Coolant boiling on track

[94shodriver]

Last track day my coolant boiled over during the last session. Weather was upper 90s. Radiator and fluid are new this winter. Radiator is stock with the 3.2 fan set up. Radiator was replace because the previous one began leaking during track use, it was about 3 years old. Cap is about 3 years old, coolant boiled over in the overflow tank. Engine has 45k on sense a rebuild, including a new water pump. Hoses are at least that new. Everything I have heard is that the stock system is more that up to the task. My AC condenser is the original with 220k of dents in the lower half of it, I don't know if that's an issue. I would like to go to an all aluminum radiator, but they are out of stock right now. Anything I'm missing?

 

[RonPorter]

Worth changing the cap, they're cheap enough.

Did you burp it to get all the air out after the radiator change? Kind of a PITA to get all the air out.

Plus, the thermostat may have gotten sticky and didn't stay fully open. Could be worth changing that, too.

 

[jayro]

Are you running any coolant additives, such as Water Wetter? They probably are not required, but can help drop temps. I usually run mostly distilled water and a bottle of Water Wetter.

Past that I would follow Ron's advice. Replace the cap and the thermostat. It is cheap to do. I would also try and straighten the fins on the condenser and clean it out as much as possible to make sure you are getting maximum airflow through it.

 

[SHOdded]

Cleaning out the condensor is a great idea! It may not improve A/C performance if working well already, but will make the A/C system more efficient, and thus less load on your engine.

 

[94shodriver]

Themostast is about as new as the engine, maybe a little newer. Cap may be an issue, but I forgot to mention that the temp gauge actually got high enough for the check engine light to come on. Never happened before and I don't know if it was boiling over before ore after, I.e. which caused which.

 

[Off Road SHO]

Air flow or water flow problem. Sounds like air flow to me. The stock radiator and fan is more than capable of cooling it down, even on the track, if when the thermostat opens up for more water flow, there is enough air flow to cool the extra hot water. Remember the thermostat is mostly closed most of the time trying to keep the radiator from over cooling the water. The radiator, shroud and fan assembly is that efficient.

Tom

 

[94shodriver]

Tom, you think it is the AC condenser blocking airflow? The fans are functioning normally.

 

[Off Road SHO]

Undoubtedly. Remove the radiator, fan and shroud and power wash it from behind.

Tom

 

[Irish Pride]

Get a condensor comb at your local parts store to straighten the fins out.

 

[itwonder]

I would rent a pressure tester and make sure you don't have any tiny pressure leaks. The PCM turns to fan off above 40 mph, so it may tell you something if the overheating occurs on the track course or off.

 

[TimboSHO]

I put a police grille on mine and to keep the temps a little lower on the track

But I guess that doesn't help on a Gen 2... bummer

 

[RonPorter]

Supposedly the Police/Taxi grill on the Gen 1 was only good for extra cooling while idling in traffic. At any speed, the airflow does the job.

 

[luigisho]

. At any speed, the airflow does the job.

I don't know the ins & outs of how much improvement the police grill affords on a GenI, but I had a non functioning cooling fan on my '94 and drove it from basically the NC/VA border to just north of Hershey PA at highway speeds & didn't pop the rad. Only got sketchy with slow traffic on the DC beltway.

 

[TimboSHO]

Supposedly the Police/Taxi grill on the Gen 1 was only good for extra cooling while idling in traffic. At any speed, the airflow does the job.

I don't know the ins & outs of how much improvement the police grill affords on a GenI, but I had a non functioning cooling fan on my '94 and drove it from basically the NC/VA border to just north of Hershey PA at highway speeds & didn't pop the rad. Only got sketchy with slow traffic on the DC beltway.

I agree that when you keep moving it keeps the temps down, but the only thing I've done between my last autocross and the one I did on Saturday was use the police grill, and the coolant didn't come out of the overflow like it did in the past. The temp gauge was in a similar spot, but no more overflowing. It was also much hotter this time out as well. Not entirely scientific, but I think I'll keep using the police grill under hard use.

 

[RonPorter]

The fans cut off above a certain speed, as they become an impediment to airflow at higher speeds. The Police grill may very well help at the low autocross speeds. On the highway or a track, not so much.

 

[AREA 91]

Since you have a Gen II, check to make sure the black plastic lip is attached below the bumper on the rad support. This will make a difference in directing air flow to the radiator from under the car.