Water temp - an absolute mystery

In the charge to try and get hot air to come out of the heater I have uncovered something very odd.

Last night I drove from work, once the Disco was up to temp on the dash hot air would flow from the heater- Perfecto.

Once home let the Disco idle and only cold air now coming out - WHY oh WHY/

I thought to take off the expansion tank cap to bleed any air out, the water in the expansion tank was cold, althought the Disco had been driven for 20 miles and had been at idle for 10 mins - WHY oh WHY.

Does this sound familiar to anyone, this is my 1st (and could soon be last) Landrover

Thanks in advance for any advise.

thermostat??

I was thinking along those lines too, caould you give me a step by step guide how to change the thermostat?

Thanks

which do you have 200tdi / 300tdi / td5 or v8?

The engine is the 300Tdi on a 1995 ES Disco.

It sounds like your thermo is stuck open as slob has said, when the vehicle is driving the heat generated will give some heat through the heater, but when idling the fan is so effiecient that it will cool the system very quckly hence the cold water in your header tank. there are only 2 x 10mm headed bolts to undo on the thermostat housing and 1 water pipe to remove to give access to the thermostat, there are no gaskets as the thermostat has a rubber seal. Do not forget to top up with anti freeze.

head gasket failure or a major leak, will give a similar reaction but with obvious coolant loss.

sounds like the stat in you case though.

air lock too.