The heater in the 2001 Discovery 2 is not working. It blows fine but never does get hot. Any suggestions

 

Probably need to bleed your cooling system.

 

Clogged heater core? I have had luck disconnecting the two hoses going to the firewall and running water through it backwards to flush out gunk. Beware that this could cause a leak to start if it's too late. I've never had a leak start but I know some who have. I use a garden hose for this.

 

no heat could be related to coolant issues. Every time I've done a coolant flush I've lost heat for the first bit until the system clears air etc.
How are our coolant levels?