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S211 E220CDI coolant leak

dan1w

Active Member
Joined
Nov 28, 2007
Messages
97
I have a coolant leak that I can’t trace the source of. It started a few days ago requiring topping up twice on a 300 mile drive and now requires topping up after about 15 miles driving.

There is a drip coming from the second undertray back so the leak is presumably to the rear of the engine block. I replaced a hose a few years ago between the exhaust heat exchanger and crankcase, there is another hose there that doesn’t look in the best condition but doesn’t seem to be in the right place to account for the drip.

It’s dark now so have bunged some radweld in to hopefully get me to work and will continue to investigate tomorrow, if anyone could suggest any likely culprits that would be appreciated. Thankfully it’s not freezing weather!
 
It’s dark now so have bunged some radweld in

Oh god :(

common leaks on the OM651:
- Water pump
- Fuel filter housing
 
Oh god :(

common leaks on the OM651:
- Water pump
- Fuel filter housing

Thanks but it doesn’t seem to be coming from those areas.

The front undertray came loose and got mangled on the motorway some time ago so was disposed of, so I don’t think either of those areas could direct the leak to drip onto the second undertray.
 
@pmcgsmurf any ideas?
 
Had a chance to get a better look at this and it doesn’t look good.

Fluid on N/S wishbone mount so thought great it isn’t going to be too hard to access but turns out that is a small transmission fluid leak, great.

Topped up coolant reservoir and let car warm up and no sign of leak, then turned heating to max and suddenly plenty of drips from either side of the transmission fluid pan, appears to be coming from the interior side of the lining.

Really hoping this isn’t a dash out job or in other words RIP car.

Ideas?
 
Anyone had this fail

mine failed, and they often do.... but I’ve never heard of them leaking - they tend to seize up and one side of the car runs hot air whilst the other cold.
 
What a muppet. Pretty sure the drip was a red herring and was just the air con drain.
 
What a muppet. Pretty sure the drip was a red herring and was just the air con drain.

could be
 
Found the hose, it was leaking between EGR cooler and vacuum pump which was the first one I looked at, couldn’t see it leaking though until I wedged the accelerated down with a piece of timber. God knows how the leaking coolant ended up in the rear undertray.

Annoyingly this is right next to the hose I had to have replaced on holiday a few years back and remember having to pay a few hours labour for the mechanic to get to it, but it’s a lot better than a leaking heater core.

If anyone has changed this pipe and can let me know how little I can get away with removing to get to it it’d be appreciated.
 

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