaust temps which were my radiators only source of airflow. Cooled down and ran fine from then on....
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