No Heat but lots of AC...HELP

[blackhat840]

Hey guys,

I am loving my X5, but I got up this morning and it was 49 degrees F outside so I thought I would warm up the X just a little bit before jumping in. I let the truck run for 20-30 minutes with the heat on, come and get in the car and the air blowing from the vents is still cold. I thought maybe it just needed to warm up a little longer so I start driving to work. Well, by the time I get to work the vents are still blowing cold air!! The temp guage in the car ALWAYS stays dead center after the car has started and the AC in the car works wonders. Do you guys think it could be my thermostat? I also have a weird knocking sound that comes and goes from the driver side of the engine normally near the driver front tire, BMW tech told me its probably the mechanical water pump??? Any help would be appreciated!