Thermostat??? Heater bypass??? Matrix???

[HuwMk2]

Hi all. Fed up of icy interior glass and poor heater in this cold period. My golf is suffering from the following issues:

1. The temp gauge doesn't normally rise to even the first bar.
2. The heater blows luke warm on setting 1 but gets colder when turned up to 2 and stone cold on setting 3.

What do you reckon? Thermostat? Dodgy heater bypass valve? Matrix? Anything else?

Cheers.

[Alec]

Same problems as you, people have suggested thermostat (official from VW) and copper pipe in place of the bypass valve for the heater (unless you can find a new one)

[HuwMk2]

Same problems as you, people have suggested thermostat (official from VW) and copper pipe in place of the bypass valve for the heater (unless you can find a new one)

Got the copper pipe ready to replace the bypass. I'll let you know how I get on! Will order a genuine VW thermostat.

[rubjonny]

have a read of the cooling faq before you do anything else

[AudiA8Quattro]

Change the thermostat 

[HuwMk2]

Cant swap the heater bypass for copper pipe as intended - its never been fitted with a bypass! lol

Ordered a thermostat and housing from VW to collect on Sat. Fingers crossed this is the problem?!

[tony_ack]

Ordered a thermostat and housing from VW to collect on Sat. Fingers crossed this is the problem?!

Probably is, but I wouldn't rule out a bust matrix. Check under the carpets and soundproofing in the passenger footwell - if the soundproofing is soggy and smelly, it's time for a new matrix. Ice on the interior glass in winter usually indicates some dampness in the cabin, but it could just be some snow that you dragged into the car with you or leaky doors.

[sammymk2]

hi, similar problem with mine, heaters working fine untill full operating tempiture then start to blow cold, changed the thermostat recently, whats this about the heater bypass do you just repace it with a copper pipe? I havent got around to checking the matrix yet.
 

[HuwMk2]

Yes, two lengths of 22mm copper pipe, about 4" each.

[TreadGingerly]

I have this problem... Matrix isn't blown..Thermostat replaced in summer.. Shut off valves done away with at the same time.. Reasonable heat in warmer weather but virtually non existent now.. Could the matrix block up? Limescale or general crap? Air block? Has anyone ever tried taking the pipes off and sticking a hose into it to flush it out? Another cold GTi driver...