BMW N52 6 Cylinder Engine Tappet Noise
Q My 2007 X3 has intermittent pushrod lifter noise on the initial start up until the engine reaches full operating temperature. The frequency can vary from once every two to three months to sometimes twice a month. This all started two weeks after I purchased the vehicle new. The dealer told me that the noise should go away after the break in period. At 8,919 miles I brought the vehicle in for what they explained was a bleed down procedure per a service bulletin. The noise returned intermittently and at 20,152 miles I brought it in again. They could not reproduce the noise however they did change the oil and it seemed to work for about 6 months and then it returned intermittently again. When the frequency increased at 37,907 miles I scheduled another appointment and they replaced all of the pushrod lifters. Two weeks later the noise returned. Using a stethoscope I have determined it is the number one cylinder however I can’t distinguish if it is the intake or the exhaust. It seems to me that there is some type of oil delivery problem however the dealer will not take any action until they can reproduce the noise. The vehicle now has 39,000 miles and has been at the dealer for over a week as they try to reproduce the noise. Your thoughts?
A The 6-cylinder engine in your 2007 X3 3.0si is from the N52 engine family (most 6-cylinders from 2007 to current, and some 2006). This engine is well known for the hydraulic tappet (lifter) noise. This has been typically attributed to too much oil bleed off in the cylinder head oil galleries that supply the pressurized oil to the tappets.
BMW has the following three “fixes”, which are only performed if the customer complains enough … and in the right way:
1) Perform tappet bleed-down procedure (typically does not provide a permanent fix).
2) Replace the tappets with an improved unit that bleeds down slower (sometimes cures the issue).
3) Replace the complete cylinder head with an improved unit that does not bleed oil pressure and flow as quickly and keeps more oil at the tappets when the engine is not running. This is of course the most expensive fix, but it is the final fix.
We could not locate a service or repair bulletin on this, but most people must really hound the dealer and request a review by the regional BMW rep. in order to achieve the final cylinder head fix. Don’t give up …. BMW is obviously well aware of this issue since they have redesigned the head and the tappets. They are just not so interested in replacing cylinder heads under warranty.
As for the dealer, in your case, refusing to go further unless they can reproduce the noise, try taking a video of it with the noise happening … show it to the regional rep.