1994 8v gti heating problem

[laytonsharp]

i have changed the water pump, radiator, stat and heater matrix. all pipes are warm so i know that the coolant is working its way round the system but i only get mild warm heat in the cabin. any help would be great thankyou.

[itavaltalainen]

Pump is running the right way around?

Otherwise could be that the flap is jammed or that the insulation on it (foam) has fallen off and it lefts too much cold air in.

[gasketface]

airlock

[itavaltalainen]

I have never never never ever had an airlock on any of my mk3s..... but I always massaged bottom radiator hose when filling with coolant.

[gasketface]

you are lucky then as iv'e always had to bleed it once its been drained.Airlock occurs in heater matrix usually.

some people forget to refill it on level ground though.

[itavaltalainen]

The other trick is to fill up expansion tank, then replace cap, then run engine and knead the rad hose....
With that you'll never get an airlock. Remove cap carefully in between topping up.

[gasketface]

For an 8v or 16v the way to bleed an empty sytem is to take off the thin return pipe that goes to the expansion tank.Hold the end as high as poss with engine running.

Fill VERY slowly (pint a minute) and wait for all the bubbles to come out of it (along with some water),engine still running.

Reattach once bubbles stop.Fill system to lower level and run car for a few miles until it reaches normal temperature.

Let it stand until cool (2 hours or so usually) and then check level/top up.

All on level ground on a cold engine.