Help with oil leak on m110 engine 84 280SL
 

Hello all,

This is my 1st post.

I bought a 1984 280SL over 20 years ago. It has been a most excellent car. I have put almost 225k miles on it and have had virtually zero problems just the regular maintenance.

I took this car on a long trip recently and the rear wheel bearing/hub went out so I had that replaced at a MB dealer in MN. Got me back to CO and all was well. The other day I went out and noticed a big puddle of oil underneath the car in the front. Checked the oil and was very low, barely on the stick so I added some and it got me home. I put the car up on jackstands to see where exactly it is leaking. It was leaking hard and dripping pretty much steady. But one thing I noticed was if it is just idling then there is no problem - or it seems. It appears that when I turn the steering wheel it then leaks oil - engine oil and not PS fluid. I know in the past I had a slow power steering fluid leak but not all that bad. But now this is leaking engine oil. Was wondering if someone could explain how this could be happening.

Thank you!

Ricky

I would have to guess either a front crank seal, or a cracked head-to-sump oil-return line. Either could be leaking oil onto the front crossmember and in turn falling onto the P/S actuator, then falling to the ground when you turn the wheel, moving the actuator.

Okay, I will check that out. I have it up on jackstands now so tomorrow or the next day I will get all the oil cleaned off it and take a better look.

I am seriously considering restoring this car. It is in excellent shape and has never been wrecked. No rust as I live in CO. Like I said I am extremely pleased with it. If it is just the line from the head to the oil sump I will most likely just fix that and keep driving for awhile. But if it is the front main seal I will most likely have the engine pulled and have a valve job done and have the transmission checked out at the same time. Then while it is out I might replace all the rubber bushings and motor mounts. I am extremely happy with this engine and having talked to many MB entusiasts they all speak very high of the M110.

Thanks again for your help. I will let you know what I find - should be a couple of days.

Ricky

M110s leak and use oil, if the head hasn't been off at this point I'd probably go ahead and jerk the motor since you like the car. They rev high on the freeway.

Hello all,

This is what I have found. The car is currently up on car ramps and jack stands - all 4 wheels. I start the car and after a few minutes the oil was dripping in a steady stream out. It appears to be dripping down from just behind the power steering pump. I didn't see any leak from the main seal. There is like a round cap maybe about 3" ? with two bolts maybe about 14mm in size. The oil is coming down from the top of that. I guess it could be coming out the top of this cap and running down the cap or else above it - it is really hard to see. Does this make sense to anybody? Is this the area where the oil return goes in? I am just curious as to what exactly it could possibly be as it is pretty difficult to see from the top.

I had the top end done at about 150k and it still ran fine. I go 3k miles before changing oil and never have to add any although it is down. But if at all possible I would just as soon fix this and keep driving it. That is if this doesn't require pulling the engine.

Thanks to all for your input.

Ricky

The cap you are referring to is on the block. I'm not sure what it's for. The oil-return line connects to the upper oil pan about 5" behind the cap. It's a black plastic tube about 1 1/2" in diameter. But I'm more concerned about your car up on jack stands and ramps at the same time. Those ramps are only designed to hold 1 end of the car only, with the opposite end on the ground. Be careful!

Thanks EZRider,

As per your recommendation I will lower the backend and take the rear down from jackstands. Then the front only will be raised up on the ramps.

I didn't know what that cap is either. I guess I could just try to see if it will snug down some as maybe the bolts loosed. I don't want to take it off as I don't know. But the oil is coming out from either on the top of the cap that bolts into the block or someplace above it. I was just hoping to get a better idea of possibilities. I have both the MB 110 service manual set as well as the MB 107 chassis manual set. But I could not see in the engine manual this cap.

I might have to try to get a better look to see exactly where it is coming out. I will also double check the oil line but I think that is okay.

Okay, I have found it.

I found where this is leaking. On the power steering pump bracket there are a few bolts that hold it to the block. One bolt in the middle of the bracket was loose and the very top bolt which bolts the top of the bracket to to the block was completely missing. The bolt looks like it would normally be about 2" long and 3/16" in diameter or smaller. The oil can be seen coming out of this hole in the power steering bracket that the bolt normally goes in on the very top of the bracket. I guess I would not have expected that this hole would go completely through the block where oil could come though the hole if the bolt is not in. But at least at this point that is what it looks to be.

Does anybody, by chance, know the specs of this bolt? It is the bolt on the very top of the power steering bracket.

Also, on a different vein. Does anybody know where I can purchase a parts breakdown with the part numbers of this engine - 110.990 as well as the 107 chassis. I have both complete service manual sets but they don't give the part numbers.

Thanks for all your help!

Ricky