pan removal on 230SL, cast AL

[Ron]

After running the poll on oil leaks, it looks like most of you have a dry car.  I guess this car is not like my old Healey, and it can be leak free, so I've decided to try to fix the rear main seal.  Mine is leaking after a PO rebuild with about 300 miles on the engine.  My questions are:

1.  Does this have a pan gasket?  (it looks like, no)

2.  Can you get the pan out by disconnecting the motor mounts at the motor arms, and lifting the motor (with an engine puller), while lifting the body off the sub frame (with jacks)?  (sub frame still connected)

I want to get the pan out so I can do a correct lower seal installation, as per Dr. Benz's instructions, with .040" on each side, as I'm assuming the PO incorrectly installed the seal with flush cuts on all 4 ends.

3.  Are all rope seals the same?  I still have the gasket set packing materials, so I know the name of the company that made it, but I normally would order the rope seal from M-B.

Thanks in advance for your ideas. 

Ron

[Shvegel]

When I did my engine the factory seal was a carbon fiber impregnated seal. Looked pretty good to me. I am not sure you can pull the pan without pulling the engine or dropping the sub-frame.

 Regardless stuffing the seal in around the crank might be a pain. I have seen tools for this for Fords that looked like a pair of Chinese hand cuff but I have never used one.

[Ron]

Thanks Shvegel.  I was referring to the pan gasket, in asking of the engine had one.  This gasket would be around the outside of the pan and block interface.

In reading the posts on the rear seal, my conclusion is one can only pull the pan and replace the lower part of the seal.  Both upper and lower are pinned so they will not slide out.  Therefore the crank must be pulled to get to the top seal.  I was hoping to pull the pan, and pull the lower seal part, cut a new one a bit longer, and reinstall the pan.  From the posts I've read, the seal, both halves, that is all 4 ends, must be about 0.020" above the surface before the pan and block are mated.  This will ensure the seal gets a crush fit.  I'm assuming my (presently "new") seal was installed by the PO with a flush fit.  If I pull the pan, and put in a new lower seal with 0.040" above the surface, then the crush fit could work and no leaks.

That was my plan.

Ron

[ja17]

Hello Ron,

Yes the upper half of the seal is pinned. Make sure the rope seal is pressed firmly into the aluminum pan slot  before installation of the pan. Otherwise when you tighten down the pan the seal will move further into the slot and be short again! The old manuals show a guy using a big hammer's wooden  handle doing a press and roll on the rope seal to make sure it is all the way in place. I grease up the rope seal and use the wooden handle of a hammer also.

On the other extreme, if the rope seal is left too long, it will pinch the crankshaft tightly making the engine hard to rotate, or may keep the pan from clamping down tightly to the block.  There is no gasket on the aluminum pan to block surface.   I avoid using silicone seal on these oil pans. Permatex #2 works best for me and seems closer to what was originally used by MB. Clean both surfaces and wipe with alcohol, use a light coating on both surfaces and on the ends where the rope seals are joining. Grease the crank surface of the rope seal and install the pan.  I would plan on removing the rear main bearing cap first and check the main bearing for problems while your in there.  When a rear main bearing fails it causes enough wobble at the crankshaft rear seal to cause a significant leak!

Anyway, am not sure how far you can get removing the pan without lowering the subframe a bit or lifting the engine.  Remove the front steel sub pan first and remove the oil pump, this will allow much more clearance to remove the large aluminum oil pan. The steel "sub pan" does have a gasket and it is unique to the W127 engines like yours. These "sub pan" gaskets are graphite coated on one side and most often part without damaging themselves. Sometimes just using Permatex with the old undamaged gasket and re-installing works fine. Probably not worth the risk if you are able to get the correct new gasket in time.


Keep us up to date!

[Ron]

Thanks for the input Joe. 

In looking at the documentation that came with the car, it has new rings and bearings, installed by a machine shop.  The head was redone then also.  So I'm thinking the upper half of the rope seal was put in correctly, last year. 

The PO told me he put on the pan and the head, so I'm thinking he did not do all that correctly.  I should have known to pull the pan before I put the engine in, after some clues on this "rebuild" showed up.  (valve timing was off, timing chain worn, tach drive seal missing, and other odds and ends.)

BTW, the car did stop blowing steam, so the head gasket is ok.  After 300 miles, it still has some blue smoke, and black if too rich.  But hopefully I can get the black smoke under control, and the rings will somehow set up.

Ron