Khan 55

Good day members. Sadly I experienced this issue this past weekend. Thank the Lord, it happened around the corner from my home so I was able to cruise home for less than a km and switch her off before the temp went up.
I was hammering the car as usual when a jet of water emitted from the bonnet on the passenger side. Which then turned to steam and then heat in the cabin. All the water leaked out of the engine. Later I topped it up and started her up. Found coolant leaking from an engine outlet on the RB rear or passenger side Left side which goes into the firewall, below the windshield wipers and crosses over to I don't know where. I have googled it and found this issue on CL55's only where people have replaced a heat exchanger or some elbow looking pipe. Anyone know if its the same on a W209 model? They are the same engines which leads me to believe that it could be the same.


Your help will be highly appreciated.

insame1

When I think of coolant and firewall I think of the heater core. Any pics?

Khan 55

Will be posting up a partial DIY for this. I need to buy a special plier for the clamps and get the part from agents.

insame1

so whats the problem then?

GatorMB

There are quite a few heater hoses, Pump and hot water valve that can leak as well.

The best way to find it is with a pressure tester.

The heater core does leak on any car and on these it normally leaks antifreeze out the AC condensate drain tube.

I bet it is a heater hose or failed clamp.

Khan 55

I visited local dealership yesterday to which the dumb guy was arguing with me that only two pipes are used on my vehicle from the diagram shown. Wanted to order me one that connects to the engine rear.
The thing is as we all know that a C55 and CLK55 use similar parts on certain places. They also share the same parts that a smaller engine model would use example a C200 or whatever.
So the plastic connection I have issues with is between the fire wall, connecting from rear of engine to the heat exchanger behind the driver side cluster. Lucky for me I had stripped all the panelling from the wiper motor so I could see the routing of the pipe. The p/n is 203 830 26 96 listed for a C230 Merc. So I wait for Lord only knows what. Then the guy gets the part number I gave him and shows it to me. I inspect it and he says this is the wrong number you gave me listed for the C230 and not your CLK55. Still shows me my car details, colour, order date and model and trying to persuade me into thinking I'm wrong. Anyway I inspect and indeed it is the darn pipe with the fitting I want. Sadly it wasn't as cheap as the first pipe price. I paid around R650 for it which is +-$46


As I mentioned, I will post up photos of the procedure I went about to get to it. I am ordering special pliers of a Kennedy brand for this pipe clamps as a normal water pump plier isn't gona really help me nor will I be happy with it.

Khan 55

how does one insert photos from album into the post?

GatorMB

you have to resize it ms paint to a minimal pixel arrangement normally less than 250mb size.
Click the photo of the mountain icon to search your pc or phone files.

cell phone photos are extremely large and will never fit.

Thanks for posting the part #. Did the part fail from stress like a broken motor mount or just crack with age? hmmm

Khan 55

I will do that. Thanks Gator. Yeah I suppose its old age. You can decide once its up. I doubt its motor mounts coz mine don't seem bad at all and I suppose this pipe cant really move much back and forth. It seems since the time I owned it which is now 5 months, I had thought it contained coolant in the system well atleast the expansion tank seemed to. But I am afraid maybe it wasn't enough. None the less I have bought 6litres to fill with 6 litres of water as the owners manual calls for 12litres of coolant. 6.6l is concentrate. A technician at MB tells me they use 2litres water to 2litres concentrate. Couldn't he just say 2:2 ratio. But the funny thing is, the bottle says to use 1litre concentrate for every 3litres of water.

Khan 55

managed to upload the photos

Khan 55

Firstly you can remove the housing above the battery for the cabin filter.
I then removed the cover above the fuse box. Then I removed the three nuts holding down the wiper arms. The arm wont come right off. You can gently tug upward or open them in the position you normally would to clean the windscreen and try again. They will eventually come off or you can spray Q20. I then removed the connector going to some module for the windscreen. It probably is a rain sensor detector or something that works in conjunction with the wiper motor. I then removed this entire panel from under each corner of the windscreen. Just make sure to move a pipe out of the way like I have in the above photos. You could remove the water drains here as well or gutter drains but mine were pretty tight on so I gently removed the panel ensuring not to damage them. The panel should then come up after you pull it pass the wiper motor studs for the wiper arms. Then remove the two bolts holding down the wiper motor assembly and remove the white clip that holds the harness of the motor. You will then see part of the wiper motor on the driver side is bolted down to the cover beside the fuse box. Remove it as well. Please note this little guy can be a pain. Ensure you have a magnetic finger nearby in case he decides to run for it. Unfortunately I did not remove the wiper arm motor assembly but you could if you remove the three bolts holding it down as the wire is insulated into the motor assembly. I just put it one side.
Then you will be able to see the pipe that I have mentioned above with the part number on it. Now I am awaiting a tool I ordered to complete this job but there is a clip that you can pry off after the engine, before the firewall which I have indicated in the photos. You would first need to locate the red drain plug on the radiator and collect the old coolant for disposal to prevent high pressure water, if any present in the system, from injuring you. The new pipe connects into there so the clip needs to be removed. One can then battle like I probably will to change the entire pipe from the body of the car that joins behind the dash into the heat exchanger or you can just undo the clamp immediately after the firewall on the plastic connector joining to the pipe and be done with this repair. Once I complete it. I will take the remainder photos. But as of now, that's how far I got as I don't wana use water pump pliers but the right plier known as a angled flat band hose clamp plier.

If anyone has time to check their plastic connector out, lemme know the condition of yours and your mileage on the vehicle as I am sure this failure would contribute to poor maintenance of the cooling system as well as engine mileage.

Khan 55

So I repaired this problem yesterday. Everything seems to be fine now.
It is better to just have the normal flat band hose clamp pliers as it would help in all of the cases u need to undo the clamps.
So I started by removing the 10 sized nut on the aircon pipes above the hose in question. You can then gently tug on the two metal pipes and they will come out. Now you can easily access the clamp on the hose going to the heat exchanger.
The other side of the hose I used a water pump plier or if you have a flat band hose clamp plier it would be the best. NB not the angled type used here.
I highly recommend you remove the clamp holding the hose from the RB rear to the small 90degree elbow connector as you would need to reuse it later. Only way you gona get them apart is to pull equally with ur arms horizontally in front of you. Thats how hard the rubber o-ring in the damaged connector held.
Dont try prying it like I did as you wiuld probably then need to buy the engine hose at the rear as well for that small plastic connector. None the less luckily I hadnt damaged it so I removed it along with the broken connector. Pulled it really hard apart and then just reconnected it to the new one.
NB it isnt necessary to undo the clamp by the heat exchanger unless you wana change the hose as well. I battled to pull it off with the little space I had so I just left it.
I will post up the remainder photos during the week.
Thanks for your advice and for reading my post

Khan 55

ok here is the remainder of the photos. The plastic hose connection will need to be removed entirely to pull them apart. If you have any further information please ask.

DamienLBC

Great write up! I will be referencing this thread today (staying home from work) as I have the same problem! just one question...how did you get the outside edges of the cowl/collector to free up from the window?

Khan 55

Hey there and thanks for your kind words. I simply put my hand under the section that's more away from the pillar and since its a softer than harder plastic, was able to get it out from the edge section. I must admit now that I have reinserted it after this job, it just doesn't sit flush with the windscreen. Not that it matters as the water still drains out the sides behind the fenders but maybe use a light smear of black window silicone to hold down the top edge along the lower section of the windscreen. It didn't have any to begin with so I thought it should be okay reinserting the plastic panel without the silicone to which my results have proved me wrong. I did store this part in the boot during the time of repairing this problem.

Sid Polar

Thanks... for the PN.

Warner Parker

I own a 2006 A209 (CLK 55 AMG) the fix is simple . You will need to purchase a "y" shaped kit from Advance Auto's self help section the kit comes with clamps and a piece of 5/8 inch hose you will need 4 or 5 more clamps to ensure every connection is sealed. You will need to cut an inch off of each end of the straight pipe. The end that angles off can be left on to help reach the return line. You might have to cut your original hose tha goes to the heater core to make it fit. The cost of the kit is $15.87. Or you can make one out of brass pieces from Home Depot for $32.00 and find out like I did (it's too big) this should be a permanent fix. Why the Mercedes Benz engineers decided to use plastic on such a critical piece in such a hard to get to area is beyond me.

Warner Parker

replace all plastic pipe with aluminum iron brass pieces before they burst and leave you on the side of the road.

benzingtherules

This post and the pictures are awesome. Thank you all. My question is.... (sorry I dont know all the proper titles) I removed the two hoses on the connector on the firewall side. Should I now disconnect the hose clamp and hose from the connector outlet on the engine side near the throttle body? Then once the connector is separated from the wall, how do I remove that plastic housing that the hose was connected to (that connected to the connector) I believe that has to be used on the new connector.

waveterrorist

If someone could provide the stupid 3 way plastic connector part # I would greatly appreciate it..

benzingtherules

A2038300396, 2038300396

Shribe

This post is still helping out 3 years later! Mine went last night. Is the bottom of the wiper motor taking these out? Thanks KHAN 55

Olivers_Rage

WOW I cant believe it, as Khan 55 stated it happened exactly like he described to me this evening, was doing a bit of spirited driving all of a sudden my widescreen fogs up causing me to pull over,Ace Ventura style driving by looking out the side window. Its dark, the engine is hot and there is steam and water coming out leaking onto the road from the passenger side( RHD car).
I cant see where exactly due to steam darkness and heat but I could see the source is behind the firewall under the windscreen.

Luckily I too was not far from my house and risked driving home keeping my eye on the temp gauge like a hawk and the was dash going crazy with coolant low warnings.
Got the car home and waited for things to cool down and upon inspection it was the pipe running from the back of the engine to the firewall and connects to another one on the other side of the firewall and i think into the heater core. also had to deal with a drenched battery tray as coolant was damming up in there and had to suck it out with a straw(all 3.5l of it oh my back!!!). I didn't have a 12V power source nor a long enough socket extension to take battery and clamp out hence I had to sucky sucky and it was oh so sucky :-(

I will reference this article to do the repair

Thanks to Khan 55

naj959

Just wanted to give a thank you to @Khan 55 for the excellent diy. After passing a car on my way home, I noticed the check coolant error starting going off and my first though was I must have bust a hose. This was probably 2 miles or so from my house so I proceeded to cautiously drive home since the temp had not gone up and there was no steam or any other alarming symptoms. I did start feeling moisture in my foot well and I knew something was up. A block from my house I see steam starting to rise from directly in front of me on the driver side of the hood. I turn my heat on full blast and limp down the block to my place. After a cursory google search I came across this thread and felt like this was the most likely cause of my leak. I proceeded to take off the wiper assembly along with the cowl (may have been attached with silicone because it was a real hassle to get off) and there's that darn plastic part with a gaping hole on the top. The failure is identical to the pictures listed in this thread. Perhaps a defect or poor engineering? I'm off to the dealer tomorrow to get a replacement and new hoses. My connector was so brittle that both pieces of plastic inserted in each heater hose snapped when I took off the clamps. I don't think I can fish them out since they've practically melded into the hose. With some luck I hope to be up and running tomorrow night. Man that thing was a pain to get out. I ended up using hose clamps to push the clip on the connector past the firewall. Those things did not want to budge.

naj959

Can anyone tell me if the 90* plastic elbow comes with the 3 way connector or If that has to be ordered separately. I've been looking at photos of the part number listed above and it looks to be a separate piece.