Thread: D2 Over Heating

You might have a bad air lock? Also did you have the heater on fully when you refilled the coolant system?
Also D2s have 4 litre V8s, the Disco1 had 3.9s

Thanks. I'll try a careful look at the air-lock issue.

Also you need to confirm which model you have , D2 is 4ltr and D1 is 3.5 or 3.9 - they have different issues.
Could be the viscous fan clutch.

Try another thermostat if you have one , a new one could be faulty.
When you took the heads off, did you check the block for a slipped liner?

Cheers Mario

Loanrangie, it's definitely a D2, I just slip-up with the 3.9 as I had a D1 before. How do I tell if the fan clutch is not working properly ? I assume if it was faulty it would still rotate but not forcefully enough ?

Mario, I tested the old thermostat on the stove and it opened fine. I only replaced it to cross off an issue, but I'll test the new one on the weekend when I chase your suggestions about air locks etc. I note that the small 6mm return hose from the top of the radiator to the neck of the reserve tank is not flowing as it would normally. Is this a sign of an air-lock or a blockage ? And no I didn't check for a slipped liner but I did look for cracks in the cylinder walls so I hope I would have noticed.

Thanks to you both.

Have you installed the thermostat the right way round? And did you follow the recommended priming sequence to remove air? The heater doesn't need to be on as the coolant circulates through the heater matrix whether on or off.

Originally Posted by Havo

Loanrangie, it's definitely a D2, I just slip-up with the 3.9 as I had a D1 before. How do I tell if the fan clutch is not working properly ? I assume if it was faulty it would still rotate but not forcefully enough ?

Mario, I tested the old thermostat on the stove and it opened fine. I only replaced it to cross off an issue, but I'll test the new one on the weekend when I chase your suggestions about air locks etc. I note that the small 6mm return hose from the top of the radiator to the neck of the reserve tank is not flowing as it would normally. Is this a sign of an air-lock or a blockage ? And no I didn't check for a slipped liner but I did look for cracks in the cylinder walls so I hope I would have noticed.

Thanks to you both.

No worries, you posted in the D1 section so thought something wasnt right.
When hot if you try to stop the fan with a rolled up newspaper you should get confetti, if not then probably not working.
If it looks original it should be knackered by now.

Actually one of the mods move this, why i dont understand - its now in the wrong section .