1998 Volvo V70 XC Q&A

1998 Volvo V70 XC Question: Turbo burning oil

I have a 98' V70XC I recently purchased. It has 155M miles. It runs good except that it occasionally burns oil and I think coolant as well. I removed the charge air tubes and I did find a good amount of oil inside, and even in the tubes coming out of the intercooler heading in to the intake manifold. I suspect that the oil pools somewhere then gets sucked in and burned. Looks like I need to rebuild the turbo? Are these water cooled as well? -
Answer 1
The turbo's are water cooled. It is normal to have some oil in the intercooler pipes, so it's hard to say if this is bad enough to warrant a turbo replacement. What do you mean it "occasionally burns oil and ...coolant"? -
Comment 1
Most of the time, it does not burn any oil or coolant. There is really no pattern to when it does it. When it burns oil and/or coolant, it seems to do it for short time and then like someone threw a switch, it stops. I would suspect rings or valve stem seals, but if they were bad, the problem would not come and go like it does. It also runs too good to have poor compression. That is what makes me suspect the turbo. -
Comment 2
What is leading you to believe it is burning oil and coolant? -
Comment 3
The blue smoke is the obvious sign for the oil. You can smell the coolant when it is burning it and the exhaust never stops producing steam, even after a run on the X-way at 70MPH. It's not using a great deal of either fluid, but the signs are obvious. I would suspect head gasket, but there is no contamination in either the coolant or oil. I also pulled the plugs and all are nice and clean. I would think a head gasket would not produce the problem intermittantly either. -
Comment 4
It is indeed a strange situation. I drove the car on a 250 mile trip, mostly at highway speeds. When I started out on the trip, it smoked badly for about 10 minutes while driving on surface streets. Just prior to getting on the interstate, it stopped all smoking and ran like a top the rest of the trip home with no issues. Two days later, it started smoking again, what I suspect was both oil and coolant. Blue smoke and the smell of burning coolant. Only for a about 6 or 7 minutes and then stopped abruptly. Ran fine and clean. Does not smoke at all when started cold. Just weird. I have been repairing cars on the side for 20 years and I've never seen anything like this. But then, most of the cars that I work on don't have turbos either. Trust me, I wish it were something else. -
Comment 5
When a headgasket starts to leak, it can be intermittent, but it would more likely happen cold vs. a hot engine. As the engine heats up the leak can be sealed from the expansion of the metal block and heads. The blue smoke is a problem, and this can be from a plugged PCV system or the Turbo as you mentioned, but also from valve guides and/or piston rings. I would get the cooling system checked for hydrocarbons, if there is a headgasket leak, there will be measurable hydrocarbons in the coolant. Shops will test this with the same tool they use for checking tailpipe emissions, or with a chemical test that reacts to the hydrocarbons. This needs to be ruled out before going much further. I would pull the intake air boot off the turbo inlet and check if the turbo impeller has any radial movement, you should have a little, maybe 1mm max!. The turbo has oil and coolant in ti, and if the body was cracked, or the bearings worn, you could get both burning in the exhaust, I haven't seen this before on these turbos, but it's conceivably possible. -
Comment 6
Thank you! This all make great sense, especially the crankcase ventilation. I have a friend who owns a European auto repair and dealership and he told me that these engines had a particular problem with crankcase ventilation. So much so, that the crankcases can build pressure to the poing of pushing oil out many seals, including the main crank seal and of course the turbo seal. (I would just take the car in to him, but he charges too much!) I did look down the neck of the turbo and saw quite a bit of oil. I pushed a rag down there and let it sit for a few minutes. When I pulled it out, the rag was pretty saturated with oil. I then ran the engine for a while and and no additional oil accumulated, so I am going to take a close look at the PCV system. As for the coolant burning, that doesn't seem to be as much of a problem as the oil and it may just be my imagination. It's not like I've added a gallon of coolant. I just smell what I think is coolant. Perhaps it's just the cat converter trying to digest the oil. Thanks again for the help. You've been great. -
Comment 7
Bret- Looks like I found the problem, at least I hope so. I took the intake off and then removed the oil trap. The bottom inlet was completely impacted and the top inlet was not far behind. Plus, the PCV tube that runs back to the turbo intake was broken in about 3 places and it too was plugged up. I went down the Volvo dealer and they had all the parts that I needed. They were even less expensive than the independant parts shop. I'm about half way done with putting it back together, but I think that this was the problem. Thanks so much for your help. Brian -
Answer 2
Oil cooled only. I have 01 v70 t5 with 149000 I getting blow by oil like you say I am going through half gaurt of oil every 1000 miles, I been checking IAT & MAP Sensors in the intake tube to make sure they are not full of oil so far so good I'm not blowing any smoke even on kickdown WOT on freeway, your going to have some blow by with higher mileage. If your not hurting sensors or blowing smoke let it go, unless everything has to be perfect like me, rebiuld or replace the turbo, I will be soon. -
Comment 1
I sold this car already, however it turned out to be the PCV oil trap. It was totally impacted. I changed the oil trap and all of the hoses and the problem stopped immediately. I sold the car to a friend and to this day, it's running flawlessly. Someone down the street owns a similar car and his started doing the same thing. We took it apart and sure enough, the oil trap was totally plugged up. Really stupid design... -
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