Surprised I made it almost two years, but it appears either the head gasket is leaking or I finally experienced the dreaded block crack.
I was driving it pretty hard on some of my favorite mountain roads this weekend. Everything was fine, car was running great. I crested the hill and started on the downhill stretch.
About a mile in, I got a low coolant light. Temp gauge was in the middle. I just shut if off and coasted down probably 3-4 miles to a house and they let me fill it back up with water. It was pretty apparent that the coolant had been pushed out of the cap. Probably took a couple quarts.
Drove home no issues, didn't think much of it. I had put a lower pressure cap on it at one point, and I just chalked it up to that. I did put a new factory pressure cap on it at this point.
Drove it to work the next day and it was fine. Went out at lunch, cranked it, and got a low coolant light. Not cool. Topped off, made it halfway home, low coolant light again. Topped off, drove home.
Once I got home, I let it sit to cool off a bit and then put the coolant level at halfway in the tank. I put the cap back on and let it get up to temp, holding revs at 25000-3000. I noticed that while doing this, the coolant in the reservoir would get pulled down to below the min mark, triggering the light. Cracking the cap and releasing pressure would allow the coolant to bubble back up to the middle.
I drove it around with the cap loose in an attempt to maybe work out some air bubbles in the system. Drove fine, went back home, went to bed.
Checked the level before I left for work, looks great. It burbled/missed ever so slightly when I cranked it. Got to work, level looks great. Drive home for lunch, again it burbled/missed for about 2 seconds this time. Warmed up, give it a solid 3rd gear pull to about 5000, and the coolant light comes on a couple miles later.
Same story. Pull over, vent some excess pressure, coolant returns to normal level. Drive the next couple miles home, and the low level light comes on pulling into the driveway. Again, vent pressure, level comes back.
So anyway, I picked up a combustion leak tester and some fluid on my lunch break. The car is sitting at home cooling off, I'm going to confirm my suspicions when I get home, and I guess start pulling stuff apart. I'm hoping it's just a leaky head gasket, but given the track record of P2Rs, I kinda doubt it.