Water pump gone?

[Brabus3.6]

As of late I've had some intermittent water loss from my m103 brabus. In a couple of Oxford-London-Oxford runs (about 130 miles) no water can be seen to be lost while in some others about 3/4 (75%) of a liter has gone missing.
The car hasn't been used for a couple of weeks but last night I put it up on axle stands and removed the engine tray. Immediately apparent was greenish coolant (I assume!) on the a/c compressor. I wiped off the liquid, ran the car for 20 minutes or so but saw nothing. I then removed the belt pulley from the water pump so that I could feel the weep hole but it was dry. However, I understand that sometimes it is the shaft which leaks only when revolving.
I know that a/c causes condensation elsewhere in the system on vehicles but surely the a/c compressor would never get cold enough for this as it's bolted to the engine?! New water pump, or look elsewhere guys???

 

[grober]

Cylinder head gasket on the way out?? Does it misfire momentarily on starting from cold? Has one of the plugs have a wet look? Your local specialist will have a device which can detect exhaust fumes in the coolant. I,m not saying its this just a possibility?

 

[andy_k]

we've got a water pump just like that on our W123. It leaks mainly when the car is left to stand. When it's running it loses virtually no water

It's been like that for 6 months now and never seems to get any worse but it is booked in at the garage to get it done in a couple of weeks

Andy

 

[Brabus3.6]

Grober I pray it's not the head gasket again. It's only about 10,000 miles old and is upwards of £400, the guides and stem seals have been done so it really would just be the damn gasket.
It has KE related injection issues as it has a hesitation up until 2000 RPM or so which goes when the CTS (and has KE-jetronic system) is disconnected. I believe the misfire is related to this.
Could just be the o-ring between the pump and block perhaps, but it's a lot of work just to change that!

 

[Dieselman]

Waft an emissions tester over the expansion tank filler with the cap off. That should detect any combustion gasses in the water.