Oil Leak PITA - Page 2 - Mercedes-Benz Forum
LinkBack Thread Tools Display Modes
post #11 of 14 (permalink) Old 07-14-2015, 08:43 AM
Outstanding Contributor
Date registered: Jul 2010
Vehicle: '85 300D Turbo, '91 420SEL, '92 190E 2.6, '09 C350, '12 E63 Wagon
Location: Arcadia, CA
Posts: 2,964
Mentioned: 10 Post(s)
Quoted: 594 Post(s)
Lifetime Premium Member
But, rereading, I would not put thicker o-rings, just the right size. Thicker means more likely to get pinched and sooner to fail...
jzchen is online now  
Sponsored Links
post #12 of 14 (permalink) Old 07-17-2015, 03:08 PM Thread Starter
BenzWorld Extremist
Date registered: Oct 2009
Posts: 931
Mentioned: 0 Post(s)
Quoted: 59 Post(s)
(Thread Starter)
Here's an update. My mechanic re-did the oil filter gasket today and he said the shop he worked for when these cars were new used 20/50, although he doesn't remember whether it was specially formulated for diesels.

I asked him to critique my work with the previous job and he mentioned the third allen bolt was not torqued as tight as the others and could be the cause of the leak. I asked how you could possibly torque it any better since it was not possible to get a socket wrench on it and his solution was to lift the engine and then all of the bolts are easily accessible. I did not do this before or see any info about it in any manuals. The middle bolt is a real PITA to get to otherwise. He also thoroughly cleaned out the bolt holes on the engine block and mentioned that if you don't remove the oil filter housing and clean it (he keeps it soaked for a day or two to clean) that it is possible oil will come out when you are reinstalling and spoil the work.

He also showed me a few used oil coolers he had lying around in his shop. Apparently, the mating of the oil cooler line with the different metals and excessive diesel vibrations cause damage in the threads. I could see on one of them it wouldn't make any difference in replacing the oil cooler lines if they were leaking as there was not enough strength in the threads to properly mate.

Also, in doing research on Benz forums, it looks like oil pressure runs at around 110psi and my mechanic confirmed this. If this is the case, it would seem that adding any type of gasket sealant would be just about useless for keeping the oil out and only be an aid in aligning the gasket.


Last edited by dkr; 07-17-2015 at 03:12 PM.
dkr is offline  
post #13 of 14 (permalink) Old 07-19-2015, 03:29 AM
BenzWorld Member
Date registered: Jul 2007
Vehicle: 2002 MB C230K, 1985 MB 300T Turbodiesel
Location: Pittsburgh
Posts: 266
Mentioned: 2 Post(s)
Quoted: 9 Post(s)
Thanks for the update. I did not realize from your initial post that you had not gotten good access to tighten the Allen bolts that attach the oil-filter housing to the block. Your mechanic said that he lifted the engine to tighten the bolts. When I did mine 2 years ago, I dropped the steering box (I think that's much easier than raising the engine); once that is out of the way you have clear access to not only remove the bolts without rounding the heads (a big fear of mine given the tight quarters next to the steering box), but also to clean that whole area up of oil that can affect the new gasket installation, and to properly tighten the bolts with a torque wrench. I used a box of Q Tips and brake cleaner to clean out the holes tapped in the block of residual oil and used Loctite to keep the bolts from backing out.
ptbowman is offline  
Sponsored Links
post #14 of 14 (permalink) Old 07-19-2015, 06:07 AM
BenzWorld Extremist
Date registered: Mar 2011
Vehicle: 2001 C240, 1984 300D
Location: Canada
Posts: 951
Mentioned: 1 Post(s)
Quoted: 33 Post(s)
Originally Posted by dkr View Post
He also showed me a few used oil coolers he had lying around in his shop. Apparently, the mating of the oil cooler line with the different metals and excessive diesel vibrations cause damage in the threads.
This is true, but you can get a hydraulic adapter to repair this problem. You tap the oil cooler and thread in the adapter, then screw the new oil cooler lines onto the adapter.

When I replaced the oil cooler lines a couple of years ago I noticed the cooler already had an adapter and it came out with the oil cooler lines. I had to get a new adapter (still available from the dealer, by the way) and install it with high strength threadlocker. It seems to be holding fine and is not leaking at all.
300DFan is offline  
Sponsored Links

  Mercedes-Benz Forum > Mercedes-Benz Sedan Forums > W123 E,CE,D,CD,TD,TE Class

Quick Reply

Register Now

In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Title goes here

video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome