Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
Confidence Drainer
My Z4 was purchased one year ago with only 15k miles. The car is 100 percent stock… no mods. On a trip home at 70-80 mph, oil smoke began appearing in my rearview. Upon inspection, it appeared to be a cam cover oil leak. My Indy garage diagnosed a blown cam cover gasket and replaced the gasket and the cam cover. I now have 17k miles and all is well.
But I wonder: was the turbo pressure so high that my problem may reappear? Does it have a PCV to relieve pressure? How and when do I replace PCV? Should I install an oil catch can? Please help me find comfort with this. The repair expense was high and I have lost some confidence in the Z4’s reliability.
Thanks,
Steve Getz
Odd to hear about that kind of failure at such low mileage. However, the B58 does have a common failure of the crankcase valve that is incorporated into the valve cover. This particular item tends to fail around the 50-75k mark. Some of the newer B58 engines allow this part to be serviceable but some of them come with a new valve cover assembly. I am not sure on the production range of that item but I have performed repairs to both the crankcase diaphragm itself as well as a complete valve cover assembly.
The only advice I can offer right now is to continue to drive the car and see. What you experienced tends to happen later in the mileage of the engine but perhaps you had an odd one and it failed at the 15k mark? I can tell you the B58 has been a solid engine for the most part. I rarely performed any repair other than the one stated above and the heat management module leaking.
Transfer Case Worries
I just bought a 2019 X5 4.0i with 36k miles. Car has been well maintained and very well optioned. In reading about the 2019 G05, I see a lot about transfer case and transmission issues, and the need for extra maintenance.
Do you have any advice on this year in general or the drivetrain issues I mentioned?
Thanks in advance.
Dave Schempp
Charlotte, N.C.
The main piece of advice to be aware of is to stick to the OEM tire sizes designated by the label on the B-pillar. Transfer case failure is consistent with deviating from these exact tire sizes (wheels too) which causes the DSC/VTG control units to incorrectly operate the transfer case causing internal failure. This was very consistent with the previous generation X3/X4/X5/X6 platforms. I would also recommend to change the fluid in the transfer case at 30k mile intervals. As for the transmission issue, the only one I occasionally dealt with was a leaking rear output shaft seal.
Other than that, no real issue and no real extra maintenance. The B58 X5 is by far one of the best all-around BMWs (in my opinion) and if you inspect, service and repair the vehicle regularly you will be fine.
Lifetime Transmission Fluid?
I have a 2008 650i (E64) convertible with six-speed sport automatic transmission. My car has 33,500 miles. I like my cars to be maintained and up to date with the recommended maintenance as required. Car runs great, no leaks, and no issues. The car has the original transmission fluid.
I have asked several club members their opinion, if I should change the transmission fluid. Some say yes, others say no. I took my car to my local BMW dealer to check the fluid level for peace of mind. Fluid was on full and no fluid added. I asked the tech, if I should change the fluid. The answer was no, do not touch it. Quote “BMW uses lifetime fluid and is meant to never be changed including the differential, unless there are issues or something going on where a fluid change would be necessary.”
My question is, do I change the fluid or not, and what you would recommend? With only 33,500 miles, I would guess no, but the car is 17 years old.
Thank you,
Rick Baker
Sagamore Hills, Ohio
This is a tough one with the E64 chassis. Technically CBS data calls for transmission service at 100k miles. I have done a few in my day. But at the same time there was reluctance to change that fluid unless it was directed by BMWNA in a technical case. I recall reusing old fluid if I had to remove the mechatronics module (valve body) when there was an issue back when under warranty. Whether this was because it was expensive fluid or they wanted the friction material kept with the transmission it came out of, I do not know.
But with this chassis and your situation, I would lean towards if it has not broken do not fix it. But if you really want fresh fluid in there, I think the risk is low enough that replacing the original fluid will not affect transmission operation.
