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My 1992t conv. exhibited blown headgasket symptoms a few weeks ago: white smoke, coolant loss, mayo in oil, bubbles in coolant expansion tank etc... I brought it to an indy Saab shop and they confirmed my suspicions when they tested for exhaust gasses in the coolant. I had them send the cylinder head to a reputable machine shop for pressure testing, milling, and a valve job. The head was found to be sound and they took off .0064"

I got the car back a week ago after new headgasket and reassembly. Car seemed fine on the drive home. But the next day, after the first cold start, I noticed the same disconcerting hg symptoms. I thought I could chalk off the white smoke and water in oil as residual condensation. But I cannot think of a comforting explanation for the stream of bubbles out of the coolant return hose and the continuing loss of coolant. Any ideas as to why the new headgasket does not seem to have sealed the cylinders? The only things I could think of are a problem with the block or a micro crack in the head that the machine shop missed. Are there any other possible explanations for the symptoms that aren't semi-catastrophic?

The car has 126k miles. The car previously had the hg replaced around 95k. The car has greater than stock boost and fuel but is rarely driven hard. Thanks.
 

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It might be worthwhile re-torqueing the head bolts. Two torque settings followed by a 90 degree turn.
 

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I agree.

But - do you carefully slacken off all the bolts and then work through the whole torquing procedure; or do the bolts one at a time? I think my vote would be to do slacken them all off (in sequence).

eduggs said:
The car has 126k miles. The car previously had the hg replaced around 95k.
Are you saying the current headgasket has lasted 20,000 miles or that it has been replaced at 95k and then at 126k? Sounds like the latter...? If so then I am amazed the replacement gasket lasted only 20,000 miles.

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I think a retorque is worth a shot ok. 18 months ago, the "mechanic" I trusted to rebuild the engine left out the final 90 degrees angle tighten. You might want to ask the garage what torque procedure they used.

If you search for threads by me, you will see that Jim Methesene advised slackening and retorqueing each bolt in turn.
i.e., slacken the bolt, torque it through the 3 stages, move on to the next one.
And thats what I did, the head gasket lasted another year. I suspect its seal was compromised by me driving around for many hundreds of miles with only 60 lb/ft on the head bolts ( and I was running boost after the first hundred miles ).

Slackening all the bolts allows the possibility that the head will move - I don't like that idea. Certainly I found that after putting the head on, it was possible to rock the head side to side. The gasket is made out of multiple layers, and you'd run the risk of some of it parting company and staying on the head or block if the head moves.
 

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the turbo wouldnt cause bubbles in your header tank though, and highly unlikely to cause mayo in oil. I'd do as the others have said and re-torque the head bolts, even take off the head and put a new HG on. atleast that gives you a chance to inspect the head. if your loosing a considerable amount of coolant and its filling up your oil sump i'd act quickly and take off the head...again...i know the feeling :cry:
 

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it is always a possibility that if water cooled turbo and oil supply as well that you have a crack in the turbo casting, I admit very unlikely but not impossible S*1T happens, more than 1 way to skin a cat. re torque first, check compression ratios as well.
and good job you have'nt got the gm engine which has the oil/water rad in one, :nono; and when it fails ,quick mix, engine gone;oops:
 

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I would question the work done on the head. For one, why were the valves reground? It should only have been necessary to lap the valves.

Philb has a good point 'though I remember his troubles when the mechanic he used 'forgot' the final 90 degree torqueing procedure. When I did my HG and applied the final 90 deg it was damnedhard work even with a long extender bar, suggesting that without the 'extra' it's going to leak.
 

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I would do the re-topque as described, then if it still has problems I would do a compressoin test, cyllender leak down test and a coolent pressure test (engine warm) You could have a warped or cracked head.:(
 
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