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Possible cracked head gasket?

2001 Oldsmobile Alero, 4cyl, purchased in March with around 150k miles.

About a month and a half ago I topped off the coolant. 2-3 weeks ago I noticed the exhaust was intermittently throwing off white smoke. Not thick, opaque plumes or anything, but more like how your exhaust might look on a cold day. Being May though, I knew the temperature was not responsible. This white smoke would occur intermittently and usually stop after driving for a a little bit. Since the white smoke was not constant and the coolant levels seemed to be okay I figured maybe it was something with the EVAP system or the fuel mixture. On a hunch and as a matter of maintenance I put in new Oxygen sensors a few days ago. The next day my coolant light went off again. Since then I’ve put radiator stop-leak in the coolant and some STP “gasket rejuvenator” in the oil.

My theory: if the head gasket is indeed cracked, it’s a very small crack–small enough so that after the engine warms up a bit the gasket expands essentially sealing the crack. This would explain the intermittent nature of the white smoke and and slowness of coolant leak.

Thoughts anyone? Are there any other tell-tale signs I should look for with a bad gasket, if this indeed that case?

I saw in the store some stuff similar to stop-leak specifically designed for sealing head gaskets that involved draining the radiator, dumping this stuff in and running the engine for a bit, draining it out, and letting the car sit for a day before putting new coolant in. Anyone had experience with this stuff? If the head gasket is the issue would the combination of stop leak, STP, and this stuff prolong the life of the engine for the next year that I’m still in grad school? Or should I start looking for something else/attending church?

It's possible it may extend the motor's life slightly. Possible. Not a sure thing, but you can give it a shot.

If you either test, or get the motor tested, with a compression and leakdown test, that will point you more in the direction you're looking with regards to either a leaking head gasket or cracked cylinder. A good mechanic can give you pretty durned good results with those tests. It may not be as bad as you're thinking, but it could be.

So it's up to you. Go for it with the additives, or go to a real mechanic. Most here will tell you the mechanic, and while I agree, if you're only goal is to squeak a bit more out of it, the fluids may help. Maybe.


I’d get it checked, as chaissos said. I’d avoid adding any more stop leak to it. The more you add, the better the chances are of clogging up your heater core, radiator, or cooling system passages in the block.