Overheated on track - now what?

[infernosg]

Originally Posted by Pete_89T2

I forgot to mention that I remove the radiator cap after the coolant is at operating temp and circulating thru the engine - this helps avoid most of the spilling, since once it's all circulating, the level in the rad should drop a bit. But yeah, if you remove the cap while its still cold and run the engine with the cap off after just filling the radiator, lots of coolant will barf out. Just use a thick rag to keep from burning yourself, crack open the cap to the first stop to release the pressure, let any excess coolant bleed out then remove it all the way.

I did this at the track before heading home and a good amount of coolant came spilling out. Kind of like a slow geyser. I didn't leave the cap off long enough to see if it was going to stop though so maybe that's normal?

So more updates. First a picture of the radiator cap. The tear is hard to see but it's "inside" the "ear" of the cap toward the bottom:





I managed to rent a cooling system pressure tester from the local Autozone as well. First the good news. I checked the radiator cap - it opened at the appropriate 0.9 bar (about 13 psi) but it would not hold any pressure above ~9 psi and even then it still fell slowly. Outright, this makes me believe the radiator cap is dead so there's at least one thing.

Next, the not-so-good news. I attached the pressure tester to the radiator and pressurized the system up to 15 psi. Within 10-20 minutes the pressure had dropped to 14 psi or so. I brought the pressure up to 20 psi next to see if it fell off any faster but it dropped ~1 psi in about the same amount of time. I did not see any external leaks, so something's got to be off internally. Then again, perhaps the seal on the tester wasn't perfect and the engine's fine as I'm not detecting any gas or exhaust fumes in the overflow bottle or radiator