hi all had the RR 4.2 about a month now and the temp gauge still sits at 10.00 when driving, also heater does not get boiling hot . dropped the mrs off in tesco,s and sat in the car park with engine running for 30mins and it got to 12.00 on the temp gauge and stayed there . mrs jumped in the car drove off after about 5mins back to 10.00 ? sounds like thermostat? also when I lift the bonnet fan seems to be running all the time.

Most likely thermostat shot or stuck open. IIRC on the petrol it is an easy access job on top of the engine at the front. Plenty on here about this, and RSW Solutions has done a video on changing out the 'stat. .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Yep sounds like thermostat and is exactly the same problem I have on the supercharged 4.2 I have just bought. I have got a genuine thermostat and seal from Duckworths, think it was about £25, and I'm going to change it this weekend. Looks like an easy job, positioned front of engine kindof above the water pump.

just changed thermostat and all is well sits at 12.00 and heater is up to full heat! easy job to do

also atlantic british do some great video,s

 .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999