Excessive oil consumption, 2002 xc70 Cross Country

rja1 · Post by **rja1** » 06 Oct 2008, 17:52

Over the last few months, the cross country has been "burning" oil at a very high rate. As much as 4qts / month. The dip stick barely has any oil on it. There are no visible signs of a leak nor is there any black smoke coming from the exhaust pipe. I use synthetic oil so maybe that is not a surprise. I did notice this weekend a small build up of burned oil/residue on the engine near one of the spark plugs.
Does this mean the engine is shot or is there some gasket /seal leakage that could be repaired.

sony2000 · Post by **sony2000** » 10 Oct 2008, 15:55

If your not using Mobil 1, then start. If you are using Mobil 1, before you change it, do a Seafoam crankcase treatment. Then switch to an oil for high mileage cars. I would think you have too much carbon, on a good engine.

instarx · Post by **instarx** » 28 Oct 2008, 03:30

No smoke? It's gotta be going somewhere. Put a piece of clean cardboard under the engine overnight to see it there is a leak. If your engine has an oil cooler make sure the cardboard is under that, too. The leak may be internal - run your finger around the inside of your exhaust pipe - is it black and oily? If so, oil is in the cylinders and it's an internal engine problem. You should also inspect your sparkplugs and see if any are seriously fouled.

If the leak is external and you can't find where it is coming from there are flourescent dyes you can add to the oil that will glow under a UV light. I did this for my truck to find a coolant leak, but they are available for oil too. A cheap UV flashlight at a novelty store works as a detector as long as you're willing to hunt at night. (It's near Holloween, so they should be easy to find!)

You might as well try an oil for high mileage cars, but a gallon a month is probably too big a leak for that to fix, but it can't hurt to try. Personaly I don't think switching to Mobil 1 in your situation will do anything except empty your wallet - Mobil 1 is a darned good lubricant but one lousy repair tool. Anyway, until you find your leak you can use any oil at all - the long life of synthetics isn't needed if you are adding a gallon of new oil a month.

Sony2000 is right - a stuck or carbonized valve (or sticky rings) can also cause high oil consumption (usually with smoke, though). I'm not a big additive fan except in extreme cases, but that seems to fit here. You might try a seafoam treatment - it can't hurt and it may help.

What's the mileage on the engine?

bobsnow100 · Post by **bobsnow100** » 31 Oct 2008, 14:06

Check your PCV system. My 2001 xc70 used a lot until I cleaned it out. Your engine needs to breath.

rja1 · Post by **rja1** » 15 Nov 2008, 09:00

I had my mechanic perform a cylinder leak down test. All cylinders passed the test so i guess that means the engine is ok. The car has 112k miles on it and i recently had the oil changed. This time i put a high mileage oil in it.
Someone suggested i do a seafoam treatment. Can you explain what this is and how to administer.
thanks.

sony2000 · Post by **sony2000** » 19 Nov 2008, 17:03

Perform the Seafoam treatment just prior to an oil change. I believe there is a similar product in the high mileage oil but a lot less than, the shock treatment of Seafoam.

Checksix · Post by **Checksix** » 26 Nov 2008, 20:02

My vote is to have the PVC system cleaned or replaced. There are numerous posts on this forum and others about what a plugged system does. A real easy check for possible PVC issues is to pull the dipstick and check for out gassing there. If that is happening, then the PVC system needs repaired. If you have been running synthetic since new, then the probability of a plugged PVC is diminished, but with all the tolerance stack-up when building engines, there are a lot of differences between the same engines. Check the dipstick and let us know.

Jerry
01 V70 T5a