I am have a 99 Discovery II. Recenly have developed some trouble with heating. Even when the car is warmed up it blows cold air when I am stopped.Once I start moving and keep moving it starts blowinghot air. Then again if I stop at a light it goes back to blowing cold air. Once I start moving and pick up speed it goes back to blowing hot air.

Kind of strange. Can someone help.
Thanks
Andrew.

 

Andrew,
Your truck is running very low on coolant. I would suggest you top off the coolant bottle and have some do a pressure test on the coolant system to find the leak. You want to rull out head gaskets as soon as possible. If you are lucky, it may only be some external coolant leak.
Make sure you only use Dexcool coolant in your engine.
Mike

 

Also open up the hood and look for evidence of a coolant leak on the drivers side valve cover (orange color staining)--towards the back of the cover. This will indicate the throttle body heater plate is leaking, and must be corrected NOW. When you start it in the morning, does the inside of the windshield fog up at all?

regards,
Geoman

 

I have the same thing happening to me. No, the windshield does not fog up. I replaced the heater plate gasket, and thought I fixed the problem, but continued to smell coolant. I noticed that I was getting some indications that it was leaking by the small amount of coolant on the floor. It seems to be coming from the front passenger corner of the vehicle. Any ideas?

 

find where the coolant is leaking from. You say it is leaking inside the truck?