W221/C216 Transmission Oil Cooler

[Richard Moakes]

A word of caution to all W221 / C216 owners, be sure to check the metal fluid lines running to the additional transmission oil cooler mounted in front of the AC condenser. Mine rusted out and started leaking, the replacement of which has turned into a cascade of parts replacement.

 

[Botus]

its a std merc design flaw, out of sight covered in road salt

people need to remember driving ANY car in salted roads is a recipe for instant disintegration - you need to wash the rot inducing filth off your vehicle - its made many times worse as they put plastic rubbish covers hiding components, last 20 years most metal is rubbish from china that makes 1970's Italian metal look durable, and the fact your local council now put 3" of salt down every time the temp drops to 5C - never might a little bit in know black ice black pots and steel that could cope

 

[alexanderfoti]

Yes very common, and frustrating.

 

[mattkh]

its a std merc design flaw, out of sight covered in road salt

Would a coat of a 'water and salt repellant' on these pipes reduce the efficiency of the cooling down I wonder.

 

[alexanderfoti]

Would a coat of a 'water and salt repellant' on these pipes reduce the efficiency of the cooling down I wonder.

Yes, cover everything in Dynax UB before its rotten, and it will stay like that. Re-apply every 2 years

 

[Richard Moakes]

I plan to use ACF-50 on the new lines, also replacing every rusty screw/fastener with marine grade stainless items

 

[mattkh]

I plan to ....... replacing every rusty screw/fastener with marine grade stainless items

A prestige car manufacturer took this to the extreme and found that stainless wheel bolts kept becoming loose.

 

[Richard Moakes]

A prestige car manufacturer took this to the extreme and found that stainless wheel bolts kept becoming loose.

Oh yes, stainless can be quite soft, but the screws for every clip holding the pipes snapped due to corrosion when I was dismantling it, so will replace all of those with stainless.

 

[Botus]

Would a coat of a 'water and salt repellant' on these pipes reduce the efficiency of the cooling down I wonder.

no the are feed pipes to the cooler, not the actual heat exchanger

 

[Richard Moakes]

Discovered something interesting today, EPC says the o-rings on the cooler are A0199976945 (11.8 x 1.78)

However it is wrong, they are A019996045 (9.25 x 1.78)

Just in case anyone else ends up doing this job at some point in the future

 

[Robin Bloemberg]

A word of caution to all W221 / C216 owners, be sure to check the metal fluid lines running to the additional transmission oil cooler mounted in front of the AC condenser. Mine rusted out and started leaking, the replacement of which has turned into a cascade of parts replacement.

View attachment 79124

Hi,

I'm new here and just registered to ask you a question:
Did you replace the cooler lines yourself? Can it be done without removing the radiator and disconnecting the A/C lines?

Cheers,
Robin.

 

[Richard Moakes]

Hi,

I'm new here and just registered to ask you a question:
Did you replace the cooler lines yourself? Can it be done without removing the radiator and disconnecting the A/C lines?

Cheers,
Robin.

Hi Robin,

I did replace them myself, but it ended up being a replacement of the radiator and condenser as well. The pipes wrap around the side of the radiator and I couldn’t find a way to remove them without removing the condenser and radiator. Once I removed them, it was obvious they had seen better days so I replaced them as well.

I then assembled the whole “pack” with the pipes fitted and slid it into place as a complete unit.

 

[DSK]

Good to know, I will have these inspected for good measure at the next service.


Sent from my iPhone using Tapatalk

 

[Robin Bloemberg]

Thanks Richard,

Good to know you can slide the radiator/condensor pack in as a whole with the transmission cooling lines installed.
There is YouTube video of someone who leaves the condensor in place to avoid discharging the A/C, but it looks like a nightmare frankly. My car is a W221 AMG with power steering cooler and ABC (suspension) cooler mounted to the condensor as well. Hopefully I can unclip those and leave them in place.

 

[mioba]

Its a great leaf trap and then moisture trap down there on all mercs. I get into the habit of cleaning the rad - soft brush and car wash each year and getting those leafs out

 

[Richard Moakes]

The clip that holds the transmission cooler lines to the radiator tank has a bolt that is pretty much impossible to remove with the pack in the car. Pre-assembly seemed the only sensible choice and was no doubt how it was done in the factory.

Other issues you may encounter, the AC line fitting at the condenser on my car was seized never to separate, I spent days trying to separate it using heat, violence, but the aluminium had corroded the joint solid. I ended up cutting it off in the end and getting a new line to the receiver dryer in the inner wing. You may also find the radiator core support is rusty, so be ready to either replace it or give it a good clean down and apply rust proof paint etc.

You can remove the PS and ABC cooler and leave them hanging without disturbing the fluid connections, just be careful with the plastic clips that want to break as soon as you look at them.