Coolant leak

iGuessImCool · Post by **iGuessImCool** » 25 Dec 2019, 15:38

Hello!

Trying to figure out a coolant leak. From what I’m observing, the coolant leak is external and my car has no issues with overheating. I have seen the coolant overflow in the overflow tank, the coolant will expand and come out the overflow reservoir. I’m not sure where the extra pressure is coming from. I’ve replaced the thermostat 3 times and the tank once. I’ve relieved pressure a few different occasions, with the heat on full blast and what not but I’m still coming across this issue. Any ideas?

Thank you!

jennysass · Post by **jennysass** » 27 Dec 2019, 16:17

Did you try the UV dye yet? Suck out enough coolant (Turkey Baster works well) to keep on min line, power wash engine with some degreaser, add dye, drive around slowly, check w uv light, drive fast, check again.

Post by **June** » 27 Dec 2019, 17:00

Perform a combustion gas test. You probably have a bad head gasket. Apparently the P1 cars are prone to head gasket failure. Just went through it with a 2007 C70. In our C70 the gasket failed in a way that allowed pressure to enter the cooling system, but no coolant into the cylinder or oil. Same high pressure pushing coolant out of the tank symptoms you described affected our car. It's a simple test and you'll find out for sure. June

iGuessImCool · Post by **iGuessImCool** » 28 Dec 2019, 18:00

Hey June, what was the condition of your head gasket when you replaced it?

Post by **June** » 28 Dec 2019, 19:28

It was just a minor breach I think #3 cylinder. The pressure from the engine running could pass, but the coolant pressure was not enough to pass the other direction. In time it would have completely blown according to the mechanic. Both the head and block checked good without warping. Apparently this is not uncommon for these cars. Ours is a low mileage dealer maintained car. The dealer fixed it at a high cost. I'll look at the ticket and see if he mentions the cylinder that had the problem. The mechanic said it was the usual place they go. I completely trust him as he worked on my mother's cars before I was a teenager at that same Volvo dealership, that's over 40 years ago. June

Post by **kallekula** » 29 Dec 2019, 02:16

Buy one of those cheap kits you pressurise the coolant system with from harbor freight.