[jstuckey]

Hello and thank you in advance.

So I just bought a 99 Land Rover Discovery II that is in great shape with the exception to an overheating problem the last owner just started having and its my problem now. This is what I have noticed. In idle it will sit for hours and not overheat, but when you take off the gauge temp shoots through the roof. I just bought this and have not driven much. I have an infrared thermometer I'm going to use my next day off, where would be the best place to aim it I guess? I would think the upper radiator hose or radiator itself? Anyways, it overheats when driving, I pulled over when it started nearing the top of the gauge. I got out lifted the hood and it did not look, smell, or feel like it was overheating. It cooled down and I got it parked at a friends house. There is no anti-freeze loss. I'm thinking that the thermostat needs changed, or possibly a coolant reservoir cap needs changed I'm just not sure so any help is appreciated.

 

[MRussell]

Check the heater core lines at the top of the engine going into the firewall. You might have to take both of them off and flush it back and forth with a fair amount of pressure. Also check each leg of the thermostat to see if there is flow. Your temp sensor is on top of your lower intake. If you can find a know good one and swap them and test.


Mike Russell
Age 18
2003 discovery se
Lover of Rovers

 

[jstuckey]

Ok so how do you flush the heater core? The sensor is a Coolant Temp sensor, correct? On the thermostat can you just run water through each leg of it or what?

 

[MRussell]

With the heater core, you want to to make sure it's not filled with coolant that is breaking down. Run water though both hoses back and forth. The sensor is what tells the water temp. You could test it by having boiled water and dipping the sensor in it and seeing if you gauge response is what it needs to be. As for you thermostat, it could be stuff closed or only opening a little. It would cold fine when not under load but when you get going it can't handle it.


Mike Russell
Age 18
2003 discovery se
Lover of Rovers

 

[nelson845]

When cold move the main fan by hand. You should feel some resistance and it should not move more than a quarter turn when you push on it. Your auxiliary fan should come on at 210 degrees(+/-). When the stock guage goes past half way your temp is way past 240 degrees. Get a scan guage or similar to read actual temps. Good luck.

 

[redrover99DII]

also check your clutch fan , if it is free spinning its done if it has slight resistants then its still good .....but from how you talking i would look hard at the clutch fan