CO951

I suddenly started getting white smoke today. It is much worse after idling. (More water getting in under high vacuum?) It still builds boost and runs smooth, but I haven't pushed it since it happened. There are no signs of cross contamination in the oil or coolant, but I was near home and drove it less than 2 miles since it happened. After it had cooled for 3-4 hrs I ran it for less than a minute and then there was a lot of smoke/steam coming out when I removed the oil fill cap. Is it the head gasket? Is there something else I should check?

Paulyy

put your finger in the water and see if you can feel movement from cylinder pressure. or close the cap and crank it a few times. take the cap off and if there's pressure, you've most likely done the head gasket.

refresh951

Does the exhaust smell like anti-freeze? Sure sounds like a HG. When was it last replaced?

CO951

I tried to jump out of the car and smell the big cloud of smoke, it's a little windy and I couldn't tell. As far as I know it's the original HG and I have about 135k miles on it, all at stock boost.

refresh951

The stock HG deteriorates over time due to coolant exposure.

onspeed

Pull the plugs and seen if one a lot cleaner than the others.

Dougs951S

pull off the coolant pressure cap after the car has cooled and then let it idle while you watch for bubbles rising up. Sounds like you popped the cork so to speak.

CO951

Well, after snow yesterday, I got a chance to run it a little today. I let it run a few minutes, some at idle and reved it some, but there were no bubbles in the coolant tank. I will pull the plugs tomorrow to check them.

CO951

I pulled the plugs today and they all look the same. I don't know if the fact that I've only driven it 2 miles and idled it a little since it happened is when I'm not seeing any cross contamination or a clean plug. Do I need to run it more to see I can see the effects or are there are other tests. Or are the symptoms I described pretty clear on there own?

MooreBoost

Do a coolant pressure test or a leak down test

Tom M'Guinn

135k is a lot of miles on a stock head. Hard to say for sure based on limited internet info, but at 135k miles you wouldn't be crazy to pull the head and get a good valve job, with a fresh new gasket. Have you noticed any coolant overflow after running it hard? See some diagnostic tips in the HG replacements guide in the link below this post. White smoke can also be oil in the turbo, but if you are seeing steam come out the oil filler, it sounds like the head gasket or the oil cooler seals. If no mixing at all then more likely the HG.

CO951

Thanks, that link was helpful. If I understand correctly I wouldn't see the white smoke with oil cooler seal problems. From reading it sounds like I should drive it a little more to try some of the tests and then if it still isn't clear, try the leakdown and coolant pressure tests.

CO951

I got a chance to drive it a little more today and get on it hard. It will boost, but doesn't reach full boost. There was no sign of the coolant being pressurized and overflowing when under boost. There is also still no sign of cross contamination in the oil or coolant. There is still a lot of smoke/steam coming out of the oil cap. I'm not sure how to do a compression or leak down test.

So to summarize: I suddenly got large amounts of white smoke out the back, but still runs pretty well. It will boost, but not get to full boost. I don't seem to be loosing any coolant under boost and nothing significant otherwise. There is no sign of cross contamination between the oil and the coolant. I get steam/smoke coming out when I remove the oil cap. Could this be anything else besides the head gasket?

ehall

A HG failure can be VERY small, and slowly get worse. They don't all just go POW! Infact, if you pull the HG, you may have to have an expert actually FIND the failure. I sent a set of pics to Chris White. The HG looked pretty solid to me and 3 other mechanic friends, (ya know guys who get paid!). Chris saw it in the second pic. Sometimes they just burn through slightly and that will do it. Go easy on the car until you know! At this point your whole life should be about not scoring your cylinder walls, until you find a valid other reason for the issue!

onspeed

sounds like the initial symptoms I saw when my HG went bad...