BMW Oil Consumption

bmw
oil
x5

#1

We have a 2005 X-5 with 80,000 miles.

We have planned to keep the vehicle long term. We have changed oil every 3000-5000 miles.

During the past 5000 miles we needed to add 3 quarts. (the prior two oil change cycles we added a quart each).

There is no oil on the garage floor and no smoke out the exhaust.

Any thoughts/suggestions?


#2

If you’re sure there are no leaks (sometimes a leak never hits the floor; it’s blown back and off the car) then the oil has to be burned. There is no smoke because the converters are catching it.
This means valve seals and/piston ring problem. There is no test for valve seals but a leakdown test may reveal a problem with rings.

It’s possible to have piston rings sludge up due to caked or coked oil. The oil control ring (or wiper) is most prone to this problem and this is usually caused by any overheating in the past or not changing the oil regularly enough due to driving habits and conditions. A lot of short hop/stop and go stuff is the main cause.

If you suspect a ring problem try adding something like SeaFoam or Berryman B-12 to the engine oil and see what happens. Piston ring replacement means expensive bad news.


#3

Thanks for the guidance.
One thought that has been suggested is that the oil seperator is defective— does this make sense to you?


#4

If you are using the recommended German Castrol oil, ring sticking or coking is not the problem…Check the PCV system from end to end…

What type and weight of oil do you use?


#5

You just may have a leak and the skid plate keeps it off the floor. I changed two 3.0 6cyl heads for material porosity that caused oil loss (in 2002)

The oil seperator is a BMW version of a PCV valve, sometimes called a “cyclone valve” or “crankcase vent valve” when they go bad the engine “moos” like a cow, idle speed can be affected. Not a nice job on either the 6 or 8 (at the back of the intake)They do go bad.


#6

The BMW dealer has done all of the oil changes; I believe that they use
Mobil 1–synthetic; 5w30; when I have added oil I have added Mobil 1, 5w30.
The car is used for many short runs (less than 5 miles) so we have changed oil more frequently than recommended, approximately between 3,000 and 5,000 miles.


#7

I’ll defer to oldschool on the oil separator since BMWs do not fall under my area of detailed knowledge.

To be honest, on a car that sees driving conditions like this the oil should be changed about every 3k miles or 3/4 months; whichever comes first.
Five mile or less hops is the most severe service that can be put on an engine.

I would definitely make sure there are no leaks by physically inspecting the bottom of the car. What can often happen is that speed on the roadway will blow oil back and coat the bottom of the car to some extent. What residual oil there is will drip off before the car goes into the garage. I’ve seen some cars with oil smears all the way back to the rear axle.


#8

There is something wrong and the others have offered several good suggestions.

It won’t likely help with this problem, but in general, I have not had good luck with Mobile 1 in my BMWs. I know all the independent tests show that it lubricates the best, but my cars leak it and consume it. I have switched back to Castrol Synthetic in my newer two BMWs and Castrol GTX in my older BMWs.


#9

Don’t most car companies consider 1 quart every 1000 miles normal consumption?


#10

3 quarts in 5,000 miles is high, but not outside the usually acceptable.

BTW, in modern cars, you don’t need to change the oil any more often than indicated in the owner’s manual, really. Taken to the extreme, it can actually cause increased wear (of course you need really really sensitive test to measure it.)