Hi! I'm looking at a used 850 priced at 4950. It appears to be in good shape as to the body. But the engine sounds a bit noisy to me, kind of like marbles rolling around. Is this normal for a Volvo 20 valve? I've had one previous 850 and just can't remember if this was the case with it or not. Thanks for your help!

Volvo has had an issue with stickey valve guide seals. The solution to this is a synthetic oil though Volvo fought against this for a time. I had that happen on our '94 and Mobil1 solved it. There is also a chance that the problem is with the oil pickup in the sump. That requires removal of the pan. Good luck.

Could be one of the belt tensioners going bad. Can you tell where the noise is located? Bad alternator bearings can make a "marble" noise also.

my '94 850 (180k) makes minor marble noise from the injector nozzles when cold
and owner's manual states lifter noise for up to 15 min after startup is not unusual

My 95 850 NA engine is not noisy near camshaft, crankshaft or accessory drives at 122K miles. There are various other rattles and vibrations around the car. How about probing around with a tube or other improvised stethoscope to be sure where the noise really comes from? If you suspect internal problems with the engine feel around under the oil fill cap with your finger for accumulated sludge and also look at the cam lobes for burning/wear. Those might mean lack of oil changes in the past.

My 94 855T with 144 is doing the same thing. I switched to synth and that hasn't helped so I ordered new oil pump seals and will try that to see if the problem is oil starvation. If that doesn't do it I'll try 15w-50 synth then replace valve seals.