alexanderfoti

Hi all

I have a fairly large oil leak on my 221. Its making a mess of my driveway!

I cleaned up the underside of the car, then I drive 200 miles and its covered again. Seems to be worse on the left side of the engine

(passenger side in the UK, drivers side across the pond).

Thinking it may be the turbo oil drain, but that thing in the picture doesn't look like it to me?




Left turbo wastegate actuator:

alexanderfoti

OK so its the oil cooler thermostat that is bolted to the side of the block.



If I clean the oil off and start the engine, oil appears between the pressed metal plate, and the body of the housing (where the droplet is in the last picture of the car).

I think its going to be obvious that its probably the gasket to the block that is leaking, and no easy way of changing other than removing the engine?

Welwynnick

Not sure if it helps, but with those impossible access jobs, I would always support the engine and lower the front subframe. You get great access then.

Nick

alexanderfoti

Thanks Nick.

I assume to do this, I would have to disconnect all the suspension and cooling pipes etc?

So far I have managed to remove the left engine mount and 3 of the 4 bolts on the left mount bracket. Just waiting on a set of torx spanners to get the last one out. I can then hopefully gain access to that side piece that is leaking.

Welwynnick

No. The wires and pipes are untouched, except for the PAS return pipe, and the wires to the PAS valve and the ABC pressure control valve.
Well done! Is the last one the left front upper bolt by any chance? A singularly difficult bolt! One ratchet click at a time.
It sounds like you're close as you are, good luck.

Nick

alexanderfoti

Ah yes I see! I thought you meant dropping the engine with the Front subframe for some reason!

Yes that's the one! Front upper bolt. Am hoping that an offset torx spanner will fit. I will then remove the plate and hope that the oil leak is actually from there and that there is an o ring there.

If it's from the ring between the block and the oil cooler then the turbo will have to come off. I assume I can get access to do that by dropping the subframe as you recommend?

Welwynnick

Yes, that's how I removed my turbos a couple of years ago, but lets hope it doesn't come to that.

alexanderfoti

Fingers crossed. It does look likes it's leaking between the plate. It's an odd place for a leak....

MooksM275

Just FYI, that gasket cannot be changed without removing the front timing cover. Has to do with bolt location (inside and underneath the bracket that holds abc pump. (like 100%). I bought the gasket when I was doing other work and ended up not being able to change as I didn't prepare to remove timing cover.


Best,

alexanderfoti

Thanks mooks.

Its actually leaking on the side plate that contains the three torx bolts.

I managed to get it off yesterday, had to remove the mount, mount bracket and the wastegate actuator as one of the 3 torx bolts rounded off. Having removed it, its clear that somebody else has been there before and replaced the o ring with one that is too small!



I am thinking of replacing the hard to get at e Torx bolt with a stud and nut so that its easier to get on...

alexanderfoti

All back together now. The stud in place of the troublesome E torx bolt worked well. Getting the nut started was tricky but a bit of grease and a screwdriver helped with that.

Welwynnick

Congratulations. That must have been a tricky job.

Nick

alexanderfoti

Thanks, I hope to never do it again.

alexanderfoti

Having fixed that leak, its become clear the there is ALSO a leak at the o ring for the oil cooler pipe (that can be seen in the picture with the oil drop on it).

Its a much slower leak, so I am not so worried about it, just wonder if I can remove that line to replace the O ring. I can get to one bolt holding it on. Not sure on the other.

Kebowers47

Oil Leak Hell! For all you folks experiencing numerous oil leaks on these V-12 engines, that is NOT NORMAL unless the engine has been run very hot and with too long oil changes.
I STRONGLY RECOMMEND "BLUE DEVIL Hydraulic leak stop. " This stuff WORKS WELL at reconditioning oil seals and 'rubber' gaskets---IF they are not cracked.

This is the ONLY such 'magic mouse milk' I ever suggest one use, and that is based on my personal experience with it in my 2001 S-600 ABC system, fixing the control valves leak-down issue.

Sam87

Hi,

I know this is an old thread but I wanted to ask, has anyone removed the oil level sensor that is above the engine sump?
My car has a leak from the level sensor but I can't see any screws and I doubt it's just been pressed in. I think the O ring has failed.
I'm just thinking if it has been screwed in from inside and in order to take the sensor off I will need to remove the oil sump? [ Hopefully I won't have to remove the engine sump ]
Any advise would be much appreciated

Kebowers47

The oil pan must be removed to Rans R the level sensor. An alternative is to thoroughly clean around the sensor (drop the oil level first) with 'brake cleaner' and then apply a bead of silicon (RTV) sealer to seal the sensor to the oil pan. Be sure and allow the RTV to dry and cure completely before restoring the oil level and operating the car. A little work can save you several hundred dollars over the Dealer price for fixing the leak.

JohnLane

Oil level sensor is an easy task. Yes; drop the sump pan, unplug lead to level sensor, unbolt it from inside, clean all surfaces and reassemble.

I would DIY without hesitation.

Sam87

Thank you for your reply!
I bought an O ring from Mercedes and now I will remove the oil pan. I just didn't know if the sensor was screwed from inside. Now it makes sense
Thanks again

Sam87

Thank you!
I'll get it done myself and report back how I get on

JohnLane

I have a new oil level sensor for a 275 if you need one.