Since new radiator, heaters aint got no heat

[Alec]

Had a new radiator and now my blowers dont blow out no hot air, only really noticed it the past couple of weeks as the cold has been setting in. Are these easy to replace and plumb up? Is it possible the system just needs bleeding for them to work again?

[jezza16v]

An air lock is possible but unlikely, firstly check that the pipes to the heater matrix get hot where they pass through the bulkhead.
If they are not getting hot, check whether your car has the VW 'recall' heater bypass unit fitted?
If you have this unit fitted it has probably failed which means you get no heat into the car, there are a few solutions to this problem,
I just sorted mine on Sunday. Let us know what you find.

[nige_s]

Replace the heater bypass valve with a couple of lengths of 22mm copper pipe.  If heating is then restored the valve was faulty, you've then got two options, buy a new valve about a tenner or leave as is for more heat.  I left mine with the copper pipe installed, its a relatively new matrix and I'd rather have heat than anything tepid.  Its been like that for a couple of years now.

[Alec]

Heat exchanger? Wheres that. I am such a vw noob

[jezza16v]

The matrix/heat exchanger is behind the dash, very awkward to get to and tricky to change, that's your last resort before trying everyting else. There are two rubber pipes into it passing through the bulkhead in the engine bay just below the coil, the bypass unit is fitted between the two pipes one bit is metal the other is plastic and there is a very thin rubber hose passing between them.

[Alec]

Cant remember seeing that, I see the two hoses, one is a feed and the other return? One comes out the side of the block or the head doesnt it? I'll go have a proper look in a minute and see what I find

[nige_s]

A bit of searching would help

http://www.golfgtiforum.co.uk/index.php?topic=31666.0

All you need to know, provided your blower motor works and you car has got water in the coolant I'd hazard a guess that this is your problem!

[Alec]

Ah thats brilliant, got my head around it now, cheers nige, told you I was an utter noob 

[nige_s]

Dropping in a bit of copper tubing should take only a few minutes, from memory there is a smaller breather pipe with a 4-5mm internal diameter, just cable tied this out of the way, it won't affect the cooling system as nothing flows through it.

The valve was installed as a recall/factory mod as there was a large batch of bad heater matrix's that burst running at higher temperatures.  The bypass valve just restricts flow to help prevent this, chances are your heater matrix has lasted this long and wasn't part of the bad batch anyway.

[Alec]

Ah I didnt know that, and once I have done this I just run the engine with the lid off the expansion tank for a bit and give the pipes a bit of a squeeze to let the air out?