Is it best to drop front subframe to change oil pan gasket

[Robert K]

Well, I'm going to have to bite the bullet and replace my oil pan gasket. It has squeezed out a bit near the front and the leak is getting worse. I think my car would be leakfree if I could fix this. I've looked over a few recent posts but wanted to ask a few questions. First, is it NOT possible to change the gasket by simply raising the engine up? I believe Bentley makes it sound like the pan comes right out if you just raise the engine as much as possible. But I also think I remember one or more persons saying it just isn't possible. I also really do not want to drop the oil pump unless it's absolutely necessary. I believe I remember George saying that he ended up dropping the whole front crossmember to get the pan off. I'm just trying to determine exactly what I'm going to have to do before diving into this one. I hate to have to do it, but sometimes, "a man's gotta do what a man's gotta do." Wasn't that in a movie or something???

Any info would be greatly appreciated.

Grace and peace,

Robert K
very leaky 1991 535i

[winfred]

i remove the fan or shroud and then jack the engine up and put a 4" wood block under each motor mount, after you get all of the bolts out of the pan and it's sitting on the crossmember unbolt the oil pump and drop it into the pan, now you can remove the pan. make sure you locktight the nut on the oil pump sprocket when reinstalling, i had one come off a couple years ago, it sucks doing the job twice

[George M]

either way Robert it is not a fun job. Believe Winfred's approach is easiest...I dropped my engine X-mbr to do it. Easiest...is a bit of a misleading term however. The pan and oil pump are much easier to finesse on and off with with the X-mbr removed. Removing the X-mbr is more work of course because you have to disconnect the lower control arms, disconnect the steering box and hang it via stiff wire off the intake manifold bracket and also the engine mounts come down with X-mbr so nothing to prop the engine up from...have to restrain the engine from up top with either of cherry picker or chain fall.
I suggest if you go in...change your oil pump while you are at it. Many reports of dimished oil pressure as the M-30 gets into the 150K mile range due to increased pump clearances.
I suggest you not try to do the job in one outing. Give yourself a generous time window to help your mood during the "operation".
George

[George M]

Winfred...you say you had an oil pump sprocket bolt come off. Presume you got an oil pressure warning light....did it make a mess below?...would think the chain would catch and maybe snap. Not a bad idea to use loctite 242 on all the oil pump bolts.
George

[winfred]

no mess, the damn nut just fell off and the sprocket was hanging from the chain


Winfred...you say you had an oil pump sprocket bolt come off. Presume you got an oil pressure warning light....did it make a mess below?...would think the chain would catch and maybe snap. Not a bad idea to use loctite 242 on all the oil pump bolts.
George

[Hector]

and as George says it is a PITA job. I couldn't jack the engine high enough to insert wooden blocks. It just wouldn't go high enough. With the engine jacked as high a possible on the ac compressor and power steering points, I wound up doing what George suggested a while back, dropping the x-member but only dropped the left side while the other side was still bolted. The bolts were loosen such that a few threads were holding the x-member from dropping completely. I had plenty of room to remove the pan. Now just need to put everything back together.

[TC535i]

Robert, just a thought... You might want to just get under the car and tighten up the oil pan bolts without dropping anything. On mine, they just got a bit loose in parts, tightened them up a little and it stopped leaking.

Worth a shot, anyhow...

[Hector]

if your car has very high mileage, I'm willing to bet that the oil pan gasket is pretty much toast by now. If you tighten the bolts you might wind up cracking the already brittle gasket and the leak could get worse. Depending on the mileage, I'd change the gasket and be done with it. If you are like me, I don't like to see leaks of any kind springing from under the car whatsoever!!

[TC535i]

if your car has very high mileage, I'm willing to bet that the oil pan gasket is pretty much toast by now. If you tighten the bolts you might wind up cracking the already brittle gasket and the leak could get worse. Depending on the mileage, I'd change the gasket and be done with it. If you are like me, I don't like to see leaks of any kind springing from under the car whatsoever!!

Between this thing and my '86 325es, I don't think of them as leaks, so much as "marking its territory". ;)

[Hector]

my car on the other hand has other ways to mark it's territory--not by piss-drops all over the driveway :o)


Between this thing and my '86 325es, I don't think of them as leaks, so much as "marking its territory". ;)

[George M]

Hector...a couple of tips on your X-mbr bolts. The X-mbr for postional tolerances is piloted as you probably know...their are a couple of hollow pins in the X-mbr that fit tightly in sized/sleeved holes in the car's sub frame. If you lowered your X-mbr down lower than than these sleeve/dowel pins...exercise due care when bolting/shoring the X-mbr back up to the stub frame...you will likely loose alignment and it will take some
"coaxing" to get the X-mbr back on the car properly...much easier with a cherry picker keeping the engine weight off the X-mbr. Also, I strongly suggest replacing all (6) carriage bolts...3 on each side 4 medium length and 2 long...that secures the X-mbr to the stub frame. These bolts get a lot of exposure and can snap upon re-torquing...ask me how I know...I broke one off and had to remove the X-mbr a second time when I changed my suspension set up the second time. Order replacement bolts from BMA as a precaution...good insurance anyway long term as these bolts due take a lot of road assault. Adhere to Bentley's values for torques as these bolts will break upon re-torque if over torqued...torque values are not high as they are long...two in particular are long and narrow and can not sustain high torque without fracture.
HTH,
George

[Hector]

I need to pay more attention to these pins because I don't remember seeing them but then again I didn't have the x-mbr dropped all the way down. Regarding the bolts, when I loosen them up the first time; water, rust deposits... came out of the x-mbr/subframe bolts holes. Caught me by surprise! The threads on each bolt were rusty (I mean really rusty) and full of deposits/crud. I will replace all bolts but what worries me is that the threads in the subframe oughta be rusty as well. I've given them it a good dose of WD-40 but this is only a temporary fix, and I wonder when the threads will be completely eaten away. I don't know if these can be re-tapped to a somewhat larger DIA or if I can use helicoils.

[George M]

I wouldn't worry about the sub frame weld nuts. Give 'em a good shot of light oil by removing a bolt at a time and replacing with fresh bolts. The pilot sleeve on each side of the X-mbr is about 1 inch long as I recall. If you dropped your X-mbr more than that then likely the sleeve is out on that one side and you need to be careful to line it back up. Normally it takes a bit of persuasion to get the dowel pins to find the sub frame...again easier without the weight of the engine on the X-mbr. The X-mbr is sensitive to getting bound up if you don't bring it up the same amount on each side.
George

[Hector]

I think the sleeves are aligned. I've removed these bolts 3 times already and have been able to screw them back in with no difficulty. Lucky so far, I guess.


I wouldn't worry about the sub frame weld nuts. Give 'em a good shot of light oil by removing a bolt at a time and replacing with fresh bolts. The pilot sleeve on each side of the X-mbr is about 1 inch long as I recall. If you dropped your X-mbr more than that then likely the sleeve is out on that one side and you need to be careful to line it back up. Normally it takes a bit of persuasion to get the dowel pins to find the sub frame...again easier without the weight of the engine on the X-mbr. The X-mbr is sensitive to getting bound up if you don't bring it up the same amount on each side.
George

[gale]

I took the crossmember off my e28 to send out to have it straightened (wife high-centered the car over a median:(). It wasn't that hard a job, just a bit involved. For some reason, the e32 looks more complicated than I remember the e28 was. I anticipate removing the crossmember on my e32 this summer to do the pan gasket. If you notice the plastic caps on the tops of the "chassis" rails in the engine compartment, they pry off easily & I periodically squirt a 1/2 oz. of motor oil in all of them. I wrung of one of them in the e28 when tightening it & they were all rusty. The broken one came out easily with an ez-out & I replaced it with a new bolt. I suppose it wouldn't be a bad idea to put a heli-coil in it.

http://www.nmia.com/~dgnrg/chassis-p1.jpg

http://www.nmia.com/~dgnrg/chassis-p2.jpg

I plan on supporting the engine from above with a liftframe/strongback made out of a 4x4 with 2x4's on the ends with a slit cut in them to register in the fender ridges & snatching onto the lifting eye near the thermostat housing:

http://www.nmia.com/~dgnrg/liftframe.jpg

[Hector]

little lube on the treads...

I almost rented a cherry picker but didn't want to haul it from point A to B, didn't want to work in a hurry as I would've been charged on a daily basis for the tool, and didn't want to haul it from point B to A. The local rental place also charges for hauling this thing around had I decided go this route.

I got this technique down of lifting the engine from underneath the car... it's just a bit time-consuming but it can get a little crowded under the engine with wooden blocks, floor jacks...

Thanks for the visuals as well.