1999 Volvo V70 XC--Cylinder Compression Problem--Valve Job?

[tkoegel]

I have a 1999 V70 XC. 71K miles, all the recommended factory service through the dealer that sold it to me new. We have on and off had problems with the check engine light, most of which were attributed by the dealer to a bad seal on the gas cap. Over the last six months, though, the check engine light began to come on more regularly, usually when the tank is half empty. At 65K, the dealer recommended a replacement of the "mass air flow sensor" to fix the problem, and that work was performed. At 69K, the light had returned and the dealer reported a Canister Purge Valve problem based on "diagnostics shows DTC 4308 EV AP System Leak". Dealer replaced purge valve.

On the return leg of a long (800 mile each way) trip, the check engine light went on and the car clearly began to miss on one cylinder. Initial emergency stop gas station diagnosed a bad coil on one cylinder. Flogged the car to the nearby dealer (this is not our home town), who seemed dubious but was too busy to deal with the problem. Bought coil, which of course was not the problem. Car now back at nearby dealer, who diagnoses a complete lack of compression in the number 4 cylinder. They are opening up the engine tomorrow, but best possible case seems to be a bad valve and worst possible case . . . well, who knows? It seems quite bizarre to me that a 71K six-year old car should require a valve job or worse. The dealer holding the car said, "oh, who knows what bad things California gas does to engines."

Thoughts, comments, or suggestions would be greatly appreciated.

Tom

[White850Turbo]

Wow, I've never heard of a whiteblock engine needing a valvejob, ever. I know the B230's need them if they're not taken real good care of, but never the whiteblocks. Perhaps you should consider other items such as the spark plug itself (cracked electrode) or maybe a faulty fuel injector.

[chevdiver]

I am having the very same issue with my 98 S70 GLT. The dealer can't figure it out. They are telling me they think it is the Oil Pump. In a different forum, I have posted my issue and a mechanic from Fla thinks it is a Fuel Pump issue. We tried replacing the o ring on the oil pump, but that did not work. Now they are replacing the oil pump itself. If this doesn't work either, then the fuel pump is next. If you get your issue solved before me, please post your resolution here. thanks.