1985 300CD valve gasket leak. - PeachParts Mercedes-Benz Forum

Lincoln · #1 03-07-2010, 05:07 PM

Ok...I'm starting a new thread with all info (hopefully) about my car so I hope the mods will let it run because I really need some help.

The valve gasket on my 300CD was leaking so I decided to buy a brand new one and get rid of the problem.

After my first attempt I ended up with a bigger leak than before. I decided to re do the job and pay attention to torque etc, that people kindly suggested on my first thread.

Well...last Friday I gave it another try . I took off everything around the valve cover so I could clean it well and sit the cover and the gasket in just one movement.

After I did it, I went with a flash light an checked meticulously the gasket to make sure it was sitting properly, started the engine and to my frustration the oil started to come out again.

I tried different torques and even different torques on each bolt bot nothing seems to be working.

One thing that I noticed is that the oil comes from one side only the side of the injectors never from the side of the air filter.

If I cant get some help pretty soon I will have to bring it to a mecanic and pray that the guy knows what he is doing.

Hope somebody can help!!

Lincoln · #2 03-07-2010, 05:39 PM

Oh yeah...forgot to say that as a last resource I'm thinking about applying silicone around it.

Any thoughts?

GLIDEHM · #3 03-07-2010, 05:51 PM

It is possible that your valve cover is warped. You should be able check this with a really flat surface, and look for places that you can see light through. If you do decide to place a small amount of gasket sealer, I would recommend Permatex Indian Head Gasket Sealer. Oil will not break it down like silicone. I've been using it on all of my tranny pans for years and have yet to experience a leak yet. I have only used it on valve cover gaskets one time, and that was on a small block chevy, but they still havent leaked since then, so I dont know why it wouldnt work on the Benz. Just a thought. I'm sure others will chime in and provide some other posiible explanations.

GLIDEHM

toomany MBZ · #4 03-07-2010, 05:51 PM

Do you know if the cover is not warped?

Lincoln · #5 03-07-2010, 06:27 PM

Thats good info guys!! By the way I would like to thank Jimmy because he is really trying to help me.

Indeed I can't tell for sure if the cover itself is not warped I guess I have to see.

In case it is. can somebody tell me how to apply the sealer? Should I take the cover and gasket out and apply in such a way that the gasket will "seat" on it or just seal around without parts removal? it seems to me that the oil will not let it stick...oh boy sorry about the newbie questions!!!

toomany MBZ · #6 03-07-2010, 10:47 PM

I'm not sure sealer will help if the cover is warped.
I use a coating of grease on the cover, then mount the gasket.

rrgrassi · #7 03-07-2010, 11:47 PM

Also, if you remove the cover again, clean the cover and the gasket really well. Also make sure the gasket is seated on the cover properly, IE the cover sits in the groove fully. Along where the injectors are, the gasket can look like it's seated fully, but is not. Use a counter top to see if everything sits flush.

Been there. The PO of my car used a sealant, and it still leaked. Plus I had the pleasure of scraping off all the sealant. IMHO, sealant is best for the cork type gaskets.

vstech · #8 03-07-2010, 11:51 PM

I seem to remember the cover can be damaged if over-torqued. the area the nuts fit onto, can get damaged too.
don't forget that another thing that can make the motor look like the vc is leaking is fuel return lines leaking fuel all over the head...

Lincoln · #9 03-08-2010, 01:54 PM

Thanks for the tips guys.

I'm sure it is sitting properly rrgrassi, I re did it just to make sure of this particular point.

I will probably buy another gasket and try my luck before going to the mechanic. I bought the 12 $ one at the discount autoparts and they have one for 17 $ maybe the more expensive one will work.

Thanks again guys!!

rrgrassi · #10 03-08-2010, 02:25 PM

Order the one from Phil on this sight. Since I have done that, no more issues, and no use of any type sealant was needed.

Biodiesel300TD · #11 03-08-2010, 04:36 PM

You might make sure you don't have washers sitting on the threaded posts that the valve cover goes over. That would prevent you from ever getting the valve cover on fully.

Lincoln · #12 03-08-2010, 05:28 PM

The whole thing was installed in as clean as possible biodiesel300TD.

This time I even took the cruise control out to seat the cover/gasket in one clean movement.

I inspected the gasket and it looks perfect no damages.

I'm thinking more and more about the valve cover being warped. Mercedes engineers only designed this cover with 4 screws what I believe is a flaw, any less than perfect valve cover will leak since pressure around the gasket can be uneven pretty easy.

Anyways I'm gonna try the glue suggested above and if nothing works gonna call my mechanic and hope he can solve the problem.

barry123400 · #13 03-08-2010, 09:11 PM

You should check the valve pan for warpage and eliminate it before going to an independant. You can also clean any oil barrier present off with laquer thinner. It dries very fast and will make the metal recieve any sealer properly.

I would not give up at this stage. You can prevail.

gatorblue92 · #14 03-08-2010, 09:43 PM

Quote:

Originally Posted by rrgrassi

Order the one from Phil on this sight. Since I have done that, no more issues, and no use of any type sealant was needed.

x2... i got the cheap autozoo brand and it leaked as soon as i put it on... got the one from fastlane and problem solved... in fact i am now oil leak free

Lincoln · #15 03-09-2010, 05:50 AM

Ok...I'm sold!

I'm gonna order a gasket from Phill and see how it goes. The one I got from discount auto parts says "made in Germany" but I guess it will not kill me to try something else.

I will also check for any warpage as soon as the valve cover is out.

I will keep you guys posted....again...thanks !!