[porsche959]

2006 n52 6sp

burns a quart every 400 miles when using 0w-30 penzoil.

burns a quart every 700 miles when using 0w-40 castrol.

could this be a vcg leak? I am not getting the usual smoke burning on catalyst, only occasionally if i corner hard.

am seeing some oil on the oilpan, but not sure if its dripping from vcg.

possible ccv valve gone bad?

thanks

[marvinstockman]

If you were leaking that much oil, oil would be everywhere. Now your vcg may be leaking, but as I said, not that much oil.

Also, in normal driving, and if the cat is hot, it will burn the oil, and you won't see it.

Maybe PCV problem, which is in the valve cover, or rings -do a compression and leakdown test.

Search google for burning oil causes.

[Efthreeoh]

Originally Posted by marvinstockman

If you were leaking that much oil, oil would be everywhere. Now your vcg may be leaking, but as I said, not that much oil.

Also, in normal driving, and if the cat is hot, it will burn the oil, and you won't see it.

Maybe PCV problem, which is in the valve cover, or rings -do a compression and leakdown test.

Search google for burning oil causes.

Just to clarify, the OP has a 2006 N52, so the CCV (PCV) oil separator is not in the valve cover, but rather is a separate device bolted to the underside of the intake manifold. The plastic valve cover N52 has the oil separator in the valve cover.

P-man, 400 miles per quart is a bit below BMW spec, which IIRC is 600 miles per liter, well maybe at the low-point spec considering a liter is about 2 oz. more than a quart. My engine has recently got down to about 1,800 miles per liter. Given the age and miles on my engine, I decided first to replace the CCV and see if oil consumption improves (I'd been wanting to replace it for about 2 years...). I've only driven the car twice since, so I can't report on an improvement for about a month. I did find my intake was dirty with wet sludge and fresh oil. I cleaned everything up and the engine runs a lot better now. My engine has remained constant in fuel consumption and power production, which keeps me from considering it is a ring issue.

Other owners have suggested the valve guide seals on the N52 go at high mileage and are the source of oil consumption. Or the oil rings. A compression test (dry then wet) is not a bad idea.

[porsche959]

Originally Posted by Efthreeoh

Just to clarify, the OP has a 2006 N52, so the CCV (PCV) oil separator is not in the valve cover, but rather is a separate device bolted to the underside of the intake manifold. The plastic valve cover N52 has the oil separator in the valve cover.

P-man, 400 miles per quart is a bit below BMW spec, which IIRC is 600 miles per liter, well maybe at the low-point spec considering a liter is about 2 oz. more than a quart. My engine has recently got down to about 1,800 miles per liter. Given the age and miles on my engine, I decided first to replace the CCV and see if oil consumption improves (I'd been wanting to replace it for about 2 years...). I've only driven the car twice since, so I can't report on an improvement for about a month. I did find my intake was dirty with wet sludge and fresh oil. I cleaned everything up and the engine runs a lot better now. My engine has remained constant in fuel consumption and power production, which keeps me from considering it is a ring issue.

Other owners have suggested the valve guide seals on the N52 go at high mileage and are the source of oil consumption. Or the oil rings. A compression test (dry then wet) is not a bad idea.

Thanks. wow 600 miles per liter is pretty bad no? that means the some e90 drivers are adding 7 quarts between oil changes?

was debating replacing the CCV but at $100 not sure if its worth it. seen some threads that said it did not help.

[porsche959]

Originally Posted by marvinstockman

If you were leaking that much oil, oil would be everywhere. Now your vcg may be leaking, but as I said, not that much oil.

Also, in normal driving, and if the cat is hot, it will burn the oil, and you won't see it.

Maybe PCV problem, which is in the valve cover, or rings -do a compression and leakdown test.

Search google for burning oil causes.

Had the car sit for 2 week. There was probably 1/3 a quart of oil under the front of the car.

I am hoping this is a VCG leak but...

[Efthreeoh]

Originally Posted by porsche959

Thanks. wow 600 miles per liter is pretty bad no? that means the some e90 drivers are adding 7 quarts between oil changes?

was debating replacing the CCV but at $100 not sure if its worth it. seen some threads that said it did not help.

It more like $320 in parts and a pain in the ass to remove and replace. You have to replace all three hoses (at least 2 of them) and the separator. If you DIY it, trust me, remove the alternator too, it will make it far easier to reinstall the manifold.

[marvinstockman]

Put a pan under the engine compartment, capture and measure the oil.

Also, a leak that big shouldn't be hard to find. Clean the engine and underbody, add ultraviolet engine dye to the oil, check with a black light a few days later.

[fastboatster]

Check the pcv, it's most likely failed. In february, my car started to ask for a top up almost every week. Turned out, pcv valve went bad. N52 in working condition should not consume any oil.

[smallseafishie]

do you have a CEL? That should be a pretty bad leak for those sort of mileages so it should be pretty obvious. I'd suspect the CCV too.

[porsche959]

Originally Posted by smallseafishie

do you have a CEL? That should be a pretty bad leak for those sort of mileages so it should be pretty obvious. I'd suspect the CCV too.

no CEL. and no exhaust smoke really.

im guessing its a combo of VCG leak, Oil Pan Gasket leak and bad CCV.

[drawz]

If you leaked 1/3 qt at rest, then it's certainly not being burned and I don't think VCG or PCV issue would occur at rest either. Check the oil pan gasket and make the sure the drain plug is torqued properly (and hopefully had a new crush washer installed with the last oil change).