603 Oil Leak Thread
 

Soon I'd like to start a 300SDL revival thread with many pictures of the procedures that I do, but that will have to wait for now. Anyways, I started this thread so as to eliminate my many oil leaks. I've gone 2k miles since the last change and my level is still pretty much to the top, but oil leaks are my
biggest automotive pet peeve.

First, the rear main seal is leaking on my 300SDL, which I have noted by the dripping oil from the bottom of the bell housing. I did a search and saw a post in Hattie's tranny re-seal thread by GSXR, and he mentioned the flywheel lock tool and a special sleeve. If I were to pull the tranny back towards the rear or if I pulled it completely out of the car, will the seal be accessible? I ask because I know on some MB cars the crank has to be raised. Also, is it a radial seal just like the front main one?

Second, my front main seal is leaking. I've replaced this seal on my brother's 601 engine, so I gather the hub/balancer setup will be close enough that I can figure it out. However, how does one remove the fan clutch? The 603 uses a different set up there than the 603.

Third, is my oil pan. I'll get the procedure for this off the CD and will post if anyone is interested regarding this. I don't really need the procedure so much as the torque values and tightening sequence. Does the sequence matter very much and what should the bolts be tightened to?

Fourth, and I think my last group, my IP seems to be leaking oil from around the bottom. I'm going to go out and take some pics then post them here to see just what I should do.

Are there any more seals that could leak on these cars? :D

Thanks
David

Pics...

1=stop lever, never knew a lever could leak???
2=is that diesel on top of IP? It's not black like oil, and certainly doesn't belong there...
3=oil leak at the bottom of the IP? is there a gasket to replace for the bottom cover? Can it be done on the car?
4+5=oil on top of waterpump. What around there would put oil there?

Thanks
David

Can you pull the oil pan without to much trouble on these? Mine has a very slight weep coming from the upper edge, just enough to make the seam dirty.

I have no idea how to seal IP leaks, I would like to know also because my bottom cover is leaking.

Then their is a mystery leak by the turbo I havn't figured out yet.

I also have some sort of mystery leak by the turbo. I haven't looked too far into it, but I want to get my car to the point that I can park it in a driveway and not mark my spot.
Thanks
David

I know what you mean, my engine is pretty dry none of the leaks I have are bad enough to drip. But my trans, I can't wait for it to warm up I want to seal that thing up. Leaving 6in puddles everywhere gets old. :rolleyes:

I think the only things that are actually leaving any puddles, though not 6 inches, are my front and rear crank seals. Then again I also need to pull of my lower engine compartment cover to double check all that stuff.

Thanks
David

First, replace the valve cover seal and the oil filler cap, both leak by this time and will dribble oil off both ends of the engine.

Rear seals on the 603 almost never leak -- they are a circular seal and the flywheel has to come off to replace them, so the trany has to come out (or the entire engine, since that is easier sometimes).

The head gaskets can fail on these engines and cause leaks, too.

You have something unusual going on, these cars are not known for leaks -- both the 603's my brother and I own use little or no oil in 6000 miles.

The drip on the bottom of the IP is fixable only be pulling the IP, a major pain. fuel on top is leaking pressure valve holder 0-rings, replace them and the seal (follow the proper torque sequence).

Peter

Maybe I'm the only one who has ever had the head drain get loose and leak dripping off the bell housing (no one seems to know there is one because you cant see it without a mirror) but mine did leak.

Located on the back side of the head between the firewall, (you'll need a mirror) there is a dime sized hex oil plug screwed in with aluminum washer. They can, and do get loose and leak!

I have replaced both rear and front main seals. Easy to do with the engine out. Also, the IP has a large rubber O-ring between IP and block.

Also, the intake manifolds tend to leak black messy residue if not real tight, or flat. Use a straight edge to check intake manifold flushness, more often they are not perfect (need to mill flat) and the gaskets dont always compensate. Residue runs down the side of the block and then gets blown back on everything (if you dont have a body pan) and can look like motor oil. BB

Peter, I replaced the oil cap soon after I got the car. Mine was naturally leaking but now is not. I read here that the IP bottom plate gasket can be done with the IP still on the car; I'll look into this possibity next time the car is on the hoist.(maybe sometime this week).

Busy, Could you be any more specific as to the location of this plug that you speak of? There is a washer on there that I should probably replace or does the whole plug come loose? From looking briefly at the car, there's not a lot of room so I guess I'll have to get a mirror to look for that one.

One more thing Peter, How do I get the engine fan/clutch off? I didn't see any obvious bolts holding it on like on my brother's 601. I want to do the front main, I figured I'd use the starter and a breaker bar to get the main bolt loose on the crank then use an impact with full air pressure to tighten it. My indie mech said an impact wrench would be adequate. To actually put the seal in it can just be tapped in like the wheel seals, I don't need the "special" installer? I can go to Autozone and borrow the hub puller so that's not a problem.

Also, my valve cover gasket doesn't seem to really be leaking but I want to take it off anyway to check for chain stretch. And what have you done to time your IP, take it to someone else with the RIV tester or did you use the "pop" thingy.

Thanks
David

P.S.
As I said, my car's oil lever hasn't dropped at all in the past 2k miles, the leaks are just annoying.

Thanks
David

Sorry for all the questions Peter, but Hattie mentioned something about some springs that should be replaced when doing the delivery valve seals? Do you know anything about these?

Also, I am now running Mobil 1 Truck and SUV oil, I switched 2k miles ago and don't intent to replace the filter for another 5k, which means 7k intervals. Without messing with oil analasys, am I alright doing as I am now? The car doesn't have an oil cooler so it only took 8 qts. thus also less of the old oil mixing in. What do you think?

Thanks Again
David

Thats a loaded queston that no one can really answer. You should be ok is the best I can say. But getting the oil tested say at 3k then at 6k is a very good idea. For $30 a test you will know for sure exactly how long you can go. Also it will red flag any problems, it cought coolant burning off in Brian C's oil. :eek: I recomend getting the oil tested on any engine if you want to go longer then 5k miles.

Also gsxr I think was saying that the bottom cover can be taken off the IP while it is on the engine. I think it can, it is the only thing leaking on my engine.

PM gsxr he really knows his stuff, or Sixto but I havn't seen Sixto around lately.

Their is a big bolt in the center of the fan that has to come out. Slide the plastic guard back and stick an 8mm allen wrench in the head of the bolt. Kind of a pain but I after you do it a few times it is simple.

I traced one of my oil leaks to a loose clamp on the air intake to the turbo....I guess I have more than my share of blow by. Anyway I tightened the clamp and no more oil leaking down on the water pump area and on a cooler line.

Dave, slide a mirror between the firewall and backside of the head. It's a tight fit but there should be at least 3/4" clearance. The plug should be on the drivers side of the head. You will see a slot for a hex wrench, can't remember what size but probably 4mm to 6mm. The plug has an aluminum crush washer. There should be just enough room to fit an alan hex wrench on and tighten. As mentioned, I did find mine loose and before tightening, I was loosing a quart a week. It's worth a check.......Don't know if anyone mentioned, but you will also need to remove the radiator first to get to the hex bolt to get the fan clutch off.

Good Luck............... :cool: BB

The radiator has to be removed to get the fan clutch off! That is absolutely rediculous! That means I would have to mess with trans lines and coolant lines. How do you guys remove the fan shroud so as to get to the bolt? Or do you just somehow maneuver a hex wrench in there and take them out together?

Thanks
David

Their are two little metal clips that hold the top of the fan guard in pop them out, lift it up a bit to get the tabs on the bottom of the guard out and slide it back over the fan. Plenty of room.

I have had my fan clutch out probably about a dozen times, thats how it comes out the radiator does not need to be moved.

Remember the W124's engine compartment is different then the W126's some of the procedures will be different because their is less space in the W124's bay. For example the oil filter canister is different, the radiator is also not the same.