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Burnt Valve? Volvo '95 850 oh deary me!

Would like some help to determine what to do. Car was acting very balky at startup and running rough. Has 106 thousand miles, no problems before this (Bought used 3 years ago). Mechanic said they tested it and one of the valves is burnt "low compression #2 cylinder") and we need to have a valve job, probably cost us about 1000.00 Yikes!! When we called him back today to ask what were the compression numbers he said that they had not entered them into the computer. So, my question is--how important is this "valve job?? Is this something that is going to hurt the car not having it done? Don't know that I want to spend a thou on this right now--Can we wait till after house heating season in Vermont to do it (like the Spring, if it ever comes here?) Anyway, all advice greatly appreciated--we really know very little about this and definitely need to learn--fast!! Thanks

Reply to
trish5
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1000 seems awful high for just a valve job. I had an entire rebuilt head put on my car for under 600$. Get another opinion from another mechanic.

good luck

RS

Reply to
Rusty

Wouldn't hurt to have it checked out by someone else, or at least shop around for a valve job but this doesn't sound too out of line if it is the problem. The valve will likely burn worse and could damage the seat or head itself if run like that. Also I'd be worried that whatever caused the valve to burn (often a partially plugged fuel injector) will keep that cylinder running hot, which can ruin the cylinder head or burn a hole in a piston.

Reply to
James Sweet

You need advice from one of the gurus here, but IIRC the 850 is susceptible to sticky valves caused by prolonged operation at relatively low engine speeds. This will cause the symptoms your mechanic is reporting - low compression on one or more cylinders, but the valve is not actually burnt. The recommended fix is *much* cheaper than a valve job, and involves a few minutes running the engine at high rpms in a fairly low gear - with an oil change immediately before or something like that. My recollection is that the condition can reach the point where the engine will not start without a lot of cursing and drama.

Hang tight for one of the guys who knows what I'm trying to say ;-)

Mike

Reply to
Michael Pardee

So should I occasionally take it out for, um, MORE high speed runs?

Reply to
Franz Bestuchev

Actually, what you're describing is cause of the problem and the first stage of symptoms. However, the first stage doesn't last too long, any leakage is deadly and a chunk of the valve burns away. Eventually the leak gets so big the cylinder stops firing, then the unburned mixture is dumped into the catalytic convertor, possibly overheating and destroying it. In the meantime you'll have misfiring and very poor mileage. This is not a job that can be put off.

Reply to
Mike F

Mike F.,

Are you saying this doesn't sound like a candidate for the on-the-road method and that it needs the actual valve job?

Mike

Reply to
Michael Pardee

It can't hurt to try, but usually once the valve doesn't seal for any reason, a sliver burns out of it quite quickly. I've seen several on the 850 engine, both turbo and non turbo.

Reply to
Mike F

Ah - would a borescope tell the story (maybe the mech already did that)? It sounds like the safe thing is the expensive thing.

Mike

Reply to
Michael Pardee

Thanks, all--we're bitin' the bullet and having the job done--in the last two days it has relllly had trouble starting. Great site for information, so glad I just found it t

Reply to
trish5

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