Valve cover question - PeachParts Mercedes-Benz Forum

psaboic · #1 04-13-2014, 09:37 PM

Hello all,

Well, it seems like my valve cover gasket has not set right since the last time I adjusted the valves. I opened the hood today to find it leaking at the front corner just forward of the injection pump. Lots of oil splatters blown back onto the heater hoses and the oil filter cover, and firewall. and after about 2500 miles I have lost about a quart of oil.

Anyway, when I checked to see if the valve cover hold-down nuts had come loose, I found out that the forward stud on the drivers side (same side that is leaking) has stripped threads and will not torque down properly.

Now for the question.....has anyone had this particular problem and successfully fixed it? I know I have to replace the stud, but what is the best way to remove and replace it?. My best guess is that after removing the valve cover I could just clamp a set of vice grips on it and try to remove the stud by backing it out.

Also once I (hopefully) successfully replace the stud, what is the best way to seal the gasket? No sealant, or something along the lines of blue silicone....

Glenn

tangofox007 · #2 04-13-2014, 10:12 PM

My first strategy would involve a thread repair die. With the stud in place. And a new nut.

Stretch · #3 04-14-2014, 02:14 AM

You might have to go for a thread insert if the old threads can't be repaired (as mentioned in post#2)

Check the valve cover for straightness - flatness on the mating surface; then replace the gasket. A correctly fitting valve cover with a new gasket should not leak.

psaboic · #4 04-14-2014, 09:19 AM

Ok, I guess I should clarify a bit. The stud is starting to strip on the top threads where the nut goes to hold the valve cover down. It is nice and snug in the head. Might be the valve cover as I have had an issue with this particular leak area for the last 30,000 miles off and on

Dan Stokes · #5 04-14-2014, 09:59 AM

I use my table saw as a surface plate. It's an older Craftsman and has a ground cast iron table (don't trust the ones made from stamped sheet metal). You can gauge flatness by sliding a feeler gauge between the bottom of the cover and the table. Not sure what's "too much" but I'd flatten whatever you find and shoot for as close to zero as possible.

To replace the stud - if you don't have access to a stud driver (they have them at Sears) you can try the double nut trick. Run a nut down on the stud followed by another nut. Tighten the nuts against each other as tightly as you can. Turn the bottom nut (closest to the head) to the left and the stud generally will come out. I always reinstall studs with the double nut technique (tighten it with the top nut) as a stud driver will leave a mark on the stud and could cause a stress riser.

Dan

psaboic · #6 04-16-2014, 11:58 PM

Ok, the 300D decided it was not going to wait any longer. Today I popped the hood to check the oil while at the fuel station, and my oh my....... Turn out that the nut on the stud with the stripped threads decided to part ways with the rest of the car. End result was that corner of the valve cover was no longer held down. What a frickkin mess! I figure I lost almost a quart of oil and most of it is coating the drivers side of the engine and the firewall.

Got it home, pulled the valve cover off, and since there were no threads left on the stud to try the two-nut method I had to resort to vice grips to back the stud out. Finally got it out, and tomorrow I am off to the hardware store to find a matching thread stud, or bolt and nut.

Guess I will check the valves again as long as I have the valve cover off (did them about 2800 miles ago though so they are probably ok). Then after I get it all back together I get to clean the engine bay.......Yay!

Anyone else replaced one of these studs and stoped a leak successfully? If so and you have any tips, send them along.....I'm POSITIVELY sick and tired of having a leaky valve cover gasket.

ROLLGUY · #7 04-17-2014, 11:28 AM

A hardware store will not have the proper stud. The stud has a shoulder on it so the cover can maintain the proper distance from the head. The only stud that will work is one from another engine, or one from the dealer. Do yourself a favor, and find someone (or a wrecking yard) that has one from a spare engine, or get one from the dealer.

toomany MBZ · #8 04-17-2014, 11:34 AM

Seems to be three different studs.

ROLLGUY · #9 04-17-2014, 11:40 AM

Quote:

Originally Posted by toomany MBZ

Seems to be three different studs.

Yes, two of the four are the same (manifold side) and one of the other two has a shorter shoulder (bracket underneath makes up the difference).

psaboic · #10 04-18-2014, 08:54 AM

So does anyone have an online source for one of these studs? The nearest dealership to me is over 150 miles away. The stud I need is the forward one on the drivers side of the motor.

Thanks,

Glenn

tangofox007 · #11 04-18-2014, 09:25 AM

Quote:

Originally Posted by psaboic

So does anyone have an online source for one of these studs?

A search for something along the lines of "Mercedes parts" should reveal plenty of options. It did for me. (Pelican Parts appears to be one of those options.)

http://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2014.cgi?SUPERCAT_FLAG=Y&make=MBZ&Context_make=MBZ&please_wait=N&LastVisited_input=&Previous_Section=&forumid=&threadid=&command=DWsearch&description=6160160170&I1.x=10&I1.y=7

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2014.cgi?SUPERCAT_FLAG=Y&make=MBZ&Context_make=&please_wait=N&LastVisited_input=&Previous_Section=&forumid=&threadid=&make=MBZ&description_side=6160160170+&GoSearchSideFlag=T&command=DWsearch&command=DWsearch&REFINE=Y&FORUM_REFER=&SUPERCAT_FLAG=Y&Previous_Section=&LastVisited_input=&make=MBZ&description=6160160070+&x=52&y=15

charmalu · #12 04-18-2014, 10:17 AM

Quote:

Originally Posted by tangofox007

A search for something along the lines of "Mercedes parts" should reveal plenty of options. It did for me. (Pelican Parts appears to be one of those options.)

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

This is interesting......

Warning: this part may not fit your 1985 Mercedes-Benz 300D Sedan.

What is so different with the 85 VC? I have an 85 since 1997, 84 Sd and a 1/2 doz engines. Don`t se ea nickles worth of difference.

Some things on the 85 Fed and especially the Kali 85 are different, but the VC Studs?

Now why did this go to red?

Charlie

ROLLGUY · #13 04-18-2014, 10:35 AM

That stud should be the same for all 61X engines (616,617).

tangofox007 · #14 04-18-2014, 10:53 AM

Quote:

Originally Posted by charmalu

This is interesting......

Warning: this part may not fit your 1985 Mercedes-Benz 300D Sedan.

What is so different with the 85 VC? I have an 85 since 1997, 84 Sd and a 1/2 doz engines. Don`t se ea nickles worth of difference.

The '85 isn't the only model that will generate the warning. It just happens to be the model that you specified at some point.

I would focus on the EPC part numbers. Chances are that price corresponds to size, but no guarantee there.

Diesel911 · #15 04-18-2014, 11:55 AM

Quote:

Originally Posted by psaboic

Ok, the 300D decided it was not going to wait any longer. Today I popped the hood to check the oil while at the fuel station, and my oh my....... Turn out that the nut on the stud with the stripped threads decided to part ways with the rest of the car. End result was that corner of the valve cover was no longer held down. What a frickkin mess! I figure I lost almost a quart of oil and most of it is coating the drivers side of the engine and the firewall.

Got it home, pulled the valve cover off, and since there were no threads left on the stud to try the two-nut method I had to resort to vice grips to back the stud out. Finally got it out, and tomorrow I am off to the hardware store to find a matching thread stud, or bolt and nut.

Guess I will check the valves again as long as I have the valve cover off (did them about 2800 miles ago though so they are probably ok). Then after I get it all back together I get to clean the engine bay.......Yay!

Anyone else replaced one of these studs and stoped a leak successfully? If so and you have any tips, send them along.....I'm POSITIVELY sick and tired of having a leaky valve cover gasket.

I have not had the Stud issue and a lot of People say the Valve Cover Gasket should seal without what I do to them.
I remove the old Gasket and degrease the Gasket area on the Valve Cover with Brake Cleaner.
I put a beed of Silicon Selalant (from the local 99 cent Store) in the groove on the Valve Cover Gasket.
I wipe the Oil off of the sealing area on the Cylinder head and install the Gasket on the Valve Cover and insall the Valve cover gasket with the Nuts sort of 1/2 of what I would tighten the Nuts to normally.

If you want wipe off any excess Silicon Sealant the comes out of the Gasket.
I let it sit an cure like that for several Hours (I live in S. CA. so the outsixde Temp is not an issue when it comes to curing the Silicon Sealant).
When it is cured I remove the Valve Cover+Gasket and spray some Brake Cleaner on a clean Rag and wip off the Valve Cover Gasket sealing edge to get rid of any Oil.
When that is dried I wipe on a thin coating of Silicon Sealant on the sealing edge of the Gasket and install the Valve Cover normally.

Becaues there is still a thin coating of Oil on the Cylinder head sealing area the Valve Cover should not get glued to the Cylinder Head.

If you want to glue it down you can by degreasing the sealing area of the Cylinder head with Brake Cleaner sprayed on a Rag untill the sealinig area is entirly dry.

Concerning the Stud as long as the Threads in the Head are OK some Members have replaced the Stud with a Bolt.
If you cannot find a Stud and want a Stud you can cut the head off of a Bolt (with threads long enough to do that) finline the cut off area so that it threads in OK.
Spray out the Stud Hole with Brake Cleaner and when Dry Loctite the end of the Stud that goes into the head. Use the Double Nutting on the Stud to install it