W204 Facelift Diesel Oil Cooler / Transmission Cooler Leak (photos)

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SH0X

Member
Joined
Jun 13, 2012
Messages
56
Location
London UK
Car
W204 C250 D Coupe
Hello guys, its been a while. Ive searched all over for info on this but I cant find much (relating to my type of cooler )

The car is a w204 facelift c250 cdi (om651 engine I believe )

Screenshot_20190224-005711_Gallery.jpg Screenshot_20190224-005715_Gallery.jpg Screenshot_20190224-005719_Gallery.jpg

There is a trickle leak from the oil cooler - the hoses that connect to the cooler at the top (there are 4)
I know this as you will see in the photos - oil sits on the oil cooler itself.

I cleaned this up and it seemed to have gone away but its back now or perhaps I didnt notice it as much.
It was there 6K miles ago (slight trickle) when I bought the car.

Im wondering if anyone knows about this type of cooler and if a renewal of the seals would be sufficient enough to resolve?

I searched the forum & found other threads stating 9hour job on some models? My cooler is easily accessible.

Thanks in advance
 
I had a leak from there too, ended up replacing the cooler as just replacing seals didn't resolve it but replacing the cooler wasn't too difficult. but then it is a bit of a job getting the transmission fluid back to the correct level without a dipstick to check.
 
I had a leak from there too, ended up replacing the cooler as just replacing seals didn't resolve it but replacing the cooler wasn't too difficult. but then it is a bit of a job getting the transmission fluid back to the correct level without a dipstick to check.

Thanks for your message
Did you buy the seals from MErcedes and get them done or did it go into the dealers? Im wondering if its DIY level to change them (mine has a trickle leak from the lower left one)

I considered swapping the cooler, but the car doesnt overheat or act up at all its just a trickle leak & I fell changing more than required could cause issues - start simple and see how it goes was the method I was going for
 
I changed them myself. It is a diy job just be careful when screwing the hard pipes back on make sure they screw back in all the way by hand and then just use a wrench to tighten. When I done mine I ended up draining the gearbox so was easier for me.
 
I changed them myself. It is a diy job just be careful when screwing the hard pipes back on make sure they screw back in all the way by hand and then just use a wrench to tighten. When I done mine I ended up draining the gearbox so was easier for me.
Thanks really helpful as I was trying to work out how the hard metal pipes fitted into the hex nut area - one of my pipes is loose and causiong the slight trickle leak - and now your message makes sense to what possibly could have happened to mine. FUnny as this car had FMBSH and a recent gearbox service with them £2000 bill so perhaps the techs forgot to do this properly.

Thanks again Ill report back on my findings either way
 
I just bought a NRF transmission cooler. The unions used are a smaller size so the pipes dont fit .its a big difference. Can i reuse the old unions ?
 

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