M60 oil pump experience

[FWinNH]

I had previously read multiple accounts of people finding that the 3 fasteners that mount the oil pump (1 bolt and 2 nuts actually) have a habit of coming loose on the M60 engines. I knew that my 1994 540i has had the nikasil short block replaced with Alusil (based on the block part number). I therefore sort of expected that these oil pump fasteners would have been retorqued and lock-tited during reassembly and therefore would be OK on mine. But I also figured it was easy enough to drop the lower oil pan and take a gander at the next oil change just to be safe. That next oil change was last weekend...

Well, I'm very glad that I did check because the bolt was lying in the bottom of the pan and both of the nuts were considerably looser than the torque spec. I reinstalled the bolt and snugged everything down to spec using red loctite, so hopefully it won't come loose later.

A couple of things I found during this job:

One is that the drive chain to the pump was a bit loose. The spec is 10mm of slack and I measured 15mm. The adjustment is supposed to be the hex things between the pump and the block, but I could not budge them with an open end wrench but did not want to go with cranking on them. Has anyone here ever done this adjustment? Maybe I should just not take chances and put a new chain on there since it has stretched so much.

The second thing was that the steel oil pan had been significantly deformed at each of the bolt holes. It seems that somebody cranked the bolts down (ostensibly to eliminate an oil leak?) and the old style cork gasket caused the pan to be bent up at each bolt. I was able to bend the pan back into shape pretty well by supporting the pan with 2x4 blocks and hammering/punching the dents down with a 1/2" x 1/2" x 6" block of pine. This was required due to the redesign of the gasket. It is now a steel plate with a neoprene lip on the inside edge. In the deformed condition the pan would not have even hit the lip and would have leaked like a sieve. Good thing too because a new pan looks like it runs a couple hundred bucks.

[Evan]

I had the same experience when I bought my 540 but I didn't think it meant much because my car has the original block. I'm glad you checked and avoided a huge mess

[tim s]

even though we retorqued them all last year.
i plan on checking them once a year.
tim s.

[salansky]

Same experience on my '95 with a alusil swap. I had my indy drop it a couple of years back due to the rumors and he found 2 bolts.
I should probably recheck them again since I have basically had to redo everything else that clown did.
-jack

[FWinNH]

Same experience on my '95 with a alusil swap. I had my indy drop it a couple of years back due to the rumors and he found 2 bolts.
I should probably recheck them again since I have basically had to redo everything else that clown did.
-jack

Did you guys use locktite when you retorqued them? JUst wondering if I need to add this to my Inspection 1/2 checklists.