Hi guys, sorry to post another question about a topic that is widely known for issues. Today was about 80 degrees and I was enjoying a track day with my r53. After my last session, peak heat of the day i turned the car off, the auxiliary fan stayed on after the car was off, when i revisited the car it was dripping coolant onto the ground, it was running down the engine block and dripping off the oil pan, drivers side of the motor but we could not find the source. One of the track personnel said the he had experience with bmws and minis that after being tracked they would "purge" their coolant when they were too hot / pressurized. Is this possible?
I let the car cool down, the coolant level went down to the min line when restarted, drove around including highway driving, no more leaking. Added coolant drove around more, still nothing. All shops were closed today and my event continues tomorrow so I don't want to miss a day but I dont want to leak coolant onto the track. Thermostat, housing, gasket all replaced a year ago, waterpump two years old, coolant expansion tank less than a month old.
Thanks for any input, I apologize for the long post.

 

The first thing you want to do is remove the airbox and intake hoses and get in there with a flashlight to see if you can find some white trails that would indicate a leak. You could also take it to a shop and have them pressurize your coolant system and observe for leaks. Really, all of the coolant-carrying items you mentioned (except exp tank) are on the driver's side so you'll need to get a close look to determine.

Thermostat gaskets are tricky on this car and if someone installed it using a sealant it can actually cause rather than prevent leakage.

Lastly, and this is just me being curious, what track allowed you on with any sort of coolant besides water? I always thought you couldn't use coolant because if you leaked on-track it made it extremely slippery and dangerous.

 

+1 on accessing a couple of things to take a better look and maybe find the trail

To answer you coolant question, most organizations that run HPDE or TIME TRIALS allow daily drivers with no modifications. As it's gentleman racing with no contact or dive bombing corners there is little to less chance to spill coolant. Of course part failur can happen but they have corner workers usually to black flag you if you start to drop parts or fluids.

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Thanks guys for the quick responses, I'm trying to find a shop this morning to pressure test it and I will remove the airbox and intake hoses to get a better view.
Like Drivehard said, its just an hpde, a lot of stock daily drivers are out there. Luckily it didn't leak on the track because like you mentioned that could make conditions extremely dangerous.

 

When I replaced my super charger I did not get the clamp on the hose real good under the super charger. Mine started "burping" coolant and I could not figure out why and didn't figure it out until i pulled the air box off and poked around.

 

Thank you all for the help. the clamp on the hose coming out of the thermostat wasn't tightened down all the way, wasn't leaking when running but during cool down after about 30 minutes I guess it was building heat and pressure since no circulation was happening. After tightening the clamp I ran two more sessions, after each session I'd leave the track and go down the nearby country road to help it cool down. Didn't have any more issues and was able to enjoy the beautiful new NCM motorsports park.

 

Great news. Another problem solved!

So how did you do at the track. Were you timed ?

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It went extremely well, most fun I have ever had at a track event. Technically we weren't allowed to use timers, however we were allowed to record our laps, so afterwards I found my best lap to be 2:44.8 for the 3.2 mile grand full course layout. This comes with a disclaimer that I am obviously not a pro at this, I run in the intermediate groups, only mods are 15% pulley, intake, and 949 6ul wheels with r888 tires on a 2004 r53 with 133k miles. But even still that was enough to pass e46 m3s, c6 base and z06 corvettes and even one zr1 with an obviously inexperienced driver. Gotta love the David and goliath effect of these super coopers.