I have recently bought a 1995/940 non turbo. The lady who had the car had all the records and it seems that the car had been serviced very well. Though for what I read in the invoices the mechanic has been taking advantage of this person. Anyway I took the head cover and found a very dirty engine head with carbon deposits almost like dirt. Do you suggest to overhaul the engine to clean it out? The car runs very well, but I have never ever seen an engine this dirty before and I am afraid tom drive now.

Did you remove the head or the just the valve cover. It would be rare if not impossible to find carbon deposit build up under the valve cover. Carbon build up occurs in the combustion chamber. It is thick, hard and crusty. You may be just looking at the normal discoloration and a bit of varnish build up of the cam and other components under the cover. Some parts will appear black. On a very neglected engine (talking about oil changes) there could be a build of a soft sludge.
If what you are seeing is just the normal discoloration, then drive it and enjoy.
--
David Hunter

Thanks for the info. I agree, but this is very estrange and something I have never seen. Like you say it would be impossible. It almost looks like someone delivery has put this junk in the camshaft. I am not driving this car until I get all the engine inspected and cleaned. I have the engine ready to pull it out of the car. I found an engine crane in Sams Club for $178. Unreal, we are doomed with China imports. I could not even buy the raw metal to build this thing for that money in the US. The story with the car is that I bought it because the owner had perfect records. Oil changes every 5,000 miles and few repairs. This problem did not occur in just a few months so if the car was maintained as the records say, the problem would have been noticed long ego and should have been corrected. The owner is now waiting on my findings to go and have a discussion with his mechanic.

Another pretty prevalent opinion around here (one which I may follow) is to simply rely on the higher detergent properties of synthetic oil to gradually clean the engine. Some suggest that flushes may even loosen "flakes" that might block oil ports. Mind you, Auto-rx may not qualify as a "flush" (I'm sure others better informed can comment on this).

The only functional downside of synthetic, is that in some cases, it can clean deposits from seals and therefore introduce/worsen oil leaks.


--
David Armstrong - '86 240(350k km?), '93 940T(270k km), '89 240(parts source for others) near Toronto

I am told that the best stuff, albeit a little pricey, for this situation is AutoRx. Learn more at www.bobistheoilguy.com

I've used Auto-Rx with good results in several of my cars.

In the '89 740 turbo, it cleaned out even the Silica (dirt) the first oil analysis showed. Then it generally improved scores on metals, too.

My Toyota Avalon, a 1996 with the engine notorious for sludging, it keeps it clean. The oil analysis report was glowing in its summary: A nice, clean Toyota engine"

I also do an annual dose of BG 44K fuel system cleaner and top end cleaner
--
'Can't understand why people abort Volvos, either' '89 740 Turbo, 122,000 miles

What are you calling the "head cover"? The Valve/Cam cover?

Maybe it has not had regular oil changes. If it is running well,
change the oil and drive it.
--
George Downs Bartlesville, Heart of the USA!