Incorrectly fitted by-pass valve?

[richandhazel]

Its an absolute PITA
If you're not getting coolant inside the car (leaking matrix) then leave well alone.

Mk1 is a lot easier, undo the 2 pipes and a clipped on cap and out it slides.

[VW2010]

Last night I actually got several seconds of luke warm air, which is an improvement!  I'll try flushing & reverse flushing the matrix this afternoon!

I don't think my matrix is leaking because I don't have to top up the water & wouldn't the carpet be wet inside?

[richandhazel]

Yeah your carpet would be wet and you would notice coolant loss if the leak was substantial enough and yours isn't...........so leave well alone as far as that's concerned

[Blue MK2]

are any of the pipes bent so that the water cannot enter the matrix?

[VW2010]

I've flushed the matrix (just the matrix) & there was two or three seconds of dirty water when I reversed flushed it.  
The heater is blowing warm air now which is a big improvement but its still not as hot as it should be, so I think I'll take vr6's advice & buy some flush & do the whole system!

Thanks to all who've made suggstions, I appreciate it

Ps Blue mk2, all the pipes look ok!

 

[richandhazel]

Something I'm sure you have already tried but just in case, you may have an airlock where its entering the matrix. As the system is building up px try loosening the jubilee clips at any high points especially the heater hoses. I've done that before now and had air coming out for a good 2 mins before it started spitting with coolant.

[91Mk2Driver]

Hey there VW2010,
You just described the same problem that I was having, almost word for word.
I just fitted the by-pass valve and now there is wonderous heat billowing into the car, it's amazing the things you take for granted in a new car!

Anyway, one word of advise. Be carefull when using Rad-Flusher. If somebody who owned your car before you used Rad-Sealer to fix up any water leaks that they might have had, as soon as you use a Rad-Flusher, you run the risk of opening up these old water leaks again.

Take the advice of the other guys who spoke of air-locks in the system, that's what I did and it worked great.

Thanks everyone for all your advice on this (my local VW dealer tried to tell me that I needed a new water pump!!). Brilliant website, keep up the good work.