I took off the left head and there is obvious head gasket failure between the rear cylinder and the the coolant channel.

 

Well then, case closed. Good luck.

 

Right head was worse in the same spot, original rover gaskets, when I was loosening the head bolts, #10 bold was loose on both sides compared to the rest. The right side lower bank of bolts were much easier to break loose than the upper bank, a curious thing. I must say this is one of the easier head gaskets to replace. Above it was mentioned to pressure wash the heater core and radiator, why not just run water through with a hose, wont pressure destroy it?

 

IHSCOUTS, its a 2000 DII.

 

Try the hose through the core and rad but it's also in the block. A Rover is a Rover to me, I've replaced head gaskets on em all except a Series. DIi's take twice as long because of the crap bolted to em, the only big difference.

 

One other thing, if your power steering pump is whinning now is a GOOD time to replace the gaskets/seals.