Head gasket. You've replaced a few parts thus far, not much left. Coolant/water in with the oil.

 

We are going to try a cylinder compression test today and watching if the pressure will rise in the cooling system resulting in air bubbles in the coolant reservoir which will mean a head gasket failure.

The milky stuff doesn't always mean a leaking head gasket.

If you live in a very cold region (reason to fill out your location in profile!) and do short drives, its can be a normal occurrence.

I live in Lebanon where the weather is not that cold. 12c in the morning now and 18c in the afternoon. I used to live in Canada so that's not cold by any means. I read a lout about the short drives causing this condensation. If the car wasn't losing coolant, then that would definitely be it. My morning commute is 13 km and takes 40 minutes in traffic. On the way back home, it's 25-30 mins.

It seems like a head gasket. But there is something you might try. Pour a container of Bar's Leak into the radiator (not the over flow unit) when the engine is warm. Then run it for a few days and see if the milky stuff goes away. I am not suggesting this as a fix, but as a way of determining if coolant is getting into the oil via a head gasket. If it is a vary small leak the Bar's Leak will usually block it. There may be some purest on the forum who would gasp at even considering putting something in the cooling system other than water and antifreeze, but I ran an import shop for many years and when other test did not prove conclusive, in would go the Bar's Leak!

Thanks for the suggestion. Not sure if we'll need to try it after the compression test I mentioned above. I definitely don't want to risk damaging the cooling system while chasing the leak.

 

The milky stuff doesn't always mean a leaking head gasket.

If you live in a very cold region (reason to fill out your location in profile!) and do short drives, its can be a normal occurrence.

 

It seems like a head gasket. But there is something you might try. Pour a container of Bar's Leak into the radiator (not the over flow unit) when the engine is warm. Then run it for a few days and see if the milky stuff goes away. I am not suggesting this as a fix, but as a way of determining if coolant is getting into the oil via a head gasket. If it is a vary small leak the Bar's Leak will usually block it. There may be some purest on the forum who would gasp at even considering putting something in the cooling system other than water and antifreeze, but I ran an import shop for many years and when other test did not prove conclusive, in would go the Bar's Leak!

 

I don't think it's about being "purest". Adding such additives into the coolant is a sketchy proposition at best. Usually that stuff ends up clogging the radiator and then you've got a whole other problem.

 

If it cloggs the radiator, it is most likely because the cores are already in poor condition. This vehicle has a relatively new one.

 

Short version: it's the head gasket.*

Long version: the mechanic disconnected the fan and removed it and we ran the engine until it reached 100c so by then the coolant pressure was high. We then started inspecting for any visual leaks or anything.

We were able to identify the head gasket as the problem because we could see the water drip from the exhaust tip.

The car is currently being repaired. It'll cost a maximum of $200 including new head gaskets.*

 

Good luck. Hope that fixes it. Consider having heads milled while they are off. And maybe even a valve job!

 

Yeah if they need milling, they'll get it for sure. We'll see after inspection in the morning.

$200 maximum for repairs? Typo?

No, it's not a typo. Labour is pretty cheap in Lebanon. I pay $10 for an oil change and like $4 to rotate my tires.

He lives in Lebanon......that might not be a small amount there.

Minimum wage is $450 per month here.

 

$200 maximum for repairs? Typo?

 

He lives in Lebanon......that might not be a small amount there.

 

Note to self, ship cars to Lebanon for repairs. At those prices it might cost less to send them, fix them there, then bring them back. How is your guy on transmissions? I sense a business opportunity . . .

Best Regards,

Mike/Florida

 

Note to self, ship cars to Lebanon for repairs. At those prices it might cost less to send them, fix them there, then bring them back. How is your guy on transmissions? I sense a business opportunity . . .

A very active business here due to low labour costs is used car dealers that buy salvage-titled cars from auctions in the US then ship them here where they repair them and sell them for a $2-5k profit.

This mechanic is an engine specialist but his neighbour is a transmission specialist. My dad fixed his W211's 722.6 there for a similar cost.
When I replaced the oil cooler a couple of weeks back, I paid $80 for the part and $20 in labour.

I'm glad you finally found the root of the problem. Head gasket issues are almost unheard of on these engines except when they have been run hot, allowing the heads to warp. I'll be interested to hear what the mechanic find when its broken down.

I'm going to take pics of the head gasket when I go to pick up the car but my car never overheated. The mechanic said that they go bad with time especially since we do get hot summers.

I'll keep you all updated.

 

I'm glad you finally found the root of the problem. Head gasket issues are almost unheard of on these engines except when they have been run hot, allowing the heads to warp. I'll be interested to hear what the mechanic find when its broken down.

 

Latest update:

Upon removal of the head gaskets, no visual cracks or anything was found. Nevertheless, the head gaskets were replaced, the engine internals cleaned thoroughly, and everything put back together. The car started up nicely and we let it run for an hour and we conducted a coolant pressure test and there were no leaks.

I drove the car home (20 mins drive) and next time I started it, the idle was rough and even rougher when I put a gear in it as if it's about to stall but it never stalled. No check engine light and no errors using SDS/STAR.

I drove it back to the mechanic and we pulled both valve covers and removed both camshafts and everything was normal. We did some tests with the coil packs as well. Anyway, after some diagnosis, he had to correct the timing with the chain where it needed one unit of adjustment. He had to skip the chain one tooth underneath the valve covers. This improved things, but the rough idle is still there although less. He told me to drive it for a couple of days, and to bring it back on Friday if the problem is still there. I had paid a total of $233 for this job (150 for labour and 83 for parts) and he said he will get it back to normal without taking a single extra penny.

Now all this was Saturday.

On Sunday, I took the care for a drive and after 30 mins, I got the following errors on the dash:

-Add 1L of oil
-Oil Quality error
-Oil Level Sensor error
-Check Coolant Level

I have since, up until this morning (Monday), added water twice (0.25 L yesterday + 0.75 L this morning) and the milky stuff is back on the oil cap. I also added this morning 1L of oil.

I am going to continue monitoring the car until Friday, but I am not too hopeful. The coolant leak warnings are back, the milky stuff is back, and the car is idling rough. I'm afraid the head gasket was not the cause of the leak, but in all cases, I won't be paying an extra penny until the car is repaired.

I had read somewhere about putting some sort of a safe-to-use dye in the cooling system and driving the car and then checking to see if the dye had leaked somewhere where it could be visible. I might have him do that next if the coolant level warnings don't stop and we're back at square 1.


Anyway, what do you think of all the above?


Oh and I forgot to say that I'm already looking for a 2012 W204 C300 because I've had enough with the CLK. I've done nothing but baby it with maintenance these past 3 years and the repairs keep coming one after the other.

 

Pity to do all that with no result.
Coolant low level could be just the coolant filling air pockets after all the work.
But if you still have coolant and oil mixing then I would go back to the oil cooler,,,what else is there? I know you replaced it before.
Maybe your new cooler is defective ?
I don't think looking for water drops from your exhaust is the best way to diagnose a bad head gasket. Water can be in the exhaust for a number of quite normal reasons.
Using a dye in the coolant won't help unless you think you have an external coolant leak,which I don't think is your problem.

 

I bought the BEHR oil cooler brand new so I highly doubt it's defective but that is a possibility. We can double check that by removing it and conducting a pressure test on it.

As for the dye, if nothing external appears, then we would have to dismantle the engine again and check where the dye has seeped into. Any other clues? Where else can the coolant and engine oil come into contact?

 

In some engines coolant runs through the intake manifold and the gasket can fail there but I don't think that applies to M112.
Nowhere else to mix really,other than head gasket and oil cooler.
Wait longer, try to fix the rough idle,but wait longer to check for sustained coolant loss and significant oil contamination.
Is your positive crankcase ventilation system/breather covers and ports and hoses all clean and clear?

 

To fix the rough idle, I'm going to suggest to the mechanic that we start looking for vacuum leaks and/or forgotten/damaged hose. We'll then go through the spark plugs and their wires and the coil packs. We should be able to spot the problem by then. I read online that if disconnecting the EGR valve's vacuum hose solves the rough idle, then the problem is the EGR valve itself.

Last night, I spent time fiddling with my SDS/STAR and although there were no error codes after scanning, I ran a test called "smooth engine running" and it kept showing me faults for cylinder 5 the most and a bit for 4 and 6. These faults register when the actual value deviates outside the acceptable range. The units were 1/s2 so it's acceleration of the piston I guess? Anyway, that lead me to believe that there's something up with cylinder 5, but it's weird that no error codes were reported and no CEL illuminated.

I then conducted another test which basically disables the two ignition systems, A and B, each at a time. You are then supposed to scan for errors and if something went wrong during that test, it'll register. Well, no errors registered, but the engine was getting rougher obviously during the tests because only 6 spark plugs were sparking at a time.

Regarding the PCV, yes they were all inspected and cleaned when we removed the valve covers. The hoses are 2 years old max since I replaced them so there's no risk that they got brittle already.

I'm hoping that we get a Ta-Da moment where a forgotten hose or something that simple ends up smoothing out the idle without much pain and effort.

 

Maybe there is more than one problem here.

Ignoring the engine oil/water issue for a while, could you be losing coolant because of a worn water pump seal? I can recall losing coolant on a previous car and never finding where it was leaking from by examining the engine bay while parked.

The solution was to apply air pressure to the radiator cap and turn the engine by hand. This rotated the water pump through a 'bad' position where water appeared. The reason that I could not find any signs of water when stationary was that the fan blew the droplets of water such that it vanished completely.

Most workshops will have this tool and it's certainly worth checking out.

 

Yeah I read in a couple of places that this thing could be happening with the water pump. I am definitely going to add this to the list of things to check. Thanks a lot.

 

Below are pictures of the old head gaskets along with the oil cap from this morning.

 

The Check Coolant Level warning is now always on regardless of the fact that the coolant reservoir is topped up which leads me to believe that the sensor is faulty.

In addition, the car is now needing water/coolant every day leading me to think that something's up with the engine block/surfaces because before the attempted repair, it would take 3-4 days for the coolant to get low. So I guess when the block was removed and reinstalled, the crack got bigger and it's leaking more water now.

 

Re Coolant level warning,,make sure your windscreen washer reservoir is full.They are on the same circuit.
Is there oil in the coolant?
Were the heads crack tested and/or tested for straightness or machined?

 

I did not know they were on the same circuit since I never let the washer fluid get low so I've never seen the warning. I'll top it off for sure.

There is absolutely no oil in the coolant. I look every time before I add water and it's just clear water.

The heads were not crack tested but they got washed with gas and visually inspected and nothing seemed abnormal. We may need to remove them a second time and have them crack tested and leak tested and pressure tested and machined....

What's weird is that I have owned the car for more than 3 years now and it never overheated before and still does not overheat whatsoever.

 

There is only one other place that coolant can get into the engine oil - there is an O ring between the timing chain rear cover and the engine block and if this fails the coolant goes into the oil.

To get access to this O ring one needs to remove the timing chains and that cover.

Seal No 38

 

Thanks a lot of the suggestion. I will add it to the list of things to check.

 

Ref post #25, I am interested in the white stuff showing on the removed gaskets. The WIS document details precisely where the special sealant should go - and I wonder if your gaskets have followed the rules. Of course we cannot see what remained on the CH.

To remove/install the CH is quite a tricky procedure, with a number of pitfalls that are included in the WIS. Some of this additional information is on documents referenced on the r/h side of the WIS document and is not included here.

1. The path and procedure for use of the Loctite 7200 sealant on the CH.
2. The sequence for removing/replacing the CH bolts.
3. The procedure for checking bolt elongation
4. Reference to 'porous surfaces'. (I am not sure what this is about?)
5. The advised tightening torques.

If you would like to see any of the additional WIS drawings referenced, please advise here.

 

So I'm at thw mechanic and here's what we thought. Before we changed the head gasket, the car was loosing 0.5-1L of water every 3-4 days. After the head gasket change, the car started loosing almost 1L every day which leads us to believe that the movement in the heads caused this.

So, in order the check the timing cover o-ring and the heads and the block, we decided to remove the entire engine and inspect it meticulously.

If we find the o-rings are bad, we will replace them and put the engine back. If not, we will inspect the heads and and test them for leaks. Otherwise, we might just put a new engine for $500-600.

I'm staying at the garage while this is unfolding so I'll keep you all posted.

 

The first o-ring we got to was ripped as seen in the picture below.

We're continue to dismantle the timing cover to get to the second o-ring.

 

I can now confirm that the passenger side o-ring was ripped and the driver side one was swollen and leaking as well but the passenger side one was far worse.

We confirmed that too by the oil pan which had the milky stuff in its bottom, in a decent quantity, on the passenger side.

The timing cover is out now along with the oil pans. We'll clean everything, replaced the o-rings, and put it back together and hopefully that's it.

 

Well done for finding the problem, you guys certainly work quickly.

Judging by the corrosion where the coolant pump fits I would say the cause of the problem was due to not using the correct coolants and a poor maintenance schedule.

I always maintain if one wants an engine to last a long time then apart from regular oil and filter changes it is critical to change the coolant every 3 years using only Mercedes coolant/good water mixture.

Very good pictures by the way and good luck:smile

 

Well done for finding the problem, you guys certainly work quickly.

Judging by the corrosion where the coolant pump fits I would say the cause of the problem was due to not using the correct coolants and a poor maintenance schedule.

I always maintain if one wants an engine to last a long time then apart from regular oil and filter changes it is critical to change the coolant every 3 years using only Mercedes coolant/good water mixture.

Very good pictures by the way and good luck

Thank you for chiming in. I always used MB coolant and the correct mixture but when the car startee losing coolant since summer, i would just top it off with water.

Maybe this is something I inherited from the previous owner.

Anyway, we're now done cleaning all the oil pans and the timing cover. There were barely any burnt oil or sludge at the bottom. Very clean engine since I only use 229.5 oils with a 6,000 km interval.

The lesson I learnt from all this is to never buy a Merc with more than 50k km on it. Beyond 100k, the repairs are too much to justify the cost. I bought the car in September 2014 from Germany with 100k km and I've done nothing but baby it throughout.

 

Just FYI Valvoline™ ZEREX™ G-05 is what MB uses, it just cost less. Also the mixture is not as important as people think. The fluid is needed to lubricate the system and in some case keep the water from freezing. The truth is that water conducts heat better than antifreeze.

 

Well done to Rorypff for knowing and advising about these o rings.
xsever, this is a very rare problem,unfortunately just bad luck.
Most MB CLK320 even well over 100,000 km are very reliable and cheap to maintain if you diy.
Don't give up on your car.

 

Thank you very much indeed to Rorypff in specific, and to everyone else in general for all your help. You really saved me a lot of time and guessing and money. I owe you one!

 

I still think these M112 and M113 are some of the best and simplest engines that Mercedes has ever produced. I have heard of these engines doing 500 000kms without major maintenance.

I use 229.5 Mercedes oil also but change it every 2 years or 16 000kms:wink

Plugs every 160 000kms, coolant every 3 years and brake fluid every 2 years.

Oh and transmission oil every 60 000kms and diff oil every 10 years or 160 000kms.

Engines have zero oil leaks.

 

That's all I hear all over the internet, but if I were to post here everything I've changed on my car, people would go crazy as it's a pretty extensive list. Anyway, that's behind us now.

Thanks a lot for all your help and support. Much Much appreciated. I owe you one!