Latest. This morning I filled up the system and it started coming out from the bottom of the system almost immediately, without starting the engine. It's not the radiator, it's further back. It's not the water pump. I'm pretty certain it's not the thermostat. Although after taking what I could off the top of the engine I still couldn't get my manly hands in there to feel if it was wet. It's coming out from around the heat shield on the front of the engine. Anyway, I'm gonna try and get it to my jag guy today.

Watch this space.

 

If its loosing water that fast, you better tow it in.

 

There is nothing inside of the front engine heat shield except the head gasket, but broken head gasket can not leaking fluid that quick? may be it leaked from two hoses next to the oil filter? You need a bright flash light.

 

Since you're losing coolant rapidly, it's a cracked hose, radiator or overflow tank. You need to get front of car up on jack stands, remove the splash shield and have a gander. Get yourself a good flashlight and eye protection. Coolant leaks are a common problem to any car - take your time and find out where the leak is. Once you find out where the leak's from you can put together the part(s) needed. Since you've got a major leak plan on replacing all the coolant with fresh.