Over Pressurized Cooling System
So I've had a mysterious coolant leak for the last few months that I haven't bothered much to try & track down. Just top off the reservoir & move along. Well a couple weeks ago I decided to pressure test the system & see if I could track down the leak. Car off, pump the tester up to 15psi & let it hold for 10 minutes. Didn't budge. So I relieved the pressure, then hooked the gauge back up. Started the car up. Within 15-20 minutes she'd spiked up to 29psi before I finally had had enough & wasn't trying to push it any further.
It looks/feels like a standard head gasket blown. But I'm just not trying to dive into that without doing a little more research. It's got 188k on it, I just did the timing belt/water pump two years ago & have never had any issues with over heating.
I'll do a compression test before I start the tear down just to check everything else. I've already got my head gasket kit & new head bolts sitting here waiting for me to start. But I figured I'd check in & see if there's any other (far flung) idea that might be the cause.