You may have a clogged heater core so do a heater core flush and unclog it.
Audi tt heater core flush.
Reverse the hose and forward flush again making sure the water coming out is clear.
How to flush the coolant antifreeze in a 2004 audi tt quattro 1 8l 4 cyl.
Now is probably a good time to drain flush and bleed your whole cooling system.
Keep flushing until the water coming out is clear.
Audi tt 2000 06 audi tt quattro 2000 2006 radiator and hose replacement.
Turn on the water flow not too hard as the heater core is a bitch to replace and watch the gunk come out.
Turbo convertible how to video for petcock radiator flush and burping on a 2004 audi tt quattro 1 8l 4 cyl.
Flushing the heater core isn t completely unlike flushing your cooling system during a coolant change except that it focuses exclusively on the heater core itself.
You can use regular water from a garden hose with the caveat that you shouldn t subject the core to a great amount of water pressure as this can damage it.
Here s how to flush it out.