My friends, it took me a couple of weeks but I got this done. Never attempted something this complicated ever and by following the instructions here and using some logic I got it done and it is great. No more coolant loss and I went ahead and changed all the seals. Valve, head gasket, valve stem, did the sparkplugs and cables and my girl is running beautifully. Thank you for all of you who took time to post and explain to us noobs here how we should not be afraid of getting our hands dirty and showing us the way. Thank you.

 

Would you mind posting some pictures? I would like to see the process, mainly because there are no videos of it online that I can find, and everyone says it is an engine out only job on an ML due to clearance.

I have however seen someone remove the front cross section of the body for better access.

It would be nice just to see what entails of a job like this.

 

The cause of coolant in the oil needs to be sussed, and fixed ASAP. My head gasket problem, OTOH I allowed to go until I couldn't avoid fixing it. ( Loosing too much coolant in a very short period of time)

 

Head gasket failure is very rare unless the engine had a horrible over heating issue.
I have never seen one go from normal driving until the owner told me about a setious
over heating issue.

 

That’s what I was getting at.

My main point in asking is that, with how many of these engines are running around, surely some of them are being neglected, and are still running with this o ring issue.

Is it really that detrimental of an issue? Coolant in oil is obviously a big issue, but at this scale, is it really that worrying?

 

The issue really comes from when it isn't actually the head gasket. You can likely use a scope camera to check if the seals are intact. Also perform a cylinder compression test.

 

I asked about this in another thread I have going, but since there are millions of these engines around it is worth a shot asking...

Is this issue really that detrimental to the engine? I am all for fixing things the right way, but if you keep on top of your coolant and it isn't a huge leak, does it really matter all that much I mean, surely there are many people ignoring this and their engines are still running great.

Taking the timing cover off in a W163 is a difficult task from what I have read. Not impossible, but I would definitely rather not, I live in an apartment and would be in big trouble.

 

In my ML, I found that I had a coolant loss, due to what I presumed to be head gasket. No coolant in oil, and no oil in coolant. But steady coolant loss, causing the need to add coolant every other day. I managed to isolate the culprit to the #2 cylinder via leak down test. Replaced the head gaskets, and all is well. with over 279,000 miles on it.

 

Noodles, is there any way we can categorize by the engine itself? While this may be somewhat useful, the motor encompassing a lot of the minutiae would be much better organized and easy to locate. . . I myself have struggled at times to find relevant information to my clk.

 

If you post your C55 issues in the wrong section again there all be moved or deleted.
Stick to the W203 section. There is no help for you in the W211 section or the W163 section.

 

Hey what’s up guys. I have a 2005 C55 AMG with the same issue. Is there ANY way to do this with the motor inside the car. Possibly by removing the front clip? I genuinely do not want to take this motor out

 

As I have 4 of these M112 engines (many years, altho not high mileage) I read thru this with interest. And a bit of concern altho I have none of the indicators.

This repair was on @deanrantala 1998 ML320. Is there any chance that MB switched to a different compound seal at some point, as was done for the oil cooler seals on the early GL OM642?

 

First I would like to say thank you a million times for this write up. I have a 2003 C32 amg with 167k miles and was experiencing coolant loss every 3 days. I did the common problems (intercooler and radiator) and also changed the oil filter housing/cooler only to still have the same problem. Then I found this write up online , pulled the engine, removed the timing cover to find that one o ring was missing like yours and the other was broken apart and swollen. Changed both seals, also replaced rear main, valve cover, front crank seal and other various seals and the engine is leak free. I believe we will be seeing more of these issues as the mileage on these vehicles increases. It’s a big job but definitely worth it as this engine will run for a lot of more miles. Thanks again!

 

Welcome to BW.
for finding your needed thread.

The forum index is organized / grouped according to Mercedes chassis / platform designation, usually one letter followed by 3 digits / numbers, and the section covers all engine / versions the chassis came with.

With year and model of the car, it's easy to find your forum section, click FIND YOUR FORUM SECTION
Followup by posting in the W203 chassis forum, and make sure you fill-in your vehicle profile.

Please click Complete your Vehicle Profile to add 2003 C32 Amg, so it will show next to every future post under your avatar.
Members are not likely to search for the one post the model of the car is mentioned.

The forum section archives have a wealth of DIY / technical information.
When researching an issue in your section / before posting, you can also Search your chassis forum archive via the 'Search Community' box on top.

 

It's been a while.

Is this really that frequent of an issue on all of the M112/M113 engines including those up through the 2006 models?

Don't really hear too much about this issue affecting that many folks, besides this thread.

But, maybe that's because most of the vehicles with these engines are already in the junkyard for other reasons.

 

LOL,
They have it at any O'Reilly parts store.

 

A clear light golden color. Or if a complete flush was done
at a point in time then the Blue coolant. Zerex G48 for blue
and G05 for the golden color.

 

How’s this?

 

Why is there green coolant in the year M113.
Thread being moved to R129 forum.

What color should it be?
I started a separate thread in the R129 forum.

That's what was on the shelf at 7-11.

so what color should it be?

 

Why is there green coolant in that year M113?

 

Why is there green coolant in the year M113?

That's what was on the shelf at 7-11.

 

See ya

 

I wanted to document an issue that is becoming more and more common on the M112 & M113 engines now that the years are starting to pile up.

Over the past few years... I have heard of many individuals dive into a head gasket job because of "oil in coolant" or "coolant in the oil". Many perform the entire head gasket job only to see the issue remains.

I have noticed this issue as well on 5 different engines now. 3 of my own personal vehicles and 2 from friends/family.

The reality is: the head gasket itself rarely fails. Most usually, the cause of this issue is one (or both) of the 2 main rubber o-rings that seat between the timing case and engine block.

There were reports years back (when I had my repair shop) of this "rare issue". But I would like to reassure everyone here: this is no longer a rare occurrence. Due to the nature of what happens, this issue will become ever-more common as we move forward. Here is why: the material used for those o-rings actually swells over the years. On one side, that o-ring is exposed to coolant. On the other, it is exposed to oil (even though the factory applies a very thin coat of silicone, that silicone breaks down and eventually gets onto the o-ring).

Once this o-ring swells enough, it literally swells INTO the passage-way where the coolant flows and eventually... gets pushed out of it's spot by the coolant-flow and washed out-of-place and ends up somewhere in the engine.

It usually comes to rest in the cylinder head.

Even a couple engines that did NOT have this issue - but were tore down for other reasons: those o-rings were not far from having failed the same way.

Here are some pictures...

Just removed this timing cover from my 1998 ML320:
View attachment 2711990

Notice this passage is missing the o-ring?
View attachment 2711991

This is where I found the o-ring... this seems to be the most common place it comes to rest: the cylinder head.
View attachment 2711992

A comparison of the original o-ring next to a new (MB OEM!) one.. Notice how severe the swelling is? The o-ring literally swells up INTO the pathway of coolant until the coolant washed is out of it's position. Luckily, they apply a tiny amount of silicone from the factory on the oil side, so when this happens - the leak/contamination is often more subtle and not a catastrophic event. Nonetheless, it WILL begin to leak oil into the coolant or coolant into the oil.
View attachment 2711993

Again, these particular photos are from my 1998 ML320. HOWEVER - I have seen this failure (or about-to-fail) on just about every 112/113 engine I have opened up over the past 3 years (and I have opened several). So this issue affects any chassis with the M112/M113 engines.

Keep in mind also: these o-rings are essentially the same material that your oil level sensor o-ring is made of. If you have ever had to change the oil-level-sensor o-ring, you can bet these timing cover o-rings are not in much better shape! And consider this: after 150-200k miles.. virtually every M112 or M113 engine has had to have the oil level sensor o-ring replaced by now.

I believe over the next few years, this issue will crop up more and more and these o-rings continue to swell and get washed out-of-place. As this happens, many will be led to believe that the head gasket has failed when it has NOT. Unfortunately, if you happen to pull the timing cover and find one of the o-rings missing, the only safe thing to do is pull the heads to ensure you do not leave this floating around in the block as it could cause serious issues eventually if left where-it-is.

Anyway.. I wanted to get this out there so others know: if you pull the heads.. PULL THE TIMING COVER AS WELL!!! Chances are almost 100% that - given the age of these motors now - those o-rings are either near-failure or have already failed.

Hope this helps others.

Maybe make this a sticky somewhere?

Tags: M112, M113, Cylinder Head Gasket, water coolant in oil, oil in water coolant, still leaking, timing cover, leaking

You may have just saved me a lot of heartache. I am in the middle of changing what I believed was a blown head gasket on a 2006 S430. Never ran hot but it did sit for 6 years. The timing concern me enough that I’ve paused and spent some time studying. (I am a novice). I will now redirect to the timing chain cover. I do have a question on timing. I watched a YouTube that seemed very helpful BUT the guy turned the crank counter clockwise which I did possibly 6~10 turns. Have I screwed my timing up???? Thank you for sharing.

 

Please Complete your Profile by adding the year and model of your car, so it will show next to every future post under your avatar.
Members are not likely to search for the one post the model of the car is mentioned.

 

Thanks all for posting. I am hoping that these posts will serve as a guide to some other poor owner somewhere in years to come. (As it did me...)

Personally, I flushed out pre rebuild. Admittedely only with the garden hose. But i also ran the engine to get it hot before each flush. AND yes, brown pudding is the best way to describe what came out in my case. (Like a thick chocolate mouuse). I cleaned all parts with copious amounts of water/degreaser while dissassembled also. And purchased a new coolant reserviour.

Unfortunately, i still have trace amounts of oil left (I dare say because i only used a garden hose and not HOT water. - rookie error) however, its very minimal.

A very thin oily slime on your finger when you dip the reserviour. but its enough to make me cautious and want to clean it out. Plus when it happens again in another 15 years, it would be handy to have a clean reference point to begin with.

I will follow the advice above.

Thanks once again everyone for responding.

Adam

 

While the MB flushing agent is a fine choice, I would like to point out:

Depending on how bad the contamination is, no amount of flushing agent is always going to get the job done. Other times, it may - but will easily take several rounds.

Also remember this: while technically you could run a flushing agent through the system 4 or more times, what is your time worth?

At the dealership, MB often will NOT FLUSH/CLEAN certain components out if the contamination is severe enough. They replace. The components in particular here are: radiator, heater core, and possibly some of the hoses. Why? TIME.

Each flush requires you:

1. Fill a cool engine with fresh water
2. Add solution
3. Start engine and bring up to temp
4. Wait several minutes
5. Turn off
6. Wait several minutes
7. Drain
8. Inspect
9. Hope it is clean, if not - repeat.

If you need to repeat this more than a couple times (as could be the case in moderate-to-severe contamination), you can easily spend many hours on this.

Now - I would like to point out that my initial flushing advice is based on the assumption you have moderate-to-severe contamination. For those who have not worked around a repair shop and seen first-hand what "moderate-to-severe" means, I will explain.

When you have a large (1" or thicker) layer of emulsified oil laying in the bottom of the of your expansion tank. Perhaps a solid quarter to half-inch layer built up around the entire inside of the radiator. Or the coating of emulsified oil along the inside of your hoses is 2 or 3 times thicker than the wall of the hoses themselves... If this is the case, forget about a flushing agent as step-1. Much more time-efficient and effective to break out the good-ol soapy water and give it a proper cleaning. If you have never seen a truly "contaminated" system, imagine a medium-brown substance with the consistency of pudding. Sometimes, it can be so bad to the point of almost completely blocking.

If all we are talking about here is a light residue and some signs of a light film floating along the top inside the expansion tank - skip the comprehensive cleaning I outlined above. Use your choice of flushing agent. Honesty, the Prestone stuff is 1) just as effective, 2) available at any walmart, or parts house and 3) plenty safe and poses zero risk of any damage to your MB cooling system. If you feel better using the official MB-branded stuff, that is absolutely fine.

One last point here regarding the use of distilled water (I know the purists are just boiling over by now)... Tap water from the garden hose is not going to be in your cooling system long enough to cause any "deposits" or damage. And on the topic of the flushing water for a manual clean/flush - I want to point out again... The HOTTER the water, the better. If the contamination is really bad (lots of the brown pudding-like paste stuck everywhere), lot's of hot water is the key to washing it out. Also note that when the contamination is this bad - a simple flushing agent would be foolish since you may wash/shift large chunks of this emulsified oil into other parts of the cooling system. Which again - is why I prefer the manual method while the engine is out or when I am doing a head gasket job that suffered severe contamination.

But again... if all we are talking about is light residue... A simple flush is just fine. The cheaper Prestone is more than effective, but use the MB stuff if that is your preference. And do NOT be afraid to drive around town a day or two with it in the system to ensure it really loosens up the residue if the residue was slightly nearing the "moderate" side.

Cheers!

 

Use a Mercedes flushing agent .i have a part number but it is for the old type engine coolant cleaner .
for oil in coolant MB part number 001 986 21 71 500 grams , And for scale in coolant part number 001 986 21 71 500 grams

 

Mercedes sells a de-oil chemical in case you want to use the real stuff. It isn't cheap of course. The factory manuals have a procedure for de-oiling the cooling system if contaminated.

 

G'day @deanrantala,

I wanted to say thank you for your help. I own a 2005 ML350 with a W163/722.6 and had the dreaded coolant/oil soup mix. Upon investigation and removal of the water pump, i managed to feel around for the non existent seals and well... the next steps were obvious.

Fast forward several months later and my ML is rebuilt and purring like a kitten with an all new seals kit throughout.

I do have one last question... What would you recommend is the best way to clean out the coolant system. I still have some residual oil kicking around in there and am curious as to what is the best way to clean out the system without destroying all my hard work?

I have read everything from expensive coolant flushes to dish washing detergeant will work. Deagreaser mixed with water. And clothing laundry detergeant. It is a maze of pitfalls that i would rather avoid. Any advice is appreciated.

I have pressure tested the radiator. It holds 15psi easily, so I am fairly confident its residual oil. (Also test drove for an hour and neither the oil/PS fluid/ATF dipped at all). Which i would have expected to happen if there was a leak of some form...

Any help would be appreciated.

And thank you again. your post answered and solved my problem beautifully. Thank you

Adam

 

G'day @deanrantala,

I wanted to say thank you for your help. I own a 2005 ML350 with a W163/722.6 and had the dreaded coolant/oil soup mix. Upon investigation and removal of the water pump, i managed to feel around for the non existent seals and well... the next steps were obvious.

Fast forward several months later and my ML is rebuilt and purring like a kitten with an all new seals kit throughout.

I do have one last question... What would you recommend is the best way to clean out the coolant system. I still have some residual oil kicking around in there and am curious as to what is the best way to clean out the system without destroying all my hard work?

I have read everything from expensive coolant flushes to dish washing detergeant will work. Deagreaser mixed with water. And clothing laundry detergeant. It is a maze of pitfalls that i would rather avoid. Any advice is appreciated.

I have pressure tested the radiator. It holds 15psi easily, so I am fairly confident its residual oil. (Also test drove for an hour and neither the oil/PS fluid/ATF dipped at all). Which i would have expected to happen if there was a leak of some form...

Any help would be appreciated.

And thank you again. your post answered and solved my problem beautifully. Thank you

Adam

Any good engine flush ($8-$12 should be sufficient. If you had a LOT of contamination, it may take 2 or 3 flushes.

Also, some responsibility falls on the person or shop who performs this repair - especially when you have a LOT of contamination. It really helps when the engine is out and you have everything broken down to perform the following:

• Manually flush out the heater core with a garden hose. Pouring a bucket of very HOT water and lots of Dawn Platinum into one end of the hose followed by a good rinse-out with the garden hose. Repeat this 2 or 3 times.
• Do the same with each hose. Submerge each hose in a large bucket/pale of scolding hot water w/ Dawn and squeeze the hose (working the soapy water around). Rinse completely.
• While heads are removed, it is very easy to clean 99% of all the water passages in the block AND head with soapy water and a bottle brush.
• Same goes for radiator.. hot soapy water w/ dawn.

Obviously, if you already have the engine re-assembled - some of these steps will not be valid. But some of it you CAN do....

• Drain the coolant
• Remove upper and lower coolant lines from radiator
• Remove 2 coolant lines going to/from on heater core
• Flush radiator and heater core each with hot soapy water. Have a buddy hold their hand over lower outlet and pour the hot soapy water into the top by bending the hose upwards. Fill, drain, rinse with garden hose. Repeat. Do the same for the heater core. You can unhook the 2 lines that come to/from the heater core from the back of the driver-side cylinder head and the circulation pump (pass side fender). Hold one line upwards and use a large funnel to pour the hot water into. Rinse completely with garden hose.
• After both radiators are completely flushed, fill with water and flush solution. Regardless of what the flush bottles say, drive the thing a good 40-80 miles. Do this when you know there is no freezing weather expected. You should have very little (if any) contamination after doing this twice. You may find virtually no contamination after just a single flush.

Some other notes on the flush:

• Stick with Dawn Ultra or Platinum. The Ajax and other brands just do NOT cut oil like Dawn - trust me on this.
• Be sure to flush the dawn out very well. Also note: the Dawn is only for the manual flush - DO NOT PUT IT IN YOUR ENGINE AND RUN THE ENGINE.
• Stay away from degreasers. Most engine degreasers have Sodium Hydroxide (a.k.a. Caustic Soda). If you are un-familiar with Sodium Hydroxide, let me explain what it is: a mild acid that reacts rather aggressively with aluminum and is also rather harsh on seals/orings. It is also the main active ingredient of Oven Cleaner. Depending on which degreaser you are talking about (one of my favorite is the Zep industrial).. they will even turn aluminum a darkish color due to oxidation.
• Coolant tanks are cheap. Spend the $20 for a new one AFTER you are done flushing the system. The tank typically does not get enough "flow" to really make any amount of flushing effective. Again, the tank is dirt cheap.
• No need to change the thermostat if it has recently been replaced. However, the o-ring for the thermostat is only a dollar or two. So if you pull the thermostat and flush the block out with fresh water, be sure to use a new o-ring. Again, they are dirt cheap - do not risk it.
• While the Zerex G-05 and MB original fluids are excellent choices - do NOT be afraid to head to Wal-Mart. They now sell a generic version of the Teal-colored (branded as "Teal Color, For European vehicles") that is the same exact chemical that was originally used on that vehicle. It is only $10 a gallon and pre-diluted. You only need 3 gallons to fill a bone-dry M112 and right at 3 gallons to fill a bone dry M113. Stay away from the generic green stuff. While it will not cause catastrophic issues, it DOES allow mild corrosion at various connections and seal points throughout the coolant system on these vehicles. You will NOT see this issue with the generic teal-colored stuff, zerex g-05 or official MB fluid (either the older blue OR golden colored).
• The hose clamp for the upper hose is very deceiving. If it is not perfectly straight around the neck of the thermostat, it will slowly dribble. I know this sounds easy, but trust me - very easy and common mistake to not get that clamp perfectly flat around the neck.

Hope this helps.

-Dean

 

Finally got some spare time to finish this job up. Figured I would share a few more pics and some notes....

The heads rarely ever give much trouble on these. A quick check with a machinist ruler showed the heads were about as perfectly flat as could be.

I did do a deep clean and re-lapped the valves w/ a drill and some compound.

** I WOULD LIKE TO TAKE A MOMENT TO ADDRESS A SOURCE OF CONFUSION AS WELL **

I have had a few other DIY-ers come over when I had the shop and ask about "sealant around the cylinder head gasket" and the whole "defects in block and/or head" that is mentioned in WIS.

TAKE A LOOK:

This defect is about 1MM deep, and spans several millimeters!

Here is another:

The defect shown above is right between the water jacked and oil passage!

I have ordered BRAND NEW HEADS from MBUSA that had this!

The block can often be found with the same defects. If you see such issues, DO NOT MACHINE THE HEAD. I know.. this sounds nuts but... that is why WIS mentions the sealant around the head gasket.

Here is how I apply the sealant:

I follow the same general pattern on the other side of the HG once I lay it down - just before setting the head.

I usually do not bother w/ the MB sealant (made by locktite). I had a chance to chat w/ some of the guys at Permatex a while back and discovered something: the Permatex "Right Stuff" is the same thing. They are both a "high solids" fast-set RTV that is highly resistant to oil and adheres like crazy to aluminum and magnesium both. I prefer the 90-minute one - gives me a little more working time to assemble everything -VS- the original one that sets in as little as 30 minutes.

MB uses the Locktite one on the production line because: these engines are assembled, filled and run within hours in the factory. They do not have time to wait 24-hours to fully cure.

You are not the factory. And I highly doubt anyone here will be able to re-assemble this engine AND have it back in the car and ready for service in less than 24 hours. Fast-paces shops often need things like valve covers to be ready-for-service in short order - and that is understandable. That said... the "Right Stuff" is a premium RTV that seals these engines perfectly and I have NEVER had a leak from a joint sealed by this stuff. Trust me when I say: I have personally put over 100K miles on [Mercedes] engines sealed by the stuff and never had the first issue.

Anyway... Got her all back together and buttoned up. Full belly of Mobile1 5-40, nearly 3 gallons of G-48 spec coolant (the G-05 works, too). Just stay away from the green. It certainly causes corrosion buildup around all the gaskets, orings and where the hoses connect to the nipples.

Took it for a 20 mile trip this evening - smooth as butter.

 

Spent a little time this afternoon to clean up the engine block a little bit.

Gonna be another week until the head gaskets & valve stem seals come in.

I will try to upload a few more pics as I go along for those who like engine pr0n.