Quote:
Originally Posted by adostrom
I did this job on my 2009 335i xDrive sedan last week. I found the tutorial very helpful, but I also found some items missing from both the tutorial and the Bentley manual. I'll add the caveat that I don't know if these will apply to any other years or models than my '09 N54.
First, people have been discussing replacing/not replacing the valve cover bolts. I talked to the dealer and they do not suggest routine replacement. The bolts on my valve cover are NOT aluminum, they're steel (put a magnet on one, and you'll see), even though they sort of look like aluminum bolts.
After following the Bentley manual I could not get the cover to come out. I found that loosening the fuel rail was required, and to get to the bolts holding the fuel rail I had to remove the air cleaner box (what BMW calls the "intake muffler"). This was beneficial in another way -- if provided additional slack in the cables which clip to the side of the box, which eliminated the need to disconnect any electrical connections. Thus, I also did not disconnect the battery.
My recommendation would be to remove the cabin air filter housing, the engine cover, and then the air filter box. At that point I stuffed the intakes with shop towels and gave the engine a good cleaning with some degreaser, which made checking for leaks after completion of the job a lot easier. Similarly, cleaning all the cavities on the top of head, once the valve cover was removed, will help me know if I have a leak in the future.
I had a lot of trouble with the new gasket falling out of the cover when re-installing, even after cleaning the groove carefully. I was going to use Permatex "High Tack" to hold it in place, but all I had was a spray can, so instead I carefully brushed a thin layer of Permatex "Aviation Form-a-Gasket" into the groove, which held the gasket in place nicely.
After torquing the valve cover to the spec I reassembled the engine enough (coils and injector/coil wiring) to get it running and then I ran it until it got up to operating temp. I let it cool (while reassembling as much as I could) and then re-torqued all the bolts. By running it with the cover and air cleaner out I had a much better chance of spotting any leaks, too.
[To be honest, I felt that the spec'd torque felt really loose (maybe the spec is for aluminum bolts) so I did some research on the torque specs for M6 bolts, and ended up torquing everything to 95 in.lb., which "felt" about right. I can't recommend anyone do anything other than what's in the book, but I've been doing this a lot of years, and decided to go with my gut on this one.]
The Bentley manual says to replace the bolts holding the strut brace, but none of the dealers in the Boston area had them in stock, so unless yours are better, plan ahead. I re-installed the old bolts while waiting for new ones to arrive.
With six new coils I ended up spending under $400 for the whole job. Like many jobs, doing it the first time took me a lot longer than it should; for example I spent at least an hour trying to finagle the valve cover out, once I decided to take out the air cleaner and loosen the fuel rail it was done in five minutes...
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Can you tell me what e torx size the strut brace bolt on the firewall is?