Heater refuses to blow hot!

Hi

Whatever I seem to do I can't get warm air into the car.

Plenty of coolant in the system, Changed the heater valve already so I know it's not that, any ideas what else I can try?

Starting to think a air (or an actual blockage) in the heater matrix but any others would be great!

Tried running the engine with the cap off but this doesn't seem to have sorted it…

Thanks
Adam

Do the hoses get hot going to the heater?
You can see the hoses in the engine bay going into the bulkhead, inlet and outlet.

They get warm (but not as warm as the radiator pipes) - possibly getting warm from ambient heat maybe?

try manually opening the valve in the bay so you know its fully open. the matrix might be blocked?

the system should self bleed, but this bleeding method never fails me:
http://clubgti.com/showthread.php?145091

low temp thermostat installed.
heater valve that is maladjusted, not fully opening.
The valve arm isn't against the stop.
Broken heater valve internally.

Clogged  heater core (matrix).

You can use hose pinch pliers an clamp off the heater hoses.

Disconnect them from the Valve, and the butt-to-butt connector on the lower (best to replace that with a barbbed brass hose or steel connector if yours is plastic.

at the upper hose, fill it with 1/4 cup of CLR (Calcium Lime Rust) remover,,,, Strong vinegar works let it work for about 20 minutes.

Take a Garden hose, and flush it from the top to it exiting the bottom hose till it runs clear.
Reverse the hose and flush  it from the bottom to the top.

Repeat the flush top flush bottom about 4-5 times till water runs clear….

Reconnect the hoses and top off coolant, you should be good to go….

The original matrix will burn your butt out of the car.

The A/C units are a tad harder to replace than the non-a/c units….and if yours isn't a a/c unit.  I would think on removing it to flush and back flush..

In the Archive section I have a link in my how-to's on beefing up the heater valves…