I have a 2008 Defender 110 TDCi (Puma) with air conditioning. Recently, an engine coolant leak has appeared at the rear of the engine compartment beneath the vicinity of the heater core in the dash. It only occurs when the air conditioning is turned on. I would expect that an engine coolant leak from the heater core would occur when the heater is turned on and not the air conditioner. So it is a bit counter intuitive. The fluid leak source is above the transmission so I cannot actually see where it is coming from. It is NOT coming from the coolant reservoir (expansion tank) and it is not simply condensation, it is an engine coolant leak. I recently had the clutch slave cylinder replaced which required dropping the transmission so I expect the problem is related to this extensive work and something was damaged or not reassembled properly. Any experience with this and advice would be appreciated.