Cooler air at idle

[vwgtiking]

When I have the heaters on hi and engine warmed to 90 they blow really hot air which is fine, but soon as I stop in traffic or at lights the heater blows cool air or barely warm. What's causing this?

 

[stu_m]

its probably the cold winter air causing it!!

I'm guessing its a TDI? they run cooler and cool down quicker

 

[S4_dan]

Weak thermostat, air in the system, weak water pump, or just generally cold outside.....

Try placing a piece of cardboard in front of the radiator and see if that makes any difference.....BUT KEEP AN EYE ON YOUR TEMP GAUGE IF YOU DO THIS.

 

[vwgtiking]

It's a 1.8t. Why would cold affect it? Engine hot then hot air? Never had issue with mk4 golf 1.8t.

How easy is it to change thermostat on these b6s?

 

[vwgtiking]

Water pump done recently.