craft1

I have a simple question that I need an good answer for.

I recently changed my moms friends oil on her CL500 and at that time noticed the oil pan leaking. SHe said go ahead and change the oil and she will get the oil pan fixed later. Well she woke up this morning and had a decent sized oil spot on the floor, so I came over and removed the underbody panels and saw the leak had gotten worse. So she said to go ahead and fix it.

Now here is my question. I have the oil pan off, had to stop since it is dark now, but when I reseal this oil pan, is there a specific way I need to apply the sealant?

I talked to my friend who is a tech at mercedes and he said you basically apply a 2MM bead around the oil pan and around the bolt holes then apply the oil pan. He also said what he does is once he applies the sealant around the pan, he rubs it all around so to make a good seal. But I have never heard of doing that. I have heard just to apply a bead and then install the pan. Now I have done other oil pans and have heard different ways to do it. But I want to know what way specifically mercedes says so the pan wont leak again.

Any techs for mercedes on here have any recommendations? Oh and I will be using the liquid gasket from mercedes.

D_TECH

I apply the bead, then wipe around the entire pan...insuring I've gone around the bolt holes and everything is even. I dont know if you need to, but my teamleader taught me this way and I havent seen any of my pan reseals leak.

vettdvr

I know this is "understood". but both surfaces must be clean and not have an oil film. If the surface is not clean you will have difficulty making good seal. Keep us advised on how it works out.. take pics also if possible. Jim

craft1

now there is my next question.

Since I dont have a machine to clean the pan or any air tools, what is the best way to completely clean the mating surfaces of the block and pan? And is there anything I can do to clean the inside of the pan itself.

Also what do the guys in the shop use to smooth up the pan surface?

Alex1

smooth up the surface? you shouldn't need to.
Cleaning use 2+2 gum cutter or degreaser spray, then grab a blow gun and blow it dry(cover your eyes), i guess you can use some compressed air for that too.

clkcarol

As far as what kind of sealant to use, us Corvette guys swear by "The Right Stuff", available at parts stores, i.e., Pep Boys, etc.....
Just follow the other prep. pointers, especially the CLEAN part, and apply the bead as stated. Allow 24 hours to set up.

MBTech21

OK- here is the right way and it works, if you use the black MB sealant- nothing better for any sealing job , in my experience. MB has said for years now- 'do not smear'- only the bead has to be applied in a certain pattern- (some bolt holes are open to oil, others are not)- the pattern is available on WIS or in the intro books. You could actually figure it out yourself by looking at the bolt holes in the pan and/or block (or go around every hole if you wanted). Clean is important- dry is more so. Most guys use a diegrinder with a 3M scotchbrite pad to clean it.
After the bead is laid, install it cleanly (ie: no rubbing around to line up the holes). No set time is required.

craft1

what do the techs right now use to clean up the sealing surfaces?

MBTech21

I thought I said that- a diegrinder with a 3M scothbrite pad. If you don't have one- scotchbrite is available in a sheet and do it by hand. After that, spray with brake cleaner and wipe dry.