I have a 2003 K74. The vehicle is quite happy to do short journeys ( up to 5 miles) If I pop to Ikea ( 15 miles away) the temperature starts creeping up. Cue heater on full blast!! Recently I checked the top and bottom hose. Top hose was very hot, bottom hose lukewarm. I drained the coolant out in preparation for a descale of the radiator. The coolant that came out didn't look too bad at all. The radiator flush came out clear as well. I have refilled the system and the issue remains. My next plan is to replace the thermostat. Is there anything else I should be looking out for/doing?
My worry is that the water pump has failed. How easy is it to replace that "in situ" ?

never seen a pump fail they nomally start leaking from the wee hole in the shaft as a visual.

I would have changed the stat when u had it drained

check the viscous is working properly

check for bubbles in the over flow/ expansion tank too whilst it is over heating

rad cap could be an idea to change that also

"never seen a pump fail they nomally start leaking from the wee hole in the shaft as a visual."
Thats good to know , as I didn't fancy changing the waterpump!


"I would have changed the stat when u had it drained"
I went for the easiest/cheapest fixes first!

"check the viscous is working properly"
It used to be with a rolled up newspaper, can I do it with a virtual page from the Guardian??

ha ha use the I pad!
get the engine hot then turn the key off the fan should stop dead or half a turn if it spins a full turn or more its too loose.
if your doing the water pump may as well do the cam belt too.