Mercedes-Benz Forum banner

1 - 20 of 44 Posts

Registered
2000 E 320 Wagon + 2002 ML 500 SUV
Joined
1,442 Posts
Discussion Starter #1
Hello All:

I was just hoping to confirm that the correct orientation of this rubber gasket for this 'oil pressure test port cover' is exactly as shown in the pictures I'm attaching here ?

Picture 1 is said to be the side of new gasket as it faces the cover
Picture 2 is said to be the side of new gasket as it faces into the engine

oil pressure test port side faces cover w163 w210 m112 m113.jpg
oil pressure test port side faces engine on w163 w210 m112 m113.jpg


Also, there seems to be confusion on whether to use RTV or similar gasket sealer on the sealing surfaces (edges) where this gasket seals this port cover.

I've read many threads and some say yes some say no.

Can anyone say definitively ? Gasket sealer or NO gasket sealer ?
If so, RTV high temp Oil resistant or Permatex non hardening?

The reason I ask is I just had done this job a month ago, and it began to leak - pour, really - more accurately describes it - and I was 100% sure I had done it correctly.

Torque on those 2 small Torx bolts is said to be 10 or 11 nm or 90-97 inch pounds.

It's possible I put the gasket in backwards, admittedly.

So, I'll open it up again tomorrow, but am tired of this ridiculous effort required to prevent a leak.

This is an example of poor design.

Probably not 1 MB in a 100 ever has a dealer hook up an oil pressure gauge here, yet seemingly 100% of these M113 or M112 engines develop a leak under this cover !

This happened out of state at midnight in a dangerous location, and cost me $350 to have our ML500 towed home.

Thanks everyone for your input !

David in Texas
 

W163 and General M Gremlin
Joined
4,670 Posts
David,

Have you read thru this post? (I have it bookmarked from previous)
 

Registered
2000 E 320 Wagon + 2002 ML 500 SUV
Joined
1,442 Posts
Discussion Starter #3
Yes, Khomer I did. In fact the pics I posted were from post #40 on that thread.

Have you had to do this oil pressure test port cover gasket on your MB's ?

I was baffled that mine could leak so soon after doing it not 30 days ago !

I believe I installed it correctly orientated.

I did use RTV on one side, I think to hold it to the cover while installing.

I also torqued it with an inch pound torque wrench.

Tomorrow I will remove cover & carefully check to discover what failed.

Hoping for some input that may help me get it right the 2nd time around.

The part on our m112 V-6 hasn't leaked.

It's the m113 V-8 that is leaking.

Cheers - David
 

W163 and General M Gremlin
Joined
4,670 Posts
I've only had to do it ONCE on the ML500. I used the newer version (as recommended by an indie friend).
It has never leaked (knock on wood) I read over all the posts before deciding and tackling it. I followed the same procedure.
A warning though - my indie friend did tell me before I started mine, he had to redo a few of these in past, using both older and newer versions - almost like a hit and miss. It's an easy job and one would not think such a simple R&R would go so wrong. :|

I have this in the back of my mind IF I have tackle this again on my daughters ML430 - it's never been replaced.
 

Registered
2003 ml500, 2004 ml350
Joined
2,073 Posts
David sorry for you woes, but where is this cover? Your post is the very first one I ever read concerning it so thanks for the warning.

Wally
 

Registered
Dallas, Texas
Joined
8,464 Posts
Hello All:
Why have you replaced it first time? Was leak alarming at that time? Where gasket came from?

As for poor design. I have replaced it on '99 Ml320 @ 150K
Never on ML 350 with 150k
Never on E320 with 147k
 

Registered
1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
Joined
3,303 Posts
Your orientation is correct assuming you're talking about the gasket on the right in both pictures. Both version of the cover are poorly designed.

I've done this job on two different cars. One started leaking like yours in less than 30 days. The problem is that the gasket is sandwiched in a void between the cap and the engine. The rubber harden and shrink from the heat and then oil leaks out between the cap and engine. When I removed the new gasket, I couldn't believe how hard it got in less than 30 days.

USE RTV ALONG THE EDGE OF THE CAP AND AROUND THE BOLT HOLES!!!!!
 

Registered
1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
Joined
3,303 Posts
Maybe this doesn't happen that often compared to the number of engine produced and the replacement gasket has been sitting on the shelf too long? Hard from old age? Bad batch?
 

Registered
Dallas, Texas
Joined
8,464 Posts
David sorry for you woes, but where is this cover? Your post is the very first one I ever read concerning it so thanks for the warning.

Wally
Here is my '99 ML 320 with radiator and condenser out. Yes, there is wet spot at that cover but nothing alarming.

IMG_4747.jpg
 

Registered
1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
Joined
3,303 Posts
The only purpose of that rubber gasket is to prevent oil from dripping out the hole when the plug is removed to insert the test gauge. They should of extended the rubber part out to the edge of the cap. German engineers don't believe in the KISS principle!
 

W163 and General M Gremlin
Joined
4,670 Posts
Here's an old video in my bookmarks that will show a better view of how the seal fits into the port cover - 2min mark

 

W163 and General M Gremlin
Joined
4,670 Posts
The only purpose of that rubber gasket is to prevent oil from dripping out the hole when the plug is removed to insert the test gauge. They should of extended the rubber part out to the edge of the cap. German engineers don't believe in the KISS principle!
I recall seeing an old post where someone used this port for their DIY oil pressure gauge attachment (on a C43).
 

Registered
2003 ml500, 2004 ml350
Joined
2,073 Posts
Yes, Khomer I did. In fact the pics I posted were from post #40 on that thread.

Have you had to do this oil pressure test port cover gasket on your MB's ?

I was baffled that mine could leak so soon after doing it not 30 days ago !
David

Looking at the way yours is blown out, Right through the round diaphragm got me to thinking. In Witek's photo and your video there is a second plug (internal Torx) installed male thread that installs into female thread of the plate. Do you have that?
 

Registered
1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
Joined
3,303 Posts
David

Looking at the way yours is blown out, Right through the round diaphragm got me to thinking. In Witek's photo and your video there is a second plug (internal Torx) installed male thread that installs into female thread of the plate. Do you have that?
It's not blown out. There is a slit in the round portion for the test fitting to past thru. Like I said previously the gasket is sandwiched in a VOID. The cap is metal to metal to the engine. The cap leaks when the gasket hardens up. That's why I HIGHLY recommend using RTV or a non harding sealant on the caps edge and around the bolt holes.

If you're not going to use the test port, You can even leave the gasket out and just seal the cap onto the engine with RTV or non hardening sealant.
 

Registered
2003 C320 coupe, 2000 ML320
Joined
953 Posts
David

Looking at the way yours is blown out, Right through the round diaphragm got me to thinking. In Witek's photo and your video there is a second plug (internal Torx) installed male thread that installs into female thread of the plate. Do you have that?
I'll take it back.. I've never had the problem and I'll stay out of it..
 

Registered
2000 E 320 Wagon + 2002 ML 500 SUV
Joined
1,442 Posts
Discussion Starter #17
260, yes I'm referring to the 'right side' new gasket in the 2 posted pictures. Ok, got orientation straight.

Witek, earlier on this port cover & gasket were seeping a 'modest' amount of oil.
Frankly I couldn't distinguish how much as the 2 engine oil cooler seals just above were leaking and it all combined. So to 'be sure' I did oil cooler (both) seals, filter housing base seal & this crazy 'oil pressure test port cover' one. Just last month !

Khomer, thanks that video shows it all pretty well. The OP of it also has the rubber gasket inserted into his new cover the correct way, it may be noted.

Wallyo: Those are pictures I grabbed from another thread - not me.

There is a 50/50 chance I got mine backwards, being I did it at night & tired. I did use a modest amount of RTV - not enough to enter engine just to hold gasket to cover while installing.

I note that no one can agree on 'RTV Sealant or NO Sealant' - people are 'all over the map' predicting disaster if you DO or DON'T use sealant.

Maybe as 260 suggested, you can just omit the gasket & use RTV High Temp Oil Resistant Sealant only.

I may just go that route as I can't get a new gasket at our local MB dealer.

Also, One thing that 260 said: It's a trouble spot - and a needless one IMHO !!!

Every other car I've owned, American or Japanese - just about - had a drilled, tapped, plugged 'oil galley port' that was into the block, not some stupid cover with a 'limited life span' gasket.

They couldn't leak due to simplicity.

These Benz engineers are, sometimes, just too enamored of complexity, which introduces 'failure points' into a design.

Thanks for all your help guys !
 

Registered
2000 E 320 Wagon + 2002 ML 500 SUV
Joined
1,442 Posts
Discussion Starter #18
And yes my 'cover' has the plug installed already. It's not loose or leaking.

The more I think of it, the more I like the idea of just using RTV sealant alone, no gasket.

The High Temp Oil Resistant is good for 550 degrees.

I bet that's higher heat resistance than the rubber gasket itself !

Using both could lead to issues once the gasket hardens due to high oil temps and the RTV doesn't harden.

Hmmm...
 

Registered
2003 ml500, 2004 ml350
Joined
2,073 Posts
It's not blown out. There is a slit in the round portion for the test fitting to past thru.
Now that I looked at David's photo for the 3rd time I see the slit on the new cover in the pictures posted.
 

Registered
1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
Joined
3,303 Posts
And yes my 'cover' has the plug installed already. It's not loose or leaking.

The more I think of it, the more I like the idea of just using RTV sealant alone, no gasket.

The High Temp Oil Resistant is good for 550 degrees.

I bet that's higher heat resistance than the rubber gasket itself !

Using both could lead to issues once the gasket hardens due to high oil temps and the RTV doesn't harden.

Hmmm...
You could leave the gasket in. It will not present any problems. You ONLY want to apply sealant on the METAL TO METAL surface and around the bolt holes.

Putting RTV behind the gasket to hold it in place might be your failing point. As you noted, they have different expansion properties. The ridges on the edge of the gasket is suppose to hold it in place in the cap.
 
1 - 20 of 44 Posts
Top