Mercedes CLA Forum banner

61 - 70 of 70 Posts

·
Registered
Joined
·
542 Posts
Well, on my way to a Dr. appointment 3 weeks ago the center dash where the spedo shows, "Engine overheating, pull over and turn off engine immediately." You guessed it, Water pump. I knew there was a very small leak somewhere, but could never find it. I assumed it was some porous casting somewhere and my dealer is 50 miles away. The car had 37,800 miles on it. 3 months out of warranty. Well, being fairly experienced at repairs I tackled the job. I am sure that Mercedes wouldn't totally approve,l but it is back together and working well for the last two weeks. The job is horrific! At times I even thought of pulling the engine ( I have an engine lift). I'm not sure a private shop would tackle the job and if I was one I would turn it down. The underside of the pump has a valve, actuated by vacuum, where there was a leak around the piston that finally froze it in the closed position resulting in instant engine overheating. You can see that it is a common failure point by searching the net. There is also a video of a mechanic putting one in. I avoided some disassembly with a work-around or two.
Where is the video of it being put in?


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
6 Posts
As far as I can see the thermostat is doing OK. I hate to say pics would be useless as everything is buried under the turbo. OK, most of the work arounds. First was deciding which way the pump would come out so that would determine what had to be removed. I wanted to avoid taking the big tubes that to the air cooler off if possible. The pump has to come out the very front of the car. 4 lines to the turbo have to come off and be replaced or the seals replaced as needed. Once those are off you have to get the belt off too. Tensioner is buried under the passenger motor mount. I ended up supporting the engine and taking off the motor mount with my air gun. You have to get in the passenger side wheel well cover to get some out. This helped get one of the lines to the pump out (here is the bad part) that I ended up cutting with a Dremel, as it winds around the front of the engine an under a bunch of stuff. There also is a large line off the pump the winds around the passenger side of the engine and winds around the other way. Cut that with the Dremel also. Now you can disassemble the front plastic part of the pump and slide it out. I disassembled the plastic front on the new pump and put it in and reassembled it. The lines that were cut were carefully cleaned, and the smaller line was spliced using one of the flexible hoses from the used water supply line to the turbo. This was coated with water pump RTV and double clamped on both ends and then cover with a used piece of flexible heat shield, I found a high temperature high pressure hose (www.amazon.com/gp/product/B07BS37W41/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1) compatible with antifreeze and spliced the large line together, Water Pump RTVed it, double clamped it on both ends and also covered it with heat shield ( www.amazon.com/gp/product/B003HIPBJM/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1) Put the lines to the turbo back, Belt, engine mount. Etc. Going on two weeks with no leaks. some air pumps out of the radiator but that's it. There is a video on this if you want to see the whole disassenbly that was recently posed. If it starts leaking I'm getting rid of the car! They should make one of the engineers do this and see how they change the design!
 

·
Registered
Joined
·
11,118 Posts
@brian 913
thank you so much for posting your process notes ... you're right the germans will have a fit with the solution ... "vaas eez daas??" as my european cousins would sneer at me with.
if and when i need to execute this hope i can find a way to avoid cutting and pasting ... though from what i've seen they would probably go ahead and replace the hoses/clamps as well (the extra allowed billing for materials and time for related repair/maintenance components to avoid related part failure rework etc etc cuz then they cannot bill that to hq)
glad you reconfirmed it is the belt driven unit ... for some reason many think our m270s have an e pump? ahhh wth maybe theres an aux circulation baby unit for eco mode (like the gearbox?)
may i ask where you sourced the h20 pump and what was the p/n stamped on it? i ask cuz i am sure they had to go thru revisions as there was a rash of early failures - which is odd since the m270 has been around since 2011.
come to think of it i did bother an engineer when i was at the factory in germany and asked about service and maintenance access ... oil changes were noted as a breeze (as we all now know) but she did confess some of the "breakable" items may need a "gymnast" ("der gymnastiker" as she said with a wicked smile ... oh so typical)
 

·
Registered
Joined
·
6 Posts
@brian 913
thank you so much for posting your process notes ... you're right the germans will have a fit with the solution ... "vaas eez daas??" as my european cousins would sneer at me with.
if and when i need to execute this hope i can find a way to avoid cutting and pasting ... though from what i've seen they would probably go ahead and replace the hoses/clamps as well (the extra allowed billing for materials and time for related repair/maintenance components to avoid related part failure rework etc etc cuz then they cannot bill that to hq)
glad you reconfirmed it is the belt driven unit ... for some reason many think our m270s have an e pump? ahhh wth maybe theres an aux circulation baby unit for eco mode (like the gearbox?)
may i ask where you sourced the h20 pump and what was the p/n stamped on it? i ask cuz i am sure they had to go thru revisions as there was a rash of early failures - which is odd since the m270 has been around since 2011.
come to think of it i did bother an engineer when i was at the factory in germany and asked about service and maintenance access ... oil changes were noted as a breeze (as we all now know) but she did confess some of the "breakable" items may need a "gymnast" ("der gymnastiker" as she said with a wicked smile ... oh so typical)
I did replace the lines to and from the turbo and flexible hoses came with the coolant ones , The cooling lines come with new hoses and clamps and heat shielding. If only Mercedes included flexible couplings on the two i cut, as they did with the coolant hoses to the turbo it would cut the job in half. The pump came from my Mercedes dealer stock. He did note to me that this apparently has become a popular item that Mercedes has "disappeared" it to prevent dealers from keeping them in stock and only send them to dealers when they have a specific work order going. I will check on the part number, but the number ends with a "C" so I think this is the third revision. I would not ever expect any car to have a catastrophic failure like this at my mileage.
 

·
Registered
Joined
·
11,118 Posts
well in terms of part designs making sense i know they have a compromise chart and you guessed it the bean counters rule that one.
there have been quite a few instances of water pump failure though the catastrophic part is a tempered one - they want you to have to stop for a tow : to protect the motor and avoid even more costly repairs ... else it will be the old days of “i am almost home just a few more miles” and by that time its a cracked block and warped heads.
and with the ridiculous tolerances and multiple interrelated subsystems that need to sing in tune together (especially the piston to wall design critical dimension) forget about the limp it home without water cooling trick it will be one big blob.
saves them costs during warranty and limits out of warranty bills ... kinda makes sense from that $ based angle.
i eye the water pump and turbo lines areas like a hawk ... the first sign of anything funny and its parts shopping time!
 

·
Registered
Joined
·
11,118 Posts
Oh dont remind me ... my plugs are due soon
But the “definitive guide” somewhere on here helps
Its not too bad ... but i do miss my old engines where i can see and touch everything w/o dismantling stuff
 

·
Registered
Joined
·
6 Posts
The Intake manifold between the air box and the intake to the Turbo is very difficult to re-fit due to having a wire bundle cross it with little clearance. Another great design!
 

·
Registered
Joined
·
11,118 Posts
yup you went thru the same pain

you could make some modern art with all those fancy clamps
 
61 - 70 of 70 Posts
Top