over heating

[Mozza]

So this is a bit of a saga and im fearing the worst but would like to know if i have eliminated all the posible cheep options,

Not to long ago i fitted a new water pump to my aaz as the old on had dry bearings and did not sound healthy,

Straight afterwar my car was now experiancing overheating problems with a strange heater/ blower syndrome,

the temprature will slowly creep up to just below 3/4 at cold tempreatures the blowers blow cold betwenn 1/4 and 1/2 the blowers get warmer and warmer then after 1/2 the start blowing clod again,

the top hose has a masive presure build up, i have ran it with the cap off of the header tank, checked flow of the heater matrix the rad was new when the engine went in to the jetta, i have tried 2 thermostats and i still have the problem, any thing else i can try before i start having to save to het the head and headgasket looked ant and replaced,

cheers for your time ,

Mozza

[arsenicpants]

check for oil in coolant / coolant in oil
this is a surefire way to tell you've got a blown HG

you might have something clogging your water passages, too
try doing a complete flush, twice even
check your rad for leaks, replace it if it's super old

[Mozza]

There is no oil in the coolant. There are no leeks in the rad as this is rather new. And I have tried my best to flush the collage system a few times.

[arb]

Have you flushed it a couple of times ?

Did you use an OEM pump ? Did you check the new pump to see if it was cast correctly, that the impeller is solidly connected to the shaft ? You're not running w/o a thermostat ? Is the bypass hose kinked ?

[Mozza]

Yes I have cleaned out the system a couple of times. The water pump is not genuine but oem. Propellers are fine. I am am running a stat and there are no kinks in any pipes I can see.

[8v-of-fury]

possible burping issue? If there is air bubbles in the head, or trapped behind the thermo.. the thermo will never open (because it does not see hot coolant..) and then the head sensor will see raging coolant temps..

[Smokey Eddy]

The fact that your heater core is not acting normally makes me think the same as Jeremy.
when you fill it up with water drive it with the cap completely off for a while.

[8v-of-fury]

yes let it idle and rev it up a bit maybe short block around the road. Driving it for a while on straight water may be a contradicting issue, if that water starts to boil.. causing even more air pockets in the system when it turns in to a gas

start with no cap, short drive from cold, and then whilst idling in your driveway.. give all the coolant hoses good squeezes to get any air bubbles hopefully circulating..

Also I find it works best to fill from the rad side of the top rad hose ( with it tilted up and sloping down towards the engine ). This will ensure water is getting to the engine side of the thermostat as well..

goodluck 

[Smokey Eddy]

Sorry i always refer to coolant as water. its a bad habit i know. got it from racing at the track in highschool... You're not allowed coolant in the car on the strip.