Poor Heating inside the car 1990 Golf GTI 16V

[Garrydohc]

I have owned my trusted mk2 gti 16v for 3 years now but it has now developed an interesting fault.  The heating levels in the car are rubbish and even with the heat control on max it seems colder inside the car.  The car has a thermostat fitted and the head gasket is ok. Could it be possible that the thermostat itself is knackered? The engine temp reads ok and the car itself runs ok. Any Ideas? All help appreciated. Thanks.

[mattneck(Beavis)]

search search and search again as many people say this comes up all the time, i admit i did ask though, search for heater bypass valves, theres a post in the mk2 maintenance section 

p.s. welcome to the board! 

[DarnPB]

It could be your thermostat. To check it, remove it and put it in cold water and it should be tightly closed. Remove the water then add boiling kettle water until submerged and it should open.
If it is open all the time (Hot and cold) it should be replaced. If it is ok, refit it and look for problems with the heater bypass valve, or the heater matrix itself. That could be blocked.

[durst805]

I had this problem with my 89 GTi, there's two valves in line with the pipes that lead to the heater matrix, (look in the Haynes manual), they're there to stop overheating. But when they get old they tend to stick, all I did was take them out and replace with lengths of copper pipe and jubilee clips, problem solved.

[Gambit]

aye 1st step is cut out the bypass valves they are a waste of time

[Breaker]

has anyone checked out the brain section in this months golf+
it says that fitting a bypass is bad without changing to a late mk3 heater matrix
as the valves were fitted to stop the matrix exploding in the event of cooling system/engine malfunction

basicly if something goes wrong a the pressure rises without the valves the matrix can burst!

[Dizzie]

I replaced my heater matrix last week and it's like an inferno now

before there was a smallest bit of heat coming from the heaters and if I put the fans on it would quickly go cold again.

a matrix is only £30 from GFS, but you'll need to remove the dash to replace it. apparently you can do it without taking the dash out, but I always find it stuck to the bulkhead so requires a good pull to free it!

you can tell if your thermostat is working because the lower rad hose will be cold when it's shut (obviously before you've ran the car for a while). when it opens the fan will come on and the hose be warm

my money is on your matrix has gone and needs replacing

[Topuz]

I have a problem with heating too, but I think mine is bigger  .

First of, on the heating conrol panel, on the 1-2-something-3 switch, 1,2 and 3 positions have exactly the same effect. The air passes trough, but that's it, it only passes, not quicker than when I walk on foot . What should be the difference between these 3 positions?
Next, when i select windscreen air symbol on the switch, I can hear the fan blowing, and the air is blowing nicely, but It's quite cold air, barely heated.

What do you guys think?

[rubjonny]

problem 1 = buggered fan resistor, or perhaps the fan itself.  Problem 2 = buggered bypass valves, or perhaps matrix.  may even be a problem with the heater flaps