Mk4 1.8t gti heating up

[Toby hawken]

Hi I'm new to this forum and only recently brought my first golf it's 1999 1.8t gti all stock.

Has only yesterday starting to get hot. Done radiator flush and replaced coolant. Sits on 90degrees on idle for ages won't move thermo fans cut in and out like normal. As soon as you drive it then heats up gets to 120degrees plus. and the warning light comes on. Then as soon as I pull over the temp goes straight back to 90. There are no traces of water in the oil and not blowing water out the exhaust nor is it loosing coolant.
It also has started misfiring. Which goes away and comes back.
Any ideas of what the issue would be
Thanks

[Carl!]

Good chance its the water pump, the original one has plastic impellers which are prone to failing so it stops pushing coolant round. It recently happened to me.

[barrym381]

Good chance its the water pump, the original one has plastic impellers which are prone to failing so it stops pushing coolant round. It recently happened to me.

+1 on it being your waterpump 

[Wazzzer]

yep get your water pump checked out. Sounds like it's partially failing at the mo but get it sorted before it completely fails. Are you getting water flowing back to your header tank via the small top hose?

[barrym381]

yep get your water pump checked out. Sounds like it's partially failing at the mo but get it sorted before it completely fails. Are you getting water flowing back to your header tank via the small top hose?

we had some water return to coolant tank even though the pump was broke it still pushed some water through the system  just not enough

[Screech16v]

Remove the thermostat and feel the pump impellor to the left it could be broken or if you can turn it then it will be slipping on the shaft,but it may only slip when hot.