Matrix Fitted, But No Hot Air

[WhiteMk2Gti]

All the hoses are hot, but not hot air coming out.

Ideas?

(brand new matrix fitted)

[monzablue16v]

Bypass valve might have gone, it's in the engine bay just as the heater hoses go into the bulkhead to the cockpit. Try removing it and use a piece of hose or pipe to join it back together.

[MK4_20VT]

Have you run the engine with expansion cap off? as this allows the trapped air to escape. You also will need to squeeze the top rad hose, to get the air out.

Jay

[Mr Blue]

pull off the 2 hoses that go to the heater matrix in the engine bay.

get a hose pipe and shove it down one of the matrix pipes. Now open the tap and watch all the air escape the matrix.

once all the air is out, the water should flow freely out of the other matrix pipe.

Connect the pipes back. run the engine with the coolant cap off, hot heater blower on.


See if that works

[mattkh]

Hi
Is the matrix bypass hose hot ?

[j_s]

If you've put a new matrix in, you can also get rid of the bypass valves and use copper pipe or get some new rubber hoses.

[WhiteMk2Gti]

ALL hoses (inc those going in and out of the matrix) are hot.

Will try the flushing matrix one as well.

[Lap]

What about the flap on the fresh air box that diverts the air across the matrix when you require hot air? Does it move when you move the cold/hot lever? Check and make sure the cable hasn't come off or something.