220estate
New Member
Hi everyone,
Am hoping someone can shed some light on an apparently intractable problem. I picked up a relatively high-mileage (300.000km) 2010 C220 Estate half a year ago, paying a bit below market value in the knowledge that it needed some attention (the classic oil leak on the oil filter housing, as well as a noisy timing chain - both of which I replaced successfully).
Unfortunately the car has been plagued with endless visible and invisible coolant leaks, which seem to pop up in new areas as soon as one problem has been fixed. By now, I have fixed VISIBLE leaks by replacing the coolant return line to the overflow reservoir (cracked plastic fitting), the reservoir itself (pinhole leak under the triangular sticker on top), the O-rings that seal the 3 thick pipes running from the radiator to the engine after they all seeped coolant one after the other, the radiator itself (pinhole crack found where the top pipe connects), the seal inside the EGR bypass valve (some corrosion visible), the diesel filter holder (turned out it was not actually leaking but the plastic was very brittle and clearly on its way out), the thinner coolant pipe that runs from the side of the engine block up to the diesel filter housing (the pipe split catastrophically), another U-shaped pipe between the diesel filter housing and the EGR cooler (split), and finally the plastic connecting piece on the rear firewall which leads to the heating system (the piece was totally brittle and split in two).
All this has happened over the last 6 months. The car drives fine but after 50 or 100 or 200km the coolant level starts dropping again and I find myself searching for yet another leak. The only other possible culprit I have not yet replaced is the water pump, but I have checked it very carefully a number of times and there is no sign of a leak.
Yesterday I noticed the level dropping again and I am really at my wits' end. I have happily owned 9 or 10 Mercedes over the last 25 years and have never experienced anything like this. Half the engine seems to be made of extremely brittle plastic parts that crack and break when you as much as look at them. Is this normal? Could this particular car have severely overheated at some stage making everything extremely brittle?
Just to add: I have also (twice) replaced the coolant reservoir cap, thinking that possibly it was not letting excess pressure escape and therefore causing various pipes to fail by over-pressurising the coolant system - no noticeable change. And finally, when I first got the car last winter, on wet weather cold starts there was a fair amount of white condensation from the exhaust on startup - not dramatic but more than I have seen on other cars. I eventually concluded this to be from the EGR bypass sucking water into the intake and it seemed to resolve itself after replacing that particular seal, but that may have also been due to warmer temperatures. At one stage I started wondering about a possible head gasket problem, but there is no oil in the water or vice versa, and the engine has run perfectly for the 7000km I have managed to do in between repair missions on both short and long trips. So, again ... not sure what to think but it doesn´t seem likely.
Thanks if you have managed to read all the way to the end. Any advice or suggestions would be most welcome!
Regards -
Peter
Am hoping someone can shed some light on an apparently intractable problem. I picked up a relatively high-mileage (300.000km) 2010 C220 Estate half a year ago, paying a bit below market value in the knowledge that it needed some attention (the classic oil leak on the oil filter housing, as well as a noisy timing chain - both of which I replaced successfully).
Unfortunately the car has been plagued with endless visible and invisible coolant leaks, which seem to pop up in new areas as soon as one problem has been fixed. By now, I have fixed VISIBLE leaks by replacing the coolant return line to the overflow reservoir (cracked plastic fitting), the reservoir itself (pinhole leak under the triangular sticker on top), the O-rings that seal the 3 thick pipes running from the radiator to the engine after they all seeped coolant one after the other, the radiator itself (pinhole crack found where the top pipe connects), the seal inside the EGR bypass valve (some corrosion visible), the diesel filter holder (turned out it was not actually leaking but the plastic was very brittle and clearly on its way out), the thinner coolant pipe that runs from the side of the engine block up to the diesel filter housing (the pipe split catastrophically), another U-shaped pipe between the diesel filter housing and the EGR cooler (split), and finally the plastic connecting piece on the rear firewall which leads to the heating system (the piece was totally brittle and split in two).
All this has happened over the last 6 months. The car drives fine but after 50 or 100 or 200km the coolant level starts dropping again and I find myself searching for yet another leak. The only other possible culprit I have not yet replaced is the water pump, but I have checked it very carefully a number of times and there is no sign of a leak.
Yesterday I noticed the level dropping again and I am really at my wits' end. I have happily owned 9 or 10 Mercedes over the last 25 years and have never experienced anything like this. Half the engine seems to be made of extremely brittle plastic parts that crack and break when you as much as look at them. Is this normal? Could this particular car have severely overheated at some stage making everything extremely brittle?
Just to add: I have also (twice) replaced the coolant reservoir cap, thinking that possibly it was not letting excess pressure escape and therefore causing various pipes to fail by over-pressurising the coolant system - no noticeable change. And finally, when I first got the car last winter, on wet weather cold starts there was a fair amount of white condensation from the exhaust on startup - not dramatic but more than I have seen on other cars. I eventually concluded this to be from the EGR bypass sucking water into the intake and it seemed to resolve itself after replacing that particular seal, but that may have also been due to warmer temperatures. At one stage I started wondering about a possible head gasket problem, but there is no oil in the water or vice versa, and the engine has run perfectly for the 7000km I have managed to do in between repair missions on both short and long trips. So, again ... not sure what to think but it doesn´t seem likely.
Thanks if you have managed to read all the way to the end. Any advice or suggestions would be most welcome!
Regards -
Peter
