'88 900S head gasket?

The fact that the engine cooled down when you started moving does not suggest a head gasket, but there is no denying the milky white evidence, so what must (may) have happened here is that you have 2 problems... The original problem in the cooling system which caused the overheating and this then resulted in a head gasket leak between the water jacket and oil galley.

Do a compression check on the engine to diagnose the head gasket. You will still need to sort out the cooling system problem once you get the leak resolved.

My C900 was prone to overheating on her old radiator which had lost about 20% of its fins in the crucial central area. At a standstill this led to the needle creeping up quite high, but once moving again the airflow around the remaining fins was sufficient to cool her down.

Is your rad' OK? plenty of fins there? Water pump working properly?

10 to 1 a poor cooling efficiency led to the gasket.

I agree with Fred on compression check first, but FWIW I would budget time and money to solve both problems at once. One thing led to another after all.

Al

I agree. I did not mean to suggest that they should be fixed independantly.

in article 8KlBf.30250$jd5.2037@trnddc02, James Sweet at snipped-for-privacy@hotmail.com wrote on 24/01/2006 08:40:

Along with a compression test, have the coolant chemically checked for the presence of oil/petrol.

If it checks out okay and you have good compression, then I'd start to look at (a) the coolant and (b) the radiator. Do a full coolant change and flush the engine through. There are ways to do half the job, but do the full job :) Feel the radiator when warm (careful not to burn yourself) to see if there are any cool spots. Over the years, all manner of crap builds up in the coolant and has a habit of settling in the radiator. Especially, if you/former keeper has dropped in one of those Radweld products :(

Of course, it could be a stuck thermostat ... Still warm? Change the radiator. You'll be amazed at the difference.

Good luck,

Paul

Vart tog vägen vägen? SAAB : Nothing on earth comes close

in article BFFC24A8.6FF% snipped-for-privacy@blueyonder.co.uk, Paul Halliday at snipped-for-privacy@blueyonder.co.uk wrote on 24/01/2006 18:38:

Sorry ... Forgot to say ... If it does turn out to be a failed head gasket, then don't worry. It's not the big deal on C900s that it is on other cars. Perhaps drive the minimum you need to in order to have the various suggestions checked out.

Catch the job quick enough and it's literally, pull the head, change the gasket and pop the head back on with no need for all that skimming and strip-down. While the head is off, it's good to have a cursory look over chambers for signs of abnormal wear and impending failure :)

Paul

Vart tog vägen vägen? SAAB : Nothing on earth comes close

Pay special attention to the head in the area directly between the #2 and #3 exhaust valves.

Dave

Radiator looks fine, car never truly overheated, the guage just started creeping up and got about 2/3 up the arc rather than sitting at around

8:00 as it normally does. I agree that there may be two unrelated problems, though I was thinking perhaps the low coolant caused an airlock as she also mentioned the heater air got cool, I forgot to include that.

What tends to happen there? Cracks?

At this point I intend to do a leakdown test and beyond that I will likely just pull the head. The cost and time it would take me to find someone to do chemical tests on the fluid is not worth it when I have access to a full machine shop with all the tools needed to do the mechanical work.

The fact that nobody mentioned any real sticky points in R&R of the head makes me feel a lot better about the job, some cars I've done have been very easy (Volvo 240), others were an absolute nightmare (Porsche 924 Turbo comes to mind.)

Well, it's a high heat area, and there's very little head between the cylinders. I've seen erosion in the head there, and I've seen gaskets go specifically there.

Right, I'd agree. Chocolate Milk-looking oil is enough of a chemical analysis to tell you there's coolant in there.

The ONLY thing to watch out for is - don't drop the timing chain. Don't drop the timing chain, don't drop the timing chain, and whatever you do, don't drop the timing chain. Was this a B engine or an H engine? Because if it's a B engine especially, you don't want to drop the timing chain.

No, I don't want to talk about why I know that.

Dave Hinz

Hi James,

FWIW: I had some of that once, but only just under the cap on the dipstick. Started to worry, but couldnt find anything wrong. When I noticed it it was winter, and quite cold. Might have been condensation inside the filler tube, over quite a long time. Changed the oil, cleaned it all, checked some more, found nothing, and have never seen it again.

Ries.