has it been raining
No, and it's been sitting there for about 2 days.
Couldn't be without my Commodore
Actually looks like the mark left after a battery has been washed down. Could be coolant though.
Certainly looks like coolant because it has stained the concrete and just because it is at the back of the engine does not mean much, I had a VP water pump leak and run along the sump then drip off the rear.
Are you losing coolant, have a good look around your engine and see what you can see.
It is a coolant leak, i would check out the hoses that ran from your heater tap to where they attach to the firewall it may be split, hence the fluid at the back of the engine.. I had this same problem
If the heater hose quick connectors leak it can run down the exhaust and the back of the engine.
Silver Certified.
hmm A/C fluid ?
if it is the concreet is quite white in center then goes to that brown coullor then back to normal?
Has it got steel welsh plugs? Often rust and leak, prob not, but often overlooked, though not sure of your engine.
It's coolant. You can tell by the watery look but with the slightly dirty mark, prob a little oil or some contaminants. If you want to be sure stick your head down there, if it smells kinda sweet then it's coolant. It's not oil, and if it were water/condensation from the air con it would have dried straight up. It's coolant.