2014 C220 W205204 OM651 Adblue Coolant leaking/Pouring out

[ama singh]

Hi,

We have this car in the family and has been running without any issues, apart from coolant light which started coming on in the last couple of weeks.

Had coolant level warning light appear on dash again this morning, I ended up pouring a few litres of coolant in to the expansion tank. Car was used for a short trip, upon return coolant warning light came back on, ended up putting another 2-3 litres of coolant in.

Car is now jacked up with engine undertrays removed, looks like the coolant is pouring out of a plastic pipe which appears to be going to a cooler unit just above the steering rack.

I'm not familiar with this engine, looks like it may have a water cooled interchanger for the charged inlet air?

Would be grateful for some guidance please.

Thank you

 

[steveq]

That sounds like a bad leak.
The coolant pump and the fuel filter housing are the two most common sources of coolant leaks.
However both tend to start as slow leaks and gradually get worse.

If it is that bad it should be fairly obvious. Just because a part of the engine is wet it doesn't mean that it is the source of the leak -- it could be coming from higher up and leaking down.

Better to check when the engine is running but cold as the coolant will evaporate quickly when the engine is hot.

 

[alexanderfoti]

Yes air/water IC on these, but the circuit is separate from the the engine coolant, so that is probably not the leak.

Possible you are looking at the oil/water heat exchanger?

I Agree its probably leaking from the fuel filter housing (which has coolant flowing through it) and leaking down the IC.

 

[ama singh]

Water was pouring down the plastic air inlet pipe post charge air water cooler.

Turned out to be a failed fuel filter housing gasket, see attached picture.

Hope the MB replacement has a more durable design.

 

[alexanderfoti]

Water was pouring down the plastic air inlet pipe post charge air water cooler.

Turned out to be a failed fuel filter housing gasket, see attached picture.

Hope the MB replacement has a more durable design.

Very common, all 651s are the same. Part has been superceded 4 times. Still a problem.