No hot air

[golfmk4owner]

Hi guys, i have no hot air coming from my vents. Ive changed the thermostat, no joy.
I read something about taking off the heater bypass valves because they can cause this problem, but if they were the problem would those two pipes still be hot? The pipes are hot so it makes me think its the matrix... but when i discconected the pipes at the bulkhead and blew through them there didnt seem to be any blockage...
Getting annoyed now and its freezing!
1991 GTi 16v

cheers

[lemski]

Mines was like this. I took the bypass valves out and now there warm, but occasionally go cold so am off thermostat next.
Cheers liam

[dan_apps]

wet footwells too?....

[golfmk4owner]

Wet footwells? no, why would there be? Just no heat!
Bad weather for no heat lol!

[lemski]

Wet footwells means heater matrix is leaking. Water won't pass through to heat air then. Most people upgrade to the mk3 matrix as there better. Just getting round to doing it. Probally the best bet, then u can get rid of the bypass valves as mk3s didn't have them. It was only as mk2 matrixes liked to explode.
Liam

[golfmk4owner]

Ah exploding hot water, doesnt sound great.
Nope no leaking, just no heat... but like i said, the pipes are hot at the bulkhead... any ideas?
I dont suppose its possible that the matrix is hot but the hot air isnt being diverted to the vents?

[mwep201081]

heater box could be nacked. its a piece of metal with holes in covered in thin foam.....

The foam deteriorates and you get cold air instead of hot....

Have you ever had of foam come out of your blower?

[weazgti]

Also i found with mine the outer cable had come off a clip so the inner cable wasnt opening the flap.
Try moving the flaps by pushing the arms on the heater box and see if that helps.

[X4MGS]

I would remove the bypass Valves and also check the water pump etc..

Have a read of RJ's cooling/heating check thread in the maint & Info section..