Going the distance with a 1994 850!
Evidence Volvo’s Inline Five is (Near) Bulletproof
An MVS member’s findings upon taking his engine apart at 200k miles
For sometime my 1994 850 NA had been burning oil. Even though power was good, I thought that it might be valve seals or valve guides and kept putting off a head repair job. Until one day, driving at 60mph, engine started misfiring.
To make along story short, a small piece of an exhaust valve on Cyl3 broke off. We took the head apart and found that actually the seals were bad. Probably the valve broke due to a piece of carbon build up that got on the way when the valve closed. For an engine this old, running with a 25% ethanol content gasoline, the amount of carbon was comparable to much lower mileage engines. No oil sludge of any kind, cams are perfect, valve lifters are perfect. Very small amount of carbon like material on oil passage ways. Head gasket looked like new. Coolant passageways clear and clean throughout.
We decided to take pistons out. Oil pan also clean, no sludge, just the brownish varnish like inside. O-rings looked perfect. Pistons look perfect after clean up. Rings appear to be perfect also, although I decided to replace them, since I found some carbon build up on them. Cylinder walls are in exceptional good shape, no visible wear, and still have the polishing markings. No ovalization either. Piston rods and pins look new, as the crank does. Only significant finding was that one of the piston rod bearings had some scratch markings on it that could be felt if one passed the fingernail on it. Water pump, still the original one, has no leaks and no play. Looks new, but I will replace it anyway.
Having taken good care of this car since new, however exposing it to long traffic jams in Sao Paulo with long, extended idling times, I concluded that after we put everything back with new rings, rebuilt head, and new piston rod bearings, and new OEM water pump, it will be good to go for many years more. I was impressed on how wear was minimal.
Lessons from 200K miles on a 1994 850 NA
Last Updated on August 19, 2020
