Discovery Over Heating Issues

[Rover Rob]

I have a 1999 Land Rover Discovery 1 SD and having over heating issues. I can drive it all around the neighborhood and it doesn't over heat. If I drive it 40MPH + for 1 mile or 2 it will pig the needle.

I installed a new thermostat but no luck. Water is circulating through the radiator. The clutch fan is operating, 1 out of the 2 small fans that are mounted on the front of the radiator is not running. Could that be my problem?

 

[joey]

How many miles on the Rover? Overheating could be a few things. Blown Head gasket, water pump not doing its job, radiator partially clogged. The A/C fans (front of the radiator) should come on if it starts to get hot or the A/C is turned on. One of the two not working will not help, but they shouldn't be needed when you first start driving.

You could also have an air bubble in the system.

 

[Rover Rob]

New water pump, you follow up is very helpful. Air bubble? How do I get the air bubble moving or out of the system.

 

[joey]

Air bubble if you have one - easy way is to park on an upward incline so the front of the rover is at least about a foot higher than the rear. Open the fill tank for the coolant system (please make sure it isn't hot). Turn the heater on when you start the rover and slowly fill until it doesn't take any more antifreeze mixture. After about 5 minutes of running, shut it down and let it cool off a bit, start over again. Do this till it doesn't take any more fluid. Usually 4-5 times.

 

[jr266]

clean the radiator