RESEAL OIL COOLER (OIL COOLER LEAKING)
10-13-2023, 05:14 PM
#1
Member
Thread Starter
RESEAL OIL COOLER (OIL COOLER LEAKING)
Working through the list of things the dealership found wrong with my W164 and they stated "RESEAL OIL COOLER (OIL COOLER LEAKING)". Is this a know issue and I can just replace some seals? I poked around the engine bay from above and could not figure out what they referred to. I am guessing it is part of that layer cake of cooling stuff pushed up in the front of the grill and bumper. My best guess is that the gasket would be the problem they are speaking of: More Information for ELRING 524270 (rockauto.com) maybe this one? Looking for tips if this is something I can do without a lift or if I should get my mechanic to do it when he is changing the oil anyway.
Thanks!
Tony
Thanks!
Tony
10-13-2023, 07:49 PM
#2
MBWorld Fanatic!
Join Date: Jan 2009
Location: V E G A S
Posts: 9,094
Received 1,736 Likes
on
1,384 Posts
1922 Ford Model T / no OBD
Weak seals on oil cooler in OM642 engines are know for about 20 years.
Seals alone might cost about $10, but usually mechanics replace whole cooler for about $200.
The kick is that it takes >20 hr of labor to get to the cooler, so with dealer charging above $150/hr that can bring quite big bill.
What are your DIY skills?
The job is not very difficult, but taking big chunk of engine apart require some experience.
Seals alone might cost about $10, but usually mechanics replace whole cooler for about $200.
The kick is that it takes >20 hr of labor to get to the cooler, so with dealer charging above $150/hr that can bring quite big bill.
What are your DIY skills?
The job is not very difficult, but taking big chunk of engine apart require some experience.
The following users liked this post:
gone gone gone (11-16-2023)
10-14-2023, 09:09 AM
#3
Member
Thread Starter
Is there a way to get eyes on the cooler so I can see how bad it is? The dealer gave ****ty stock photos, that are not even the same car, as examples of the problems. I have not noticed a significant drop in oil level on the dipstick, I am wondering if it is even worth the effort.
cheers,
Tony
10-14-2023, 09:23 AM
#4
MBWorld Fanatic!
Join Date: Jan 2009
Location: V E G A S
Posts: 9,094
Received 1,736 Likes
on
1,384 Posts
1922 Ford Model T / no OBD
The cooler is invisible under all the stuff you have on top of the engine and even when you remove stuff to see it, the seals are under it.
But if you see oil dripping via drain hole on driver side, or at the end of the valley, the cooler is the only source of possible leak there.
When you get to the job, make sure you clean the valley perfectly. Other member reported that when dealer did his seals, they let the dirt dropping into oil passage and engine seized couple miles from the shop.
But if you see oil dripping via drain hole on driver side, or at the end of the valley, the cooler is the only source of possible leak there.
When you get to the job, make sure you clean the valley perfectly. Other member reported that when dealer did his seals, they let the dirt dropping into oil passage and engine seized couple miles from the shop.
The following users liked this post:
gone gone gone (11-16-2023)
10-14-2023, 09:27 AM
#5
Member
Thread Starter
The cooler is invisible under all the stuff you have on top of the engine and even when you remove stuff to see it, the seals are under it.
But if you see oil dripping via drain hole on driver side, or at the end of the valley, the cooler is the only source of possible leak there.
When you get to the job, make sure you clean the valley perfectly. Other member reported that when dealer did his seals, they let the dirt dropping into oil passage and engine seized couple miles from the shop.
But if you see oil dripping via drain hole on driver side, or at the end of the valley, the cooler is the only source of possible leak there.
When you get to the job, make sure you clean the valley perfectly. Other member reported that when dealer did his seals, they let the dirt dropping into oil passage and engine seized couple miles from the shop.
I have general oil around the valley, but I don't see a drain hole. I thought it was coming from the oil filter housing. I will poke around when I change the fuel filter. Any pictures of the drain hole or location?
10-14-2023, 02:58 PM
#6
MBWorld Fanatic!
Join Date: Jan 2013
Location: Toronto, Canada
Posts: 3,718
Received 793 Likes
on
545 Posts
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
The leaking oil cooler seals on the OM642 engine have been discussed to death. It is a known issue with the early seals, which have now been revised four times. As @kajtek1 said, it is a massive job (about 20 hours for a factory trained technician and possibly double that if you're doing it on your own) and not for the faint of heart.
Mercedes replaces 27 different seals and gaskets when they do the job because you can't reuse the old gaskets / seals to put things back together properly without ending up with an air leak somewhere, so even if you reuse the oil cooler itself, you'll still need about ~$600 worth of parts. You don't necessarily need a hoist - most of the work is done from the top - but you'll definitely need a warm garage, an empty shelf ore two to keep all the parts that you'll end up taking off and putting back on, and probably three to four full days to get it done.
Here's a link to a more detailed post on the subject: https://mbworld.org/forums/m-class-w...ler-seals.html. There is another link in the original post there that leads to another site with 16 pages worth of additional info on the seal replacement job, so to save yourself a lot of grief make sure you go through everything before you decide to tackle it. It is not a job you can do in an afternoon on your driveway, so you might be considerably better off paying a professional to do it.
Mercedes replaces 27 different seals and gaskets when they do the job because you can't reuse the old gaskets / seals to put things back together properly without ending up with an air leak somewhere, so even if you reuse the oil cooler itself, you'll still need about ~$600 worth of parts. You don't necessarily need a hoist - most of the work is done from the top - but you'll definitely need a warm garage, an empty shelf ore two to keep all the parts that you'll end up taking off and putting back on, and probably three to four full days to get it done.
Here's a link to a more detailed post on the subject: https://mbworld.org/forums/m-class-w...ler-seals.html. There is another link in the original post there that leads to another site with 16 pages worth of additional info on the seal replacement job, so to save yourself a lot of grief make sure you go through everything before you decide to tackle it. It is not a job you can do in an afternoon on your driveway, so you might be considerably better off paying a professional to do it.
10-14-2023, 04:01 PM
#7
Member
Thread Starter
The leaking oil cooler seals on the OM642 engine have been discussed to death. It is a known issue with the early seals, which have now been revised four times. As @kajtek1 said, it is a massive job (about 20 hours for a factory trained technician and possibly double that if you're doing it on your own) and not for the faint of heart.
Mercedes replaces 27 different seals and gaskets when they do the job because you can't reuse the old gaskets / seals to put things back together properly without ending up with an air leak somewhere, so even if you reuse the oil cooler itself, you'll still need about ~$600 worth of parts. You don't necessarily need a hoist - most of the work is done from the top - but you'll definitely need a warm garage, an empty shelf ore two to keep all the parts that you'll end up taking off and putting back on, and probably three to four full days to get it done.
Here's a link to a more detailed post on the subject: https://mbworld.org/forums/m-class-w...ler-seals.html. There is another link in the original post there that leads to another site with 16 pages worth of additional info on the seal replacement job, so to save yourself a lot of grief make sure you go through everything before you decide to tackle it. It is not a job you can do in an afternoon on your driveway, so you might be considerably better off paying a professional to do it.
Mercedes replaces 27 different seals and gaskets when they do the job because you can't reuse the old gaskets / seals to put things back together properly without ending up with an air leak somewhere, so even if you reuse the oil cooler itself, you'll still need about ~$600 worth of parts. You don't necessarily need a hoist - most of the work is done from the top - but you'll definitely need a warm garage, an empty shelf ore two to keep all the parts that you'll end up taking off and putting back on, and probably three to four full days to get it done.
Here's a link to a more detailed post on the subject: https://mbworld.org/forums/m-class-w...ler-seals.html. There is another link in the original post there that leads to another site with 16 pages worth of additional info on the seal replacement job, so to save yourself a lot of grief make sure you go through everything before you decide to tackle it. It is not a job you can do in an afternoon on your driveway, so you might be considerably better off paying a professional to do it.
Trending Topics
10-21-2023, 07:28 PM
#8
Member
Thread Starter
I got the local shop to put my car up on a lift to look around the underside. There is oil on my steering colum linkage going into the steering box. The mechanic says he does not see any other leaking and believes it to be power steering fluid. I may agree with him since my oil level is still on full after about 2k miles. The dealer did not mention PS leakage, but that is very obviously covered in fluid. Where is the weep hole mentioned above for the oil cooler at? 🤔
10-21-2023, 08:59 PM
#9
MBWorld Fanatic!
Join Date: Jan 2009
Location: V E G A S
Posts: 9,094
Received 1,736 Likes
on
1,384 Posts
1922 Ford Model T / no OBD
The drain hole for the valley is on driver side in the area of forward cylinder.
You can't see it unless you lift the car and poke with snake light, but oil on the side of the engine tells a lot.
You can't see it unless you lift the car and poke with snake light, but oil on the side of the engine tells a lot.
The following users liked this post:
MudFoots (10-21-2023)
10-25-2023, 10:49 PM
#11
MBWorld Fanatic!
I was going to do mine myself... but a mechanic from a local Indy works on the side and the owner of the shop was backed up and suggested I use his mechanic. The mechanic charged me $700 to do the job... that was a no brainer for me!
One thing I asked him to do was to apply some sort of high-heat RTV (carefully) to the seals, hoping that would better seal for the long run. Time will tell!
Something I've been pondering, though... if/when I have to do this job again... I wonder how hard it would be to create a block-off plate in the valley of the engine and plug/barb whatever lines need that... and use a regular 'ol oil cooler mounted up in the grill somewhere (or possibly underneath). I'd have to figure out where to tap into the oil supply and where to return it - but I imagine that should all be doable.
One thing I asked him to do was to apply some sort of high-heat RTV (carefully) to the seals, hoping that would better seal for the long run. Time will tell!
Something I've been pondering, though... if/when I have to do this job again... I wonder how hard it would be to create a block-off plate in the valley of the engine and plug/barb whatever lines need that... and use a regular 'ol oil cooler mounted up in the grill somewhere (or possibly underneath). I'd have to figure out where to tap into the oil supply and where to return it - but I imagine that should all be doable.
The following users liked this post:
MudFoots (10-25-2023)
10-25-2023, 11:02 PM
#12
Member
Thread Starter
@DennisG01 Dude!!! I was thinking the same thing! I bet the oil filter mount could be drilled and tapped for some AN fittings by a machine shop. Or even make a new plate and go for a remote filter and cooler. But!!! If it is located in the valley, is it a cooler or a temp regulator. In that case it should be routed to a layer of the radiator.
I was also thinking of fabing a custom bumper to relocate all the coolers...but that is a different story.
I was also thinking of fabing a custom bumper to relocate all the coolers...but that is a different story.
10-26-2023, 09:35 PM
#13
Super Member
Join Date: Jun 2022
Location: WA State, USA
Posts: 604
Received 261 Likes
on
183 Posts
2014 Cummins, 2014 E250 Bluetec
I was going to do mine myself... but a mechanic from a local Indy works on the side and the owner of the shop was backed up and suggested I use his mechanic. The mechanic charged me $700 to do the job... that was a no brainer for me!
One thing I asked him to do was to apply some sort of high-heat RTV (carefully) to the seals, hoping that would better seal for the long run. Time will tell!
Something I've been pondering, though... if/when I have to do this job again... I wonder how hard it would be to create a block-off plate in the valley of the engine and plug/barb whatever lines need that... and use a regular 'ol oil cooler mounted up in the grill somewhere (or possibly underneath). I'd have to figure out where to tap into the oil supply and where to return it - but I imagine that should all be doable.
One thing I asked him to do was to apply some sort of high-heat RTV (carefully) to the seals, hoping that would better seal for the long run. Time will tell!
Something I've been pondering, though... if/when I have to do this job again... I wonder how hard it would be to create a block-off plate in the valley of the engine and plug/barb whatever lines need that... and use a regular 'ol oil cooler mounted up in the grill somewhere (or possibly underneath). I'd have to figure out where to tap into the oil supply and where to return it - but I imagine that should all be doable.
Only problem with that idea is the block off plate still has a o ring of some sorts. Now its possible that you could figure out a better system however its the same problem. The AN fittings ofcourse once good should stay good but the adapter plate is the issue.
The following users liked this post:
MudFoots (10-26-2023)
10-27-2023, 09:26 AM
#14
MBWorld Fanatic!
Join Date: Jan 2013
Location: Toronto, Canada
Posts: 3,718
Received 793 Likes
on
545 Posts
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
You guys do realize that (a) the oil cooler is technically a heat exchanger (you have both oil and coolant flowing through it), and (b) once you replace the seals with the latest revision, chances are they will outlast the rest of the car?
I mean, it's great that you're looking at options that would require less or no maintenance in the future, but the latest (4th gen) seals are not known to leak... so why bother going through the pain and expense of fixing something that isn't likely to break again? Just curious.
I mean, it's great that you're looking at options that would require less or no maintenance in the future, but the latest (4th gen) seals are not known to leak... so why bother going through the pain and expense of fixing something that isn't likely to break again? Just curious.
The following users liked this post:
gone gone gone (11-16-2023)
10-27-2023, 09:36 AM
#15
Member
Thread Starter
I mean, it's great that you're looking at options that would require less or no maintenance in the future, but the latest (4th gen) seals are not known to leak... so why bother going through the pain and expense of fixing something that isn't likely to break again? Just curious.
Cheers,
Tony
10-27-2023, 10:32 AM
#16
MBWorld Fanatic!
A properly designed O-ring seal is about as good as it gets for something removable. Sounds like they may have speced the wrong o-ring compound first time around. (Hard to believe; engine oil is a pretty well known commodity. Blame it on all these new oil specs!) Or, maybe they messed up a dimension, and the new o-ring is a custom size. Improper assembly techniques can damage the o-ring, too. When designed correctly, the pressure you're sealing against tends to force the o-ring into the sealed junction, effectively improving the seal.
10-27-2023, 11:49 AM
#17
MBWorld Fanatic!
I haven't heard any definitive info about the latest (4th) gen o-rings being the be-all, end-all. But honestly, I haven't really dove into that research very much. What I do know is that if we're now on the 4th version of these... I'm skeptical that the o-ring composition is the issue. Meaning, it shouldn't take 4 revisions to get composition "correct". I suspect the issue is more about the mating surface of the block/cooler and/or possibly vibration/movement between the two items. Just thinking outloud there, though.
10-27-2023, 11:50 AM
#18
MBWorld Fanatic!
Join Date: Jan 2013
Location: Toronto, Canada
Posts: 3,718
Received 793 Likes
on
545 Posts
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Yes - the oil cooler has two sets of (two) holes. One side is for the coolant and the other for the oil to circulate. The coolant indeed flows from the block jacket - that's why it is sitting in the middle of the "V" of the block.
There have been four different revisions of the oil cooler seals. The first two were from rubber / silicone and didn't last long (they were orange). The third and fourth revisions are made from Viton (they're purple) and are better, although the third revision has also been known to leak when improperly torqued. The fourth and final revision was a redesign that has a larger seal area and has so far been leak-free. On the third gen seal you can see the exposed substrate material on the inside of the "O" whereas the 4th gen has thicker rings with no exposed substrate on the inside of the "O".
The third-gen seals were the last ones installed by the factory before the OM642 diesel ML production ceased at the Alabama plant where all of the NA vehicles were made. I think the fourth gen seal was released sometime late in 2015 so after NA vehicle production ended.
There have been four different revisions of the oil cooler seals. The first two were from rubber / silicone and didn't last long (they were orange). The third and fourth revisions are made from Viton (they're purple) and are better, although the third revision has also been known to leak when improperly torqued. The fourth and final revision was a redesign that has a larger seal area and has so far been leak-free. On the third gen seal you can see the exposed substrate material on the inside of the "O" whereas the 4th gen has thicker rings with no exposed substrate on the inside of the "O".
The third-gen seals were the last ones installed by the factory before the OM642 diesel ML production ceased at the Alabama plant where all of the NA vehicles were made. I think the fourth gen seal was released sometime late in 2015 so after NA vehicle production ended.
10-27-2023, 11:51 AM
#19
MBWorld Fanatic!
They do something similar for the 6.0 Fords if I remember correctly because they have a problem where the oil cooler in the valley gets clogged up and the first time its a pain to replace (after first time its easier).
Only problem with that idea is the block off plate still has a o ring of some sorts. Now its possible that you could figure out a better system however its the same problem. The AN fittings ofcourse once good should stay good but the adapter plate is the issue.
Only problem with that idea is the block off plate still has a o ring of some sorts. Now its possible that you could figure out a better system however its the same problem. The AN fittings ofcourse once good should stay good but the adapter plate is the issue.
Just kidding, of course. You bring up a valid point. Maybe a semi-permanent adhesive-sealant could help?
10-27-2023, 12:08 PM
#20
MBWorld Fanatic!
Join Date: Jan 2013
Location: Toronto, Canada
Posts: 3,718
Received 793 Likes
on
545 Posts
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
I haven't heard any definitive info about the latest (4th) gen o-rings being the be-all, end-all. But honestly, I haven't really dove into that research very much. What I do know is that if we're now on the 4th version of these... I'm skeptical that the o-ring composition is the issue. Meaning, it shouldn't take 4 revisions to get composition "correct". I suspect the issue is more about the mating surface of the block/cooler and/or possibly vibration/movement between the two items. Just thinking outloud there, though.
10-27-2023, 10:50 PM
#21
Super Member
Join Date: Jun 2022
Location: WA State, USA
Posts: 604
Received 261 Likes
on
183 Posts
2014 Cummins, 2014 E250 Bluetec
A properly designed O-ring seal is about as good as it gets for something removable. Sounds like they may have speced the wrong o-ring compound first time around. (Hard to believe; engine oil is a pretty well known commodity. Blame it on all these new oil specs!) Or, maybe they messed up a dimension, and the new o-ring is a custom size. Improper assembly techniques can damage the o-ring, too. When designed correctly, the pressure you're sealing against tends to force the o-ring into the sealed junction, effectively improving the seal.
Not voice of reason just pointing out something. Get the correct o-rings in there and save your money. Proper O-rings in a properly designed setup are generally the way to go unless its something like a metal to metal flat flange with very even mating surfaces and a ton of clamping force which ya arent going to find on the cooler. Think a head on a engine or two halves of a turbine.
The following users liked this post:
MudFoots (10-28-2023)
11-01-2023, 03:05 PM
#22
Member
Thread Starter
Poking around the engine bay...where is the weep hole for this leak? I found two leaks: one on passenger side front somewhere above the dipstick, the other is drivers side dripping onto the steering shaft right where it goes into the steering box. I think the description I read previously is neither of there locations. Can anyone confirm?
Cheers!!
MudFoots
Cheers!!
MudFoots
11-01-2023, 09:48 PM
#23
MBWorld Fanatic!
Poking around the engine bay...where is the weep hole for this leak? I found two leaks: one on passenger side front somewhere above the dipstick, the other is drivers side dripping onto the steering shaft right where it goes into the steering box. I think the description I read previously is neither of there locations. Can anyone confirm?
Cheers!!
MudFoots
Cheers!!
MudFoots
The following users liked this post:
MudFoots (11-16-2023)
11-16-2023, 10:08 AM
#25
Member
Thread Starter
My leaks (yes, I belive there are two) are more forward on the engine. One seems to be on the passenger side front, higer up, but not valve cover I dont think. It runs down the coolant hose port. The other is drivers side, about mid block dripping directly onto the steering shift where it goes into the steering box. Everything blows around so much that it's all an oily mess. The MB mech thinks it is the oil cooler, the local mech does not think so. That weep hole seems clear.
I recently noticed that the leak goes away as the engine warms up. And that the oil was showing slightly over full on the dipstick. Almost time for an oil change and it is still full on the dipstick.
really wish I had my old shop, this is frustrating!
Thank you all for the input. One day I will get it fixed! 😁 😀
I recently noticed that the leak goes away as the engine warms up. And that the oil was showing slightly over full on the dipstick. Almost time for an oil change and it is still full on the dipstick.
really wish I had my old shop, this is frustrating!
Thank you all for the input. One day I will get it fixed! 😁 😀
