this has probably been asked before but i cant seem to find anything maybe just me but anyway i have a mk4 golf tdi 110 and it is blowing out cold air when its at proper running temp ( needle sitting at 90 degrees) ive flushed the whole cooling system all seems fine checked the thermostat by putting it in a pan of boiling water, its not pressurising at all so shouldnt be head gasket, so would i be right in guessing it would be the water pump?
had the same issue on my wifes car (not a VAG) turned out was the water pump, you can see if there is coolant flow going back to the expansion tank, if nothing then most likely is the pump, before you start ripping things apart though, are the heated hoses that go through the bulkhead getting hot? if there are hot to touch once the car has reached 90 then it might be something on the heater box itself.
water pump then, no flow unless the matrix or pipes have a blockage, take the heater hoses off and put a garden hose in one, if it flows out the other one then the matrix is fine and its 99% the water pump
no worries, when i was testing mine i could take the heater hoses off whilst the car was running - sure sign it had no flow right there
have a look in the flange on the side of the head, if it has the 3 glowplug things in it thats the coolant pre-heater setup which may have failed. ours has it but its the PD150 with all the toys on it, not sure if the lower spec used it too
found the culprit was the water pump came out in two parts but now i have no power as if the turbo isnt there also sounds louder then it was/should be checked all the vac hoses all ok crank and cam timing are spot on could it be the fuel pump timing out if so how do i sort it?
