My boss has an 850 (non turbo) that is using a lot of oil thru the valve seals (guides?)The dealer in his town told him it was not worth fixing - too complicated.
So the question is - how bad expensive can this be - and is it something that will come back to haunt you - by not being fixed right?

I just want to keep him in the Volvo family.

Thanks for any help,
Andrew in AL

91 940T - 195K
94 940T - 125K

Ive been driving volvo for 25 years (850 for 3 now) and have never heard of an engine needing valve stem seals! Are you sure its not a BMW?

To the professional Volvo mechanics out there . . .

Assuming the valve seals are the problem here (big assumption, but let's go with it), would a technique as I describe below be worth it.

In order to reduce the complexity of pulling the head in order to replace the valve seals, could one simply remove the cams and then, one cylinder at a time, place that cylinder at TDC, lock the crank to prevent engine rotation, pressurize the cylinder with compressed air (through the spark plug hole), use some fixture to compress the valve spring retainer, and replace the valve guides this way without pulling the head?

The biggest problem here would be to make the valve spring compression tool. But assuming you could mae something like that, would this method work?

(BTW--putting the engine at BDC would be safer and not require locking the crankshaft. The problem is, however, if a valve were to "drop" with the engine at BDC, you'd have to pull the head in order to recover.)

I have yet to see a Volvo engine with bad valve guide seals so I'd doubt that guess. It's more likely a clogged flame trap or clogged hoses to the flame trap (PCV system) that'd be causing excessive oil consumption.

How often is the engine burning 1 qt of oil bacause it's not considered excessive unless it's less than 1 qt per 1000 miles.

If the PCV system is known to be good, than have the engine checked with a cylinder leak down tester to try and determine if it possibly has bad rings. Valve guide seals usually do not cause excessive oil consumption if and when bad but might explain oil smoke when started cold or after adding oil as that's when the oil would seap by those seals, not under full throttle.

Flame trap on an 850 ??? Did not know there was such a thing. I hope that it is easier to get to than the one on my 740 was.
A hint where it might be would be in order.

Thanks,
This may get me a promotion. Joking - of course.

Andrew in AL

In non-turbo 850s, it's located in a housing in the large air intake hose (between throttle body and MAF meter) just in front of the throttle body and towards the firewall side. It has two hoses going to it, one's a vacuum hose and the other's a larger PCV hose that goes to the breather box under the intake manifold (just like your 740).
If the flame trap is clogged and/or any of those hoses, you'll have excessive blowby.
I've seen several older 850s where this has been ignored previously and oil was blowing from everywhere (even oil fill cap with a new seal) and once the PCV system was repaired, the engine was dry as a bone afterwords.

If the flame trap housing is eroded away and/or you're unable to remove the old flame trap, get another housing as they're only a few bucks. Make sure that the vacuum supply (hose and vacuum T nipple) is good and that the PCV hose to breather box (including breather box) is also not clogged (blow through it).