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Discussion Starter · #1 ·
My 1992 CS Carlsson suddenly started to billow white smoke from the exhaust last night. Initially thought the turbo had gone but been advised that the turbo appears to be working ok - any suggestions would be greatly appreciated. If this helps, the couple of miles I drove before this happened felt like one time before when the wastegate on the turbo was stuck open.
 

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Sounds like the head gasket is away. A common problem with 9000s unfortunately. I've had 3 fail all around about 80,000 miles. Maybe I've just been unlucky, the current car has 75,000 on it. Hmm.
 

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what did it feel like?

Mine is billiowing white smoke but it's mainly within 10 mins of start up and I'm putting it down to the weather. What else would I experience if head gasket had blown
 

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A leaking head gasket can either allow water to leak into the oil (causing white deposits and evidence of water on dipstick) or oil leaks, or both.

Due to the very high pressure within the cylinders, exhaust gases always blow out. Water can only ingress into the cylinders when the engine is off and cooling, and the pressured water jacket may then trickle water into the cylinder/s. This causes a white deposit on the spark plug/s of the offending cylinders - so easy to check.

The effect is lumpy starting, which may last for one or two minutes after engine starts, until all water is vapourised and/or expelled out of the exhaust valve.

Not sure how water can cause 'constant' white 'smoke' unless it is leaking from the cooling system into the water cooled turbo, though.
 

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Sounds like the Head gasket, when mine went on the 900, it would use a pint to 10 miles, and left a hugh plume of white smoke from the exhaust below 2500 rpm, settled out above that, and blew bubble back into the water jacket above 3500 rpm.

When I took the head off, one cylinder was completely washed out. Also, when I drained the oil, it had 4 pints of water 1st, then the antifreeze and finally oil. It had separated the water from the antifreeze.
 

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a word of caution,if it is the gasket and you replace it,skim head etc.make sure you flush all oil/water from sump.use cheap oil and prop. flush,let car tick over for 15min. drain then repeat at least two more times.i flushed mine once only and three weeks later got gunge in oil pump,luckily relief valve came to my rescue/but i had to blast compressed air down oil ports to remove gunge.it caused me more pain than the bloody gasket.
 

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>>>Not sure how water can cause 'constant' white 'smoke' unless it is leaking from the cooling system into the water cooled turbo, though.

...Or unless it is a really bad blow, as in wrighars case!

Which should be pretty easy to find... and fast... or you nacker the engine cos water doesn't lubricate very well!
 

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Have you checked to see if any of your levels are going down, especially coolant? There's only really two things that would cause white smoke like that, brake fluid burning or coolant, try smelling your exhaust as burning coolant has quite a sweet smell. My car is doing this and I've tried nearly every check going, oil has no water in it, coolant has no oil in it but goes down fairly rapidly, there are no hydrocarbons in the cooling system. I've had to come to the conclusion that the head gasket has gone the only other possibility is the turbo, but i'm more inclined to think it's the gasket as the car is lumpy on starting. Once warmed up it is fine until it sits on idle for any time.

HTH

Neil
 

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On a closed throttle (over run)high manifold vacuum hence water can enter the cylinder on the induction stroke only needs a small amount then when throttle opened slightly large amount of white smoke until offending cylinder is cleared of all traces of water (this occurs quickly once the offending cylinder starts firing again. This happened on mine. Hence under power no smoke, on the overrun very little smoke, back on the power and clouds of white smoke!!
 

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One other possibility, if the head gasket is in fact OK it could still be a turbo oil seal. If the seal on the exhaust side is gone allowing oil into the exhaust, this will vaporize and create white smoke. Only burnt oil produces blue smoke apparently. I wouldn't think that a blown oil seal would stop the turbo from producing boost.
I'm still more inclined to suspect the head gasket though.
 

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Another possibility would be a cracked head. I had one go on an ageing 900i some years ago. No water in oil nor oil in water but some bubbling in coolant and resistance to cranking under starter.

Definitive test was leaving over night pulling spark plugs and cranking on starter.
Lovely fountain from No. 3 cylinder. Head was cracked between inlet & exhaust valves.
 

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HOLD EVERYTHING !!!!!!!!!
I recently came back to the UK for 18 months and brought back a 900 Aero. When it arrived I went down to London to pick it up from the shipping agents and drove it back to Stafford problem free. Over the period of the following week I had to do mods to the rear lights in order to get it registered. During this week it started billowing "WHITE SMOKE" and like everyone else on this thread was convinced that the head gasket had blown. I took the head off and couldn't find any evidence of any damage whatsoever. I took the opportunity of having the head overhauled nevertheless and put it all back together (with a new head gasket I hasten to add) and to my dismay it was still billowing white smoke!!!!! The next stage of prep for registering the car was to get it MOT'd. IT FAILED on exhaust emission of all things and this was very surprising to me because the cars that are shipped to Australia have stricter emission control than that on cars for the UK. The guy that MOT'd the car just casually said "just check your air-flow sensor mate", so I did and all I did was take it out and blew the dust out of it and GUESS WHAT....................NO MORE WHITE SMOKE!!!!!!!!!!!!!!!!!!! The MOT guy said that the emission readings were absolutely perfect. So, before you go and take your head off just take 5 mins to check the air flow sensor. It might just save you a lot of time and money.
 

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>>>> ...Or unless it is a really bad blow, as in wrighars case!

>>>> Which should be pretty easy to find... and fast... or you nacker the engine cos water doesn't lubricate very well!

Luickily, water seemed to be an OK lubricant.
Just as well really, as it was a 60 mile drive to get the car home (after I'd pushed the car for 2 or 3 compression strokes to empty the cylinder of water
as the starter wouldn't turn through the water).

When I changed the gasket, there was no visible wear in the bores or on the cam. Amazing really when you think that it was only water covering the sump pickup.
 

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Discussion Starter · #17 ·
Just to give you all an update on the problem. After the head was stripped down the gasket had corroded on cylinders 2 & 3. No damage to the head (....phew!!!!) and all repaired for less than £200. Fingers crossed.
 

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Yup, £200 was the price I got quoted by my Saab Master Technician to remove the head, drill out the manifold studs and replace the gasket. Bit of a trek (well an expense at least) though for most of you to get to NI.
 
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