I have a 2002 ford explorer awd v6 that uses a quart of oil about every 400 miles. I took it to the dealer, they checked the plugs which were clean, found no leaks, only told me that they do use oil. It only has 100,000 miles and the oil has been changed regularly every 5000 miles but oil turns black immediately after changing it. Pcv valve was replaced about 5000 miles ago. Any ideas?

 

Does it puff blue or leave drips when parked??

 

Some black smoke on acceleration but no drips.

 

Black smoke indicates rich burn, maybe washing down cylinder walls.
What is your LTFT??

 

I do not know. It is a stock 4l v6. the frustrating thing is Ford mechanics tell me it is normal for it to use oil but if that is true I will never buy another Ford. My previous 1992 explore never used oil. I would expect at the rate it is using oil to have oil on the plugs if it was rings or valve guides. I suspect it is an emission issue but nobody at the dealer has a clue or perhaps the reality is Ford doesn't want to admit they have a problem. Very frustrating.

 

We have a stable full of explorers with more than 360k and they only use less than a Litre between oil changes(10k,km).

 

Normal is not more than 1 quart per 1000 miles. Your case is not normal, and if the dealer is insisting it is, then they have some incompetent mechanics.

Any visible smoke indicates either a rich condition or that it is burning oil. Visible steam is normal.

The LTFT will indicate if the vehicle is running rich. As far as the oil consumption, it could be leaking valve guides, it could be leaking past the rings, a blown head gasket can allow oil to escape, or the smoke you see may be unrelated to the oil consumption and it could be leaking externally onto the exhaust (no drips)

 

Cadillac claims 500 miles on a qt. of oil is acceptable on the Northstar V8,.......However even 1000 on a qt. of oil on a Ford SOHC 4.0 seems excessive, 400 is BAD......Is it smoking on start-up? If it is, suspect valve guide seals.

 

Certainly not normal. My 4.6L with 110,000 mi. doesn't need oil added between 3000 mile oil changes.

 

change the PCV valve again, and get the right one.