N52 extreme oil consumption

[gyurej]

Hi All,


My 2005 e60 523i 133k km consuming 1 litre of oil every 500kms. Yes that's a lot, has been consuming first 1L every 1k km very slowly degrading since 20k km.


Replaced CCV and connected hoses twice, head gasket, valve cover gasket, intake side valve seals no effect.
Dry and wet compression looks OK with cheap Chinese tool, no errors thrown, exhaust pipe gets black on the outside but no visible smoke except a occasional small puff of blueish smoke on startup after few hours sitting. More than usual white steam in cold weather, goes away when hot. No external leak except few drops of oil on bottom of gearbox probably from rear crank seal, but never anything on the floor.
There was nothing obvious when removing the head, except for two cylinders.


Cylinders 3 and 5 have plugs covered with dry black soot and are also wet in the inside, other plugs look good but thin black layer on the bottom metal ring, thin black dry deposit on the top of pistons but might be normal.


Unfortunately I didn't take the head to a shop when it was off as seeing the intake valves (pics) i concluded that the seals were the culprit. Exhaust valves were all covered with very thin black layer, except 3 and 5 with thicker cover, all dry, my spring compressor anyway didn't fit to replace exhaust seals.


I still suspect an issue with either the CCV system or intake valves. I removed intake manifold 3 times, each time there is oil at the rubber seal to the engine and I would think only the valve rods would be black instead of the whole intake port if it was valve seals. Intake manifold had 1 spoon oil in it but has not been cleaned for 20k km, no obvious oil pooling inside the manifuld since last 2k km. I once run the engine with CCV hose disconnected from intake manifold and the hose was throwing out a lot of oil, which again might be normal without intake vacuum?


Some pics below of intake ports and oil around manifold screws and seals. Any idea?

https://ibb.co/cgL5jf
https://ibb.co/bYrpAL
https://ibb.co/cTP9AL
https://ibb.co/mjYfH0
https://ibb.co/ewNwqL
https://ibb.co/eT5hVL

[02Pilot]

What is the crankcase vacuum at hot idle?

Black soot is likely fuel, not oil. Possibly you have leaky injectors that are washing fuel into the oil. How does the oil smell?

[bmwdirtracer]

+1, check the crankcase vacuum. From O2 Pilot's epic oil consumption thread, here's how to make a manometer at home:
https://www.bimmerforums.com/forum/s...lacement/page8

In your pictures, I note that none of the intake passages actually look wet or oily. The oil which I see seems to all be EXTERNAL, especially on top of the head gasket. Since you've gone so far as to replace the head gasket, I understand that you've been thorough.....but are you absolutely sure you don't have an external oil leak, from the oil filter housing gasket? I replace these every week, including the heat exchanger gasket. They are HUGELY common leak spots on this engine.

Look on the front of the engine, under the oil filter housing....then behind the housing, since you've got SO much oil at the head gasket seam. (I am not suggesting the head gasket is the culprit, just that this is where the oil collects)

Anyway, make a manometer, fill it with colored water, drill out a spare oil fill cap (the one on the valve cover), and test your crankcase vacuum. Vacuum should be 3 to 6 inches of WATER. (Oops, sorry: 7.5 cm to 15 cm of water.)

[gyurej]

Thank you both, I could and probably should check for crankcase vacuum. I have not done it yet because suction at the oil cap wasn't very high. There is a bit of vacuum but very easy to open the cap.

I did start by replacing oil cooler and filter housing gaskets as they were indeed leaking a bit, no help. I should be very easy to notice an external leak of this severity.

The oil you see on the head gasket are drops of oil rolling down from each of the intake ports when I removed the manifold. The ports and the manifold tubes are only slightly moist. If I disconnect the hose from the CCV to the manifold, that one is very oily in the inside. I didn't find a way to look if any oil is pooling on the bottom of the manifold, but today I removed the manifold after having driven 600km and there were again few drops of oil at the seal of each intake port.

Would so much oil disappear with leaky injectors and wouldn't petrol keep the valve rods clean in the affected cylinders? Without the dipstick it is difficult but through the oil cap I do not feel any fuel smell. Nor did I notice anything strange in oil consistency when I replaced oil after the head gasket change in May.

[bmwdirtracer]

It just seems to me that 1 litre every 500 km should make for a whole lot of smoke from the exhaust, and a definitive trail of oil to the combustion chambers, if it's being burned. And, as you point out, that much oil being leaked should also leave a trail. Since we're not seeing either trail, I'd have to recommend more testing, and crankcase vacuum would be the first test. Second test would likely be a leak-down test, to see if you've got a piston-ring issue.

[Leinhobmw]

Bump!im having the exact symptoms as op. Changed following gaskets: oil pan, oil filter housing, oil cooler, rear main seal, vcg. Also changed pcv hose running from vc to intake manifold. No visible smoke from exhaust.
Things is It apparently consumes oil only on long trips (highway speeds).. aboit 1liter every 500km.
I have preovuosly changed valve cover from eBay but have normal vacuum númbers apparently.
Should i check valve seals?
Op did you resolve the issue?
What else should i try? I rrslly like this car but its getting under my skin !!

[Knkaa]

Did you ever find a solution? Having the same issue here....

Bump!im having the exact symptoms as op. Changed following gaskets: oil pan, oil filter housing, oil cooler, rear main seal, vcg. Also changed pcv hose running from vc to intake manifold. No visible smoke from exhaust.
Things is It apparently consumes oil only on long trips (highway speeds).. aboit 1liter every 500km.
I have preovuosly changed valve cover from eBay but have normal vacuum númbers apparently.
Should i check valve seals?
Op did you resolve the issue?
What else should i try? I rrslly like this car but its getting under my skin !!

[BuildAndDrive]

Sorry to hear you are having the same issues as I was. I did EVERYTHING to try and stop the oil consumption on the car but ended up rebuilding the engine in my garage. I made some DIY Youtube videos about it if you're interested. https://youtu.be/-tJ7utqWZQY

[Knkaa]

Wow, amazing video thread!