This afternoon I went to walk down to see my GP (recovering from Covid) and I noticed a large dark wet patch under the car. It is immediately under the driver's seat (standing on my level drive).

I wasn't sure if it was oil. water or petrol but as there was no smell I assumed it wasn't the latter.

On my return I managed to get down on my hands and knees and it appears to be water. The coolant level is fine and so is the screenwash reservoir. Could it be condensate from the aircon?

I drove about 5 miles this morning with the Climatronic unit in Auto. Seems a lot of water for the condensate a trip like that should generate.

Anyone any ideas where it might have come from?

Probably rainwater out of the longitudinal chassis member under there. It has drain holes which may have been blocked, then not. Or it may have come from higher up, there's an area under the brake fluid reservoir that drains into there, I think. 

Edited 14 March, 20233 yr by Breezy_Pete

Sounds like condensate to me, its pot luck whether it drains during the journey or dumps a lot when you stop, it also depends on the relative humidity, it can be a significant amount and you only need a small amount to create a large patch on an impermeable surface like tarmac.