Odd that the coolant is a different colour in the expansion tank? I'd guess that someone has drained the coolant from the motor/rad and refilled it with a green brand, but didn't tip out the old pink coolant from the expansion tank. The expansion tank won't drain via the water pump's drain bolt, it has to be pumped or tipped out.

Even if that's the case, you'd expect (as the coolant expands and contracts into and out of the expansion tank) the two colours to get mixed up over time?

You haven't got a kink/blockage in the hose that connects the rad to the expansion tank?

I have a Trailtech TTO temperature gauge fitted, ( http://www.trailtechproducts.co.uk/a...mperature.html 19mm ID) mainly because I have a mistrust of warning lights. Generally when they come on it's too late; you've overheated. A temp gauge let's you know what going on in real time and gives advanced warning if trouble. Plus you can see when the thermostat opens and closes, as well as the exact temperature the fan cuts in on the move.

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