Time to get some head gasket leak detector fluid?

Broke my cardinal rule on not working on our dailies yesterday and (mostly) fixed the air suspension on my wife's Range Rover. I say "mostly" because there is still a small leak, but at least I know where it is, and it's minor.

However while tracking down the small air leak, I also noticed that my short test drive yesterday seems to have noticeably lowered the coolant level in the expansion tank.

So I took the pressure cap off the expansion tank, start the engine and hey presto! this thing is cooled with Prosecco. Posh, innit?

The bubbles stop when I block off the small flow of coolant which is coming from the hose connected to the top of the radiator.

So do I get one of those "exhaust gas in coolant" detector kits to tell me what I think I already know, or do I save my money?

Can't say I'm humongously surprised, it's always been losing a little coolant even since I had the head gaskets replaced. Initially this was due to a heater core leak, but it kept doing that ever after that was fixed and the shop couldn't find the source of the leak.

Well, talked to some friends in the UK who know their way around Range Rovers of this vintage. Their guess based on the video and misfires is either head gasket or dropped liner. As the head gaskets are fairly new and it never overheated, a slightly dropped liner might be the more likely  issue, but I'm not tearing into the engine to find out. 

Roll that bad boy over to Carmax and sell it before something else breaks.

In reply to slefain :

I guess checking if Carmax takes something that old (2001) with a check engine light that's on might be a good idea.

Have to convince my wife that I can get her something that she'll like as much. Guess I'll better check what her reaction to a Cayenne is.

I'd throw a bottle of the Subaru "Cooling System Conditioner" in there. It's Holts Radweld, which is actually from the U.K., so it should be compatible with the Range Rover.