3.9 v8 running hot

Hi , not long bought my disco 3.9v8. having a strange overheating problem with it. my temperature gauge is up at 3 quarters , and on a long incline even slightly above - very concerning. it does sometimes run cooler - when the heater is on - it comes back down to just above half. no coolant loss i can find , runs fine and no steam or over presurisation

any ideas , should it be concerning me? oh and problem is the same on petrol or gas

thanks , ryan

Viscous fan coupling?

totaly agree viscos fan coupling replace with a kenlow fan and save a little money on fuel no that is cr*p its a v8 rev it an smile happy days

Sounds as though you either have a sluggish thermostat or a partially blocked radiator or both.

If the extra cooling capacity added by turning on the heater improves matters, then your total cooling capacity is insufficient. Try the thermostat first, that's the cheapest thing, then while you are there, have a look at the radiator core and see if it is bunged up.

Coolant should be 50/50 mix of OAT spec antifreeze.

The problem with electric fans is that they block the radiator airflow when not working. Check the existing coupling by trying to rotate the fan while the engine is stopped. It should turn with some pressure on the blades, it should NOT spin freely. Mine will spin for 1/4 to 1/3 turn if I try and spin it by hand.

Peter

If you fit an electric fan then fit it to suck just like the standard fan, you will have to if you have air con as you will have two fans in front of the rad, which don't cause any problems.
The trouble with electric fans is the fans thermostat has to be a degree or two higher then the engines normal running temp, obvious really otherwise the fan would be running all the time, I think the V8 gets hot enough with adding to it.

I run a Kenlow on a 2 ltr four cylinder car without any problems, it's a blower and air passes through it as it 'free wheels' spins without power when the vehicles moving forward and I get five extra BHP's .