OK, this thing is starting to get annoying. I am trying to get my disco to run cool at idle. So far I've replaced the thermostat, radiator, hoses, water pump, engine. The old engine had a slipped liner so the cooling system was pressurizing. The new engine is good with new head gaskets but the auxiliary fan keeps turning on at idle, the temp gage never moves from the middle. The next thing to replace is the fan clutch but it seems to be working fine. The fan clutch definitely engages when you rev the engine up. It is freezing outside and my auxiliary fan still turns on at idle. As soon as you rev the engine up to 2K rpm for 20 seconds the fan turns off. In this kind of weather shouldn't you be able to run the truck without any fans? There are no obstructions in front of the radiator, condenser seems to be clean. The upper radiator hose is hot, the lower hose is cold. The hose between the thermostat and the water pump is hot. The thermostat is brand new Genuine Rover. New thermostat didn't change a thing. I just don't get it.

 

i might of missed it..but did you bleed the air out of the coolant system?

 

I probably lost a gallon of coolant bleeding the thing. I've put 80 miles on it so far on a replacement engine so it can't be the air in the system. There is no waterfall sound in the dash.

 

if you really lost a gallon that might be your probably right there..shouldn't lose more than a cup or so bleeding.

 

Dude I am not stupid. I was hoping it was air in the system so I bled it a bunch of times, pretty much every morning before going to work. There is no air in the system. I am going to install an in-line thermostat this weekend and a new fan clutch. The pressure controlled bypass system makes no sense to me so hopefully an old school thermostat in the upper radiator hose will make things better.

 

Yeah Dude he's not stupid...he's almost run out of things to replace!
LOL
________
MarciaSex cam

 

Do you have a scanner hooked up to see the actual coolant temps? The temp "gauge" means nothing except if it goes up over half then you are way overheated. Also the hottest your truck gets is when it is at idle (after it's heated up of course). Let us know the actual temps your truck is running and at what temps the fans kick on.

 

Have you considered it might not be an auxiliary fan that is kicking on, but rather the Secondary Air Injection System? That kicks off and on at idle on it's own all the time....

 

What is the year of the Disco? We don't even know if he has a Disco II.

Anyways my Disco always warms up when running at idle, and the temps gauge stays dead in the middle. And it is not going higher as I drive the truck. Since I already changed the coolant, thermostat, bled the system, and checked that the clutch fan works, I don't worry about it. I simply regularly check the level of coolant in the tank. I'll start to worry when the temp gauge goes up too much.

 

Pretty sure he has an '02 DII