Help! Did I just blow a head gasket?

whoa · Post by **whoa** » 31 Jul 2014, 18:26

Driving up a steep mountain pass, with the temp needle perfect the whole way, the low_coolant light comes on. Coolant is coming out rapidly under the expansion cap. The cap and tank look fine. I toppled up with water and made it to my destination, but it kept happening, a always with the rock_steady 3 o'clock temp gauge.

I did try to burp the hose.

I can hear boiling.

I am on vacation in Lee Vining California...

Thanks for any help!

Mark

whoa · Post by **whoa** » 31 Jul 2014, 19:27

Update! When I squeeze the hose with cap on, I hear the air escape out of the cap. Bad cap, right?
Mark

RSM-GA · Post by **RSM-GA** » 31 Jul 2014, 19:33

Thermostat stuck closed?

Post by **erikv11** » 31 Jul 2014, 21:11

Bad cap! Replace it, makes perfect sense that it is the problem.

Post by **rspi** » 01 Aug 2014, 02:50

After you replace the cap, try NOT to open it when the car is hot/warm. Top off the system before you start the car.

Post by **cuhfs** » 01 Aug 2014, 05:32

How about a radiator cooling fan relay failure. Overflow cap failure not so common... fan relay failure. When you were driving faster the car cooled itself. Slow up hill it overheated.

Post by **erikv11** » 01 Aug 2014, 08:56

Possible, but with a bad cooling fan relay you expect the car gets too hot and the temp climbs, then it overheats and dumps coolant. Sounds like it is dumping coolant under normal operating temps.

Overflow cap failure is very common, especially if it is an older (gray) one or anything aftermarket.

whoa · Post by **whoa** » 03 Aug 2014, 19:49

Back home in SF now, after a nail-caused blow-out coming back over a different twisty, cliffy mountain pass (the first was Sonora Pass, the second Tioga). Not my trip for car luck! Thankfully these cars have good manners with blown tires, or I'd be in the newspapers tomorrow: "Local Man Drives off 1000-Foot Cliff in Well-Maintained Volvo / Idiocy Suspected".

The cap (black, aftermarket, which replaced a green one, I forget how many miles ago--50K?) was indeed the culprit. What looked, on Thursday night, like the big problem was getting a new one in time to get me home on Sunday, because even express mailing something to tiny Lee Vining wouldn't have gotten it there before Tuesday---it's pretty remote. However, the local mech has a supplier who sends drivers daily up and down the California East Side, and he managed to get a new cap the very next day (the same crew---Shell of Lee Vining---put two new tires on my car within 20 minutes of my driving in!). But I actually beat them with the cap: the morning after I limped in, a woman who was part of our rock climbing adventure called to say the she was on her way, now driving through Oakdale, CA. Oakdale! To many, the boonies, but still, civilization! A quick call to the Autozone there scored a cap (a green one in a NAPA box; the mech's cap is black, like the one that broke; the green and black ones don't even look alike on the underside). I went from thinking I'd have to junk my car back to square one in no time.

I now have a a spare cap, which I definitely wish I'd had in my oh-s#%t kit before. Only $10 and it's a potential vacation-killer or car-killer if you're not careful.

Thanks for the help, all!

Mark

Post by **rspi** » 04 Aug 2014, 07:30

Mark, get a green Volvo cap and throw the other two in the trash.