Coolant leak on c220 CDI w203?

MikeSWw203

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Jan 29, 2022
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C220cdi W203
Good morning all,

My w203 seems to have a coolant leak from somewhere but I cannot see where.
It doesn't over heat, but when it gets to the level in the pic attached I get a warning.
This is happening at least once a month, so it's going somewhere.
It's looking dry around the tank but I do hear hissing when it's had a run.
I cannot see anything white in the oil cap so I'm not sure where it's all going.
It's massively overdue a service tho.
I have no way if getting it up on a lift or getting under it really.
20220512_064913.JPG
 

m80

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Viano, 651 2014. W211 646 (for a short while)
1st place i would look would be around the back of the water pump pulley.
Clean and dry the area, I use white spirit to spray, and monitor.
 
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MikeSWw203

MikeSWw203

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C220cdi W203
1st place i would look would be around the back of the water pump pulley.
Clean and dry the area, I use white spirit to spray, and monitor.
Thanks, will look at that today.
If that is the source, is it a bad job?
 

m80

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Viano, 651 2014. W211 646 (for a short while)
On the om646 engine it's relatively easy.
I syphon out as much coolant as I can, assuming I don't intend to replace it.

The water pump bearing may have play,
the seal in front may be passing.

It's a good time to replace the aux belt, and check the pulley's.
 

ALFAitalia

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Looking at the staining on the reservoir it could be the pressure cap failed. On my Ford Ranger I had this issue....I was loosing water from no obvious source. Then I noticed the staining from dried on coolant.....one new cap later and sorted. Hopefully yours will be that simple......
 
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MikeSWw203

MikeSWw203

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Jan 29, 2022
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C220cdi W203
It's very wet under where that would be, since I am not car mechanical as a person and cannot get under it, would this be an expensive job?
The tank was dry on top (I had filled it before I drove, so the damp part may have been spillage) after a 25 mile drive but under the belts it was wet, I have a 100m drive today so will wipe the reservoir clean and see what it looks like after 20220519_065236.JPG 20220519_065242.JPG
 
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MikeSWw203

MikeSWw203

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C220cdi W203
Was clean as a whistle after 200 mile drive, must be the pump :(
 

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