Blowing Hot Then Cold

I have a 1989 mk2 Golf Gti. Recently she has started blowing hot air form the heater which lasts about 5 minutes max then starts blowing cold air. Any ideas whats causing this would be appreciated as its begining to get bloody cold

Thanks

Marko

 

There is a heater bypass valve that is the cause of your problem.

If the heater matrix split, then scalding hot water would flood all over the front floorpan. To stop them getting sued, VW fitted a bypass valve that stopped this happening. Unfortunatley they are now wearing out and the symptoms are exactly what you described.

A new valve is not very expensive, and fits between the hoses just inside the engine bay - so it's not a big job to fit.

Simon.

 

Will try this weekend thanks alot

 

Have fitted and is working ok.

Once again thanks alot

 

Nice One mate. What did you give for the valve?

 

27 QUID FROM SPIRIT MOTORS IN BANBURY

 

where is this valve, what does it look like, how big is it, what is involved to change it etc etc..

 

Its silver its on the matrix supply pipe and has a pipe out of the valve going to a black valve on the return pipe for bypassing the matrix, its on the nearside back of the engine bay firewall near the coolant bottle

 

Both can stick, the silver or the black one. My advise is whip the f**kers out and put straight through pipes back in.