Heater not as hot and blows cold when stopped

[osprey]

I recently had my water pump replaced,the timing belt, tensioner, roller the whole nine yards. At that time I also had the wedge bulb replaced behind the fan.
I have noticed that my heat is not as hot as it used to be even when it is turned to max/4. I do get heat but it doesnt heat up as fast and now have noticed that when I am stopped it blows cool, once I start moving it get warmer.
Any ideas ?
Could it be when the bulb was replaced the connection to the heater got shifted?
Thanks

[speedie]

The bulb change will have no impact on heat level, but coolant not getting into the core will. Sounds like coolant isn't getting into the heater core. Perhaps there is is air stuck in there from the water pump work when they drained the coolant. Keep checking your fluid level in case the air works its way out.

I'm pretty sure you need VAG or another tool to check for air in your system. Call VW or a local mech who knows how to work on VWs and ask.

[osprey]

Thanks for the info, where would the air be stuck? In the heater core? Or the coolant line? I havent a clue!

[hannaco]

Could be either place. You can try "burping" the coolant system. With a COLD motor, just pull out the temperature sensor. If there is any air trapped, it will now escape.
After the car is warmed up, carefully feel the upper and lower radiator hoses. Are both warm, or one warm, and one cold?
Could be a stuck thermostat.