N52B25 Oil Consumption
Discussion
I brought my 2007, E92 325i (2.5) automatic approved used in 2012. It had 43,000 miles on it.
Having been shocked by having the carbon build up in my Audi S3 removed I wanted a port injection engine... I brought my first BMW.
After driving 2800 miles (little traffic as I start work early) it requested a litre of oil. My driving style is moderate and very rarely spirited. The roads are 30/50mph. A large chunk of that being 50 on the North Circular. Journey to work being around 40 minutes. On most weekends it has always seen a motorway drive as we visit family often - sometimes up to 120 miles away.
Where was I? After adding 1 litre it saw me through 1600 miles before requesting another litre. I read up online and came across various articles suggesting more regular oil changes. I started to change oil every 6,000 miles. This meant I would add a litre after 1500-1700 miles. I even tried changing oil at 3,000 mile intervals and once saw 2400 miles before a litre top up was required.
Things progressively got worse. An oil consumption test was commenced through BMW. The car went through a litre in just over 760 miles.
The dealership stated that this was on the cusp of tolerance. The warranty claim was denied. I was advised to investigate out of pocket.
So I did... Different tests. A compression test came up good. Little difference in compression between cyclinders. Sounded promising. Wet compression was also good. There were no leaks. The mileage was 59,000. Valve cover gasket and oil filter housing spotless. Smoke tested too and no issues.
At one point it seemed like there was excess white smoke from the exhaust but this came and went. It was literally a plume at idle but never returned. I have had friends drive behind me with a dash cam and no excessive exhaust gases have been identified under various driving conditions.
The mileage is now 75,000 miles. I continue to get through a litre of oil between oil changes. A litre being requested anywhere from 760-1700 miles. There is no telling so I carry oil and check the electronic dip stick regularly.
The dealership I went to. Mentioning no names... Turned out to be one of the most honest service/sales guy I knew. He told me that investigating it would become expensive and that BMW would not carry out any warranty work on my 8 year old car. Although it has been serviced at this dealership since new. The only independent garages it saw were for the tests. He suggested I try 10w40 oil but I don't think he knew what he was saying. The manual states 0w30 and it has had nothing but that since new. He hinted that I might be accused of over filling when topping it up.
Other than the requirement for oil it is a beautiful car - especially since ditching the run flat tyres. I'm at a loss what the problem could be. The oil separator is not a stand alone serviceable part on mine which is a shame - I don't know if it is that for sure but clutching at straws.
Further research points toward design. The discussions put it down to the inland oil rings being thin and allowing oil to push past them. I think I could be on to something there as the oil is used mostly under load i.e. Car full of passengers on a motorway run always sees the dipstick drop a notch or even two. The same journey alone rarely sees movement on the dipstick. I'm not a mechanic though my knowledge runs out there.
The service/sales guy I spoke with did give me a brilliant suggestion but he doubts very much that it would work. His idea was simple. Start an oil consumption test. Drive around with bags of cement and the likes in the boot... Burn the oil under the 750 miles tolerance and come back in. I'm thinking of giving it a try...
So that is my story and I'm putting it out there for others to reference. If anyone has any advice or information please feel free to add.
Thanks for reading and hope you did not go cross eyed.
Having been shocked by having the carbon build up in my Audi S3 removed I wanted a port injection engine... I brought my first BMW.
After driving 2800 miles (little traffic as I start work early) it requested a litre of oil. My driving style is moderate and very rarely spirited. The roads are 30/50mph. A large chunk of that being 50 on the North Circular. Journey to work being around 40 minutes. On most weekends it has always seen a motorway drive as we visit family often - sometimes up to 120 miles away.
Where was I? After adding 1 litre it saw me through 1600 miles before requesting another litre. I read up online and came across various articles suggesting more regular oil changes. I started to change oil every 6,000 miles. This meant I would add a litre after 1500-1700 miles. I even tried changing oil at 3,000 mile intervals and once saw 2400 miles before a litre top up was required.
Things progressively got worse. An oil consumption test was commenced through BMW. The car went through a litre in just over 760 miles.
The dealership stated that this was on the cusp of tolerance. The warranty claim was denied. I was advised to investigate out of pocket.
So I did... Different tests. A compression test came up good. Little difference in compression between cyclinders. Sounded promising. Wet compression was also good. There were no leaks. The mileage was 59,000. Valve cover gasket and oil filter housing spotless. Smoke tested too and no issues.
At one point it seemed like there was excess white smoke from the exhaust but this came and went. It was literally a plume at idle but never returned. I have had friends drive behind me with a dash cam and no excessive exhaust gases have been identified under various driving conditions.
The mileage is now 75,000 miles. I continue to get through a litre of oil between oil changes. A litre being requested anywhere from 760-1700 miles. There is no telling so I carry oil and check the electronic dip stick regularly.
The dealership I went to. Mentioning no names... Turned out to be one of the most honest service/sales guy I knew. He told me that investigating it would become expensive and that BMW would not carry out any warranty work on my 8 year old car. Although it has been serviced at this dealership since new. The only independent garages it saw were for the tests. He suggested I try 10w40 oil but I don't think he knew what he was saying. The manual states 0w30 and it has had nothing but that since new. He hinted that I might be accused of over filling when topping it up.
Other than the requirement for oil it is a beautiful car - especially since ditching the run flat tyres. I'm at a loss what the problem could be. The oil separator is not a stand alone serviceable part on mine which is a shame - I don't know if it is that for sure but clutching at straws.
Further research points toward design. The discussions put it down to the inland oil rings being thin and allowing oil to push past them. I think I could be on to something there as the oil is used mostly under load i.e. Car full of passengers on a motorway run always sees the dipstick drop a notch or even two. The same journey alone rarely sees movement on the dipstick. I'm not a mechanic though my knowledge runs out there.
The service/sales guy I spoke with did give me a brilliant suggestion but he doubts very much that it would work. His idea was simple. Start an oil consumption test. Drive around with bags of cement and the likes in the boot... Burn the oil under the 750 miles tolerance and come back in. I'm thinking of giving it a try...
So that is my story and I'm putting it out there for others to reference. If anyone has any advice or information please feel free to add.
Thanks for reading and hope you did not go cross eyed.
With these feet said:
Sadly they all like a drink.... mine might be the earlier derivative - '06 325i,but still the same basic design. Im getting around 3000 miles from full to top-up (still waiting for the alert) though I must admit that when I filled it it was not requesting oil, just I wanted to see for myself. The level indicator seems bloody unreliable, went from full,doing 2000 miles, to 1 mark remaining in 300 miles and has sat there currently travelling a further 250. It also takes a bloody age to register the added oil so overfilling is fairly easily done.
Have you any leaks, has the breather system been checked or replaced? Most common is the crankcase breather chucks oil (vapour) into the intake and burns it off.
This is not a stand alone serviceable part on the N52N B25. Mine is a January 2007. Similar to the 2006 like yours. From mid to late 2007 the direct injection variant was introduced.Have you any leaks, has the breather system been checked or replaced? Most common is the crankcase breather chucks oil (vapour) into the intake and burns it off.
Edited by With these feet on Sunday 27th March 09:02
I replaced my oil condition sensor at 65k miles as it was giving false readings. There was no fault code for it. I had the oil drained out and measured - lucky for me I had not overfilled.
Gassing Station | BMW General | Top of Page | What's New | My Stuff