Minor oil leak from bottom of bell housing...any suggestions.

[Doobit]

Hi guys

I noticed a small oil leak from the bottom of the bell housing on my 325i manual. Pretty sure it’s coming from higher up and not the housing itself. It’s not a massive leak however whilst I have time I’d like to fix it. Not sure if it’s related but selecting first gear is a major ballache but I assumed this was worn parts in the shifter rather than transmission oil related. Any suggestions?
Thanks

[paultv]

Could it be a spot of clutch fluid...a failing slave cylinder could leak and cause lousy gear engagment...dab yer finger on the fluid...oil is smooth between thumb and forefinger whilst hydraulic fluid has a strange catchy feel on the skin....quite unpleasant.

If its oil it could come from crank output shaft seal or gearbox input seal...and then of course the rear half moon rubber seals on the back of the head can allow oil to run along the bell housing seams and end up at the bottom looking like a leak from inside.

Paul

[steve_k]

as paul says above check the slave cylinder, also, which side is it coming from? drivers or passengers?

as well as being the rear main seal it could also be leaking from the back of the sump as the gasket could've given up.

[ChrisHC]

If clutch fluid is leaking out, air might be getting in; try pumping the clutch a couple of times and see if that makes it easier to select first gear.

[Brianmoooore]

The first thing to do is check the level in the clutch fluid reservoir. If the level is low, then it's clutch fluid dripping, and related to your gear selecting problem. If the level is OK, then the selection problem is caused by oil contamination sticking the clutch plate to the flywheel.
You should easily be able to tell oil from clutch fluid by taste. Clutch/brake fluid is doesn't taste at all nice.

[Doobit]

Thanks guys, really helpful advice. much appreciated.

Having checked it’s definitely oil, feels tastes like oil and clutch fluid level is ok.

Oil is on the drivers side of the bell housing, the passenger side is completely clean.

I can see oil above at the rear of the engine, I can see oil around the sump and above the sump. also there’s oil coating the transmission tunnel 8 inches back from the bell housing but I think this is a separate leak.

Any suggestions on what to do next? Before I start draining and disconnecting stuff.
Brian, I had assumed the dodgy selection was gear linkage, better news if it’s a leak as the linkage job looks like a right bastard.!

[Brianmoooore]

Gear linkage is easily removed on an E30 to refurb it, especially if you have a ramp to get underneath the car. Not quite so much fun jacking the car and lying under it, especially in winter, but still easy. There's one clip that has a knack to removing, but easy enough once you know how, and you don't need to remove it to replace most joints.
For the oil leak, the first thing to do is to thoroughly clean everything up with degreaser/steam cleaner/pressure washer, then put the car back into use, watching carefully for the oil to reappear and where it comes from.

[Doobit]

Thanks Brian
I decided to check out you thoughts that oil contamination on the flywheel/clutch plate was causing the first gear selection issue.

I took off the bell housing reinforcement plate (4 hex and 5 torx bolts) and the oil pan gasket is knackered at the right hand side rear with quite a lot of oil dripping and some on the flywheel from what I can see, I assume it’s also on the clutch plate.

I’ll sort the oil pan and gasket, if it leave it at that do you think the issue will resolve or do I need to get at the clutch and flywheel to clean it.
Thanks

[Brianmoooore]

Very common place for a leak. I have a theory that the other bolts for the sump have probably been tightened a few times over the years, but these at the back, being hidden under the plate, have just slowly worked themselves loose.
I'd certainly leave the clutch for a while and see if things improve. You may have a failing clutch cylinder as well, of course, so I'd open the bleed valve while you're under the car, get someone to push the clutch pedal 3/4 down, and tighten the nipple while they hold it there.
If this improves things for a while, start saving for new slave and master cylinders.

[Doobit]

Thanks Brian, I may have damaged the sump myself when lowered the sump down onto my toolbox last year.

How easy is it to remove the oil pan without removing the engine? I’ve read on here that it required jacking the engine mounting bearings on wood, removing steering rack etc. I might just send it to a garage and get the whole lot done.

[Brianmoooore]

It's not the most fun job in the world, but it's do-able on a DIY basis. Basically, block of wood between jack and bottom of sump, release engine mounts, jack the engine as high as possible, checking that nothing is trapped or crushed as you go. Insert wooden blocks of appropriate size in place of engine mounts, to keep the engine up, remove jack, then undo all the sump bolts. Reach in over the edge of the sump to release the oil pump, then remove sump. I don't remember having to remove the steering rack.

[Doobit]

Thanks Brian