[AlecNguyen330i]

Hi all, I recently purchased my new to me 2006 330i One-Owner with 71K miles. Since then I have put four or so thousand miles on it and it has been burning oil like crazy. I'm afraid it may be rings and/or valve guides or seals. It is a MAJOR problem. The car doesn't smoke on startup or under every acceleration. The only time it smokes it when I accelerate quickly like using the button on the pedal or under load like brake/gas to spin the wheels. I've done a little test to see if it could be the PCV(remove oil cap for pressure) and there was none. One thing I will note that leads me to believe oil on spark plugs, is that start ups often take a second or two longer to crank. Other than this it really shows no actual symptoms of rings like lots of smoke and or loss of power the car feels strong and healthy. I just hope some of you'll could help me remedy this before to long. It is my only car and between work I don't have the time to be tearing it down to check plugs etc. I've used to treatments of Liqui-Moly motor oil saver to regenerate any "seals" but I know that it wouldn't help rings if that's the problem.

[F31cruisin]

There are a number of points that leak. Valve cover gasket, oil filter housing gasket, and oil pan gasket. You sure none are leaking?

[AlecNguyen330i]

Originally Posted by E90cruisin

There are a number of points that leak. Valve cover gasket, oil filter housing gasket, and oil pan gasket. You sure none are leaking?

Yes, almost positive none are leaking, I've checked under the car in the mornings. I will also say if I go on a very spirited drive the car will lose 1/2 a quart of oil. But like I said I'm just very concerned about the smoking and it being rings or something. I've actually added 16 quarts over 5,000 miles...
So average 312.xx miles per quart. I need to figure this out I know just adding oil isn't really the best at almost $30 for a 5qt jug of Castrol Edge but I'm afraid it'll just get worse. Thought about running 5w-40 instead of 30 but have read the engines not designed for it

[desertman123]

You won't see the oil pan gasket leak under the car without taking off the belly pan.

[hassmaschine]

I would be looking at the CCV system.

[tlow98]

Originally Posted by AlecNguyen330i

Yes, almost positive none are leaking, I've checked under the car in the mornings. I will also say if I go on a very spirited drive the car will lose 1/2 a quart of oil. But like I said I'm just very concerned about the smoking and it being rings or something. I've actually added 16 quarts over 5,000 miles...
So average 312.xx miles per quart. I need to figure this out I know just adding oil isn't really the best at almost $30 for a 5qt jug of Castrol Edge but I'm afraid it'll just get worse. Thought about running 5w-40 instead of 30 but have read the engines not designed for it

Where did you read that about the 5w-40? Many people run 0w-40 or 5w-40 with no issues.

Given the high vacum conditions of your issue I second what hassmaschine says about the CCV system.

[rjahl]

Originally Posted by tlow98

Where did you read that about the 5w-40? Many people run 0w-40 or 5w-40 with no issues.

Given the high vacum conditions of your issue I second what hassmaschine says about the CCV system.

Unless abused, the N52 is a really tough motor. I had 205,000 miles on my 2007 and would only loose about 1/2 to 3/4 quart between oil changes at 10,000 miles. Some of that was leaks at the rear main seal and pan gasket both original.

Keep looking into your Crankcase Ventilation system.

[Noir]

Going off what was said above, if your car is "drinking" the oil and there is no oil stains in your driveway, 10/10 the crankcase ventilator valve is your culprit. Happened for me. I usually have to top off a quart if I am constantly getting on the car at 3k intervals. But when the new clutch was installed and I drove "normally" never burned a drop.

[PhaseP]

Originally Posted by rjahl

Keep looking into you Crankcase Ventilation system.

Plus one on the CCV. 1 qt per 500 miles, if it is a leak will eventually fill up the under belly cover and start to drip.

Your return tube on the CCV could have been plugged inside, if so oil coming from crank case won't be able to return back to the oil pan, and only other place it would go is through intake manifold back to engine and get burned up.

The test to see if there is too much vacuum on the crankcase by opening the oil fill cap is a diagnosis for one failure mode of the CCV. The valve may be working which would not cause too much vacuum, but return line could be clogged. If you could take out the intake manifold you would fine good amount of oil in it if this is happening.

[arhoads335i]

while the car is running take the oil fill cap, see how much blow by it has.

[BimmerNugget]

Originally Posted by E90cruisin

There are a number of points that leak. Valve cover gasket, oil filter housing gasket, and oil pan gasket. You sure none are leaking?

Don't forget the RMS. Those tend to leak too.

[BimmerNugget]

Originally Posted by rjahl

Unless abused, the N52 is a really tough motor. I had 205,000 miles on my 2007 and would only loose about 1/2 to 3/4 quart between oil changes at 10,000 miles. Some of that was leaks at the rear main seal and pan gasket both original.

Keep looking into your Crankcase Ventilation system.

Efthreeoh has 335,000+ on his 06 325i These N51/N52 motors sure are tough!

[phsullivan]

I will add to the chorus of people calling for the CCV. I also have an e90 330, with about 105k on it. Last fall it all of the sudden started sucking down oil. It had some leaks previously that were all replaced (oil filter housing, valve cover and oil pan). In about 800 miles after the valve cover and oil pan gaskets (I found broken aluminum "head bolts" while doing the valve cover) were replaced it nearly emptied itself of oil. When I replaced the CCV system the inside of the intake manifold was covered in oil so I knew I had found the culprit.

The CCV job is pretty easy, the biggest part of the job felt like getting all of the shrouds and covers etc out of the way. I've done a couple of thousand of miles since then without measurable loss of oil.