Slow oil leak, about 1 Quart every 1200 miles. Help please.
 

Hey guys,

My 2007 4.8i with 105,065 is leaking about 1 Quart every 1200 miles. I'm looking at the warranty paperwork done and it looks like BMW already replaced

1. upper timing cover gasket (both sides)
2. oil cooler thermostat and gasket
3. valve cover gasket (both sides)

This work was done at 74,000 miles.

Any ideas what else could cause this slow oil leak? Any help is appreciated.

What brand, type & grade of engine oil are you using? You have the N62 engine, which has specific issues to attend to. N62B48B is a later version, which is in your E70. Are you certain it's a leak as opposed to consumption? CCV (leak) is a known issue as are valve stem seals (consumption).

I'm using Mobil 1 0W-40 European formula. I've own the car for 5 years, and it have never consume this much oil until now. That's why I'm assuming it's a leak. Would the X5 consume more oil as the car age?

Maybe I should take the splash shield off and see if there's any oil in the driveway?

Not sure about the X5, but many of the other BMW's can leak a lot of oil and the lower engine cover keeps the oil from spotting the driveway.

I am also no fan of the Mobil 0W40 oil either. Not sure if you have been running this for a long time. But this stuff does not go in my cars. Have heard many have oil consumption problems with this blend of oil.

Not sure if a bad CCV or lack of proper crankcase vacuum could also cause this. I know this is the case with the I6 engines, not sure with the V8.

Ok, thanks. I'm gonna take the lower engine cover off this weekend and see if there's any oil spotting on the driveway.

I've been changing my oil with Mobil 0W40 for 5 years. Haven't had any issues. What oil and grade do you recommend?

So if you have been using the Mobil 1 for 5 years, this is probably not the issue. I tend to use the Castrol 5W40 that is BMW LL-01 approved.

You probably will not need to wait and see if there is any oil on the driveway, it will likely be on the top of the lower engine cover if is has been leaking as well all over the bottom of the engine. Hopefully you have an oil cooler, because the interface to the engine is much easier to remove to replace the gasket then removing the alternator bracket.

Good luck.

Some of the more common leak locations are the oil cooler adapter housing if you have an oil cooler or the alternator bracket where it mounts to the engine if you do not have an oil cooler. Just look inside the lower drivers side grille and see if it

here's what my engine cover looks like. I don't see any oil spots. Do you?

I do have an oil cooler, but it was replaced along with the gasket under warranty in 2013 about 25,000 miles ago.

Not as clean as mine, but not looking too bad.

Possible CCV problem or valve seals and burning oil now?

Not sure about the 4.8l, but I know the I6 have low tension oil rings and will burn more oil when the crankcase vacuum is poor.

Do you have an OBDII scan tool that supports Live/Realtime data? If so, monitor warn idle fuel trims and see what the values are. Not sure it is good idea on the 4.8l, but crack the oil fill cap and keep the cap over the hole so oil it not thrown out and see what happens to the Fuel Trims when the oil fill cap is cracked.

I have a 4.8l but have not looked carefully at the CCV system to understand how and if this can be a contributor to oil consumption when it ages/fails.

How are you verifying the oil level? Oil level indicator? Dip stick? My 2008 4.8l has a dipstick still, however, I know some did not.

change your CCV, that's the go to with oil consumption. i think your car has an updated design with alternate hoses for moving the CCV making it an easier job than the older motors.

if you're burning out the tail pipe you can try an engine cleaner like BG109 but dont drive the car with a cleaner in it. just run the engine without high revs, drain, change filter, and refill.

I've been going by the oil level indicator that pops up on the LCD and the dash. I do have a dipstick, but did not check it. I'm gonna look into the CCV system.

I don't have OBDII scan tool that supports Live/Realtime data.