Air in Coolant System?
 

If one had an air bubble in their coolant system, how much coolant might one expect to see "burped" out after some spirited runs at a track day?

I had a sub-optimal experience at the track, after getting flagged off for mechanical problems, I realized the coolant was most likely coming from the overflow valve.

I let the car cool, and added a couple of gallons of water, let it sit, and nothing was leaking. Warmed the car up, and went back to the track, and sure enough, after some more spirited driving, it started burping out fluid (now mostly water).

Again, it took a few gallons to fill it up. I think all told I probably put 5 gallons of water in.

Important to note, at no point did the temp gauge read over the "8" on 180. The car did not overheat (mostly because as soon as fluid escaped, I got off the track & cooled it down).

Also, after the 2nd refill, I babied it all the way home, stopping to check level a few times, and it seemed to be fine - a little overflow at one point, but I think I overfilled, so not terribly surprised. Made the 90 mile trip home, without an incident, and took the car in to my guy the next morning.

Other things to know, I had the water pump & a hose replaced a few weeks back, so obviously the coolant was drained / refilled...

Is it possible that air in the system can cause that kind of dumping?

Either air or overfill but I would think overfill would just spit out what expands past full.

Heater works well? Elevate just the rear. See if air comes to resivouir.

Would you believe it's the coolant pressure release valve failing? That's the diagnosis. They want to replace the reservoir as well. I'm inclined to believe it, I just don't want to pay the piper! Crud, this is an expensive year.

Good thing the wife got a nice Mother's day present, or I'd be in the doghouse.

Are you going to do the coolant tank yourself? It will save you a lot of money, but there is a high cost to be paid in blood and bad words.

If you're going to tackle it, read all the previous threads on the topic and make sure you have the right tools before you start. Read Pedro's DIY. It's not a job for the faint of heart.

Tools: the usual wrenches, sockets, pliers, and screwdrivers, , long reach angled needle-nose pliers, hose picks, remote hose clamp tool, inspection mirror, floor jack, jack stands, Airlift vacuum evacuator with appropriately sized air compressor, fender covers.

Replace the sensor and the cap while you're at it.

Yeah, I've seen the posts. Definitely not up to doing it myself.

I did the first half of that job this weekend (tank removal). It would be more fun to perform a root canal on yourself.

Could start with just the o-rings under the pressure relief valve.

Or just a new valve, which comes with the rings.

Just closing the loop on this one (preliminarily, anyway). The tech pressure tested the system, and the release valve was blowing out at very low pressure. He replaced just the release valve (saving his knuckles, and me the costs of several hours of labor), pressure tested the system, and it's back up to spec. He said he couldn't tell if the tank was original, but he suspected not because it's in good condition with the exception of the faulty valve.

Fingers crossed, the next track day will be the true test -- on the streets no problems.

He also replaced all of my "Non-Porsche Authorized Hose Water Coolant" with the good stuff.

Just a comment. I used my older compressor with a 14 gallon tank. I had to make two passes with the Airlift but was able to successfully get the dial up to 25 where it belongs. By "passes" I mean run until the tank is empty, close the valve on the Airlift, uncouple the compressor hose and let the tank refill, then repeat.

The same thing happens when I blow out my garden sprinklers in the late fall.