Decided to reduce the Volvo fleet from 4 to 3 and put the 1997 850 GLT LPT on the market. Got several calls. Beautiful body, cold AC, etc. Engine still runs strong with no apparent problems or hesitation.

However since battery was unhooked to charge several days ago, the codes weren't resetting and in CA, it couldn't be smogged until the car went thru its cycle. Hasn't had a check engine light in years. But it wouldn't go thru the cycle, even following Volvos recommended driving pattern. So bit the bullet and took it to the dealer even though they wanted an umbelievable $480 to put it on rollers and try to reset the codes.

Next day dealer called and said to donate the car. The codes won't reset because of a blown head gasket, even though still no codes showing. I don't pretend to understand but I cant sell it if it won't be smogged. So I either donate or drive until it quits or part it out. "Sad day in Mudville." The only good news: the wife didn't really want to part with it. She has had it since 1999 and took excellent care. Still drives much faster and sportier than our 850 and two 940s.
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1993 240 Classic; 1993 945 Turbo; 1992 944 Turbo; 1997 850 GLT

Sorry about the head gasket.

Even California acknowledges the 1996 & 1997 850 engines as never being in 'ready' state. This is a documented problem, and CA is supposed to give the cars a 'pass'.

The dealer should have known that they can not get the computer to get to ready mode. Bad dealer. Bad testing station.

BTW, do you use regular gasoline. I have this very unofficial theory that cars that are run on regular tend to have destroyed gaskets. The low octane gasoline burns hotter and sooner than premium, heating up the gasket close to the engine and causing a leak??????????????

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My name is Klaus and I am a V♂lv♂holic

I read what you said about lower octane gas possibly causing hotter firing and blown head gaskets. I have to ask: is the engine's temperature gauge not sign enough to know whether or not your gas is burning too hot? In other words, if my engine temp never goes past half way, how can it be so hot as to burn a head gasket?
Thanks.

Cylinder temperature has little to do with how hot the antifreeze is. The antifreeze is continously cooled, the pistons are not.

A hot side to a single cylinder can not be detected by the temp gauge. The turbo engines have oil sprayers to cool off the pistons, not sure about NA engines.

Most head gasket failures happen on either side of #3 piston, the hottest part of the engine. Of all the pictures I have seen, it appears that the gasket is burned away on the piston side and worked it's way outward or toward another cylinder.
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My name is Klaus and I am a V♂lv♂holic

Well, that's disconcerting. It's odd to know that a head gasket could get burned without having any clues it was happening. I guess for no other reason that's a motivation to use higher octane fuels.
Thanks.

If you use premium you should also notice a performance increase and maybe better gas mileage...:)

I stepped up to premium and have enjoyed a slight performance increase...but the mileage is still right around 27 mpg.

Maybe not a bad theory if you find the gasket to be burnt from the combustion chamber outward. After all, low octane detonation can burn valves which are harder than a gasket. And detonation is not always audible.

For what it is worth, a head gasket can fail without any dramatic cause.

Our '95 854 base had its head gasket fail at 97k. Upon disassembly it was found that part of the gasket corroded away. The car had never been overheated or had any other troubles.

When we purchased the car in 2001, I purchased aftermarket insurance from AUL (sold by dealer) The car had 1000 miles left on a 4 year, 48K policy.

They paid $1800 to fix the car.

We drove it until last month and 165k.
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'96 855R,'64 PV544 driver, '67 P1800 basket case, '12 XC70, the first three are mine, heh, heh, 525,000 miles put on 10 bricks