Golf MK2 Overheating

[Dudd]

Hi all.

I’m having some issues with keeping the temperature low. I thought it might be the water pump so I have replaced this. While I was there I replaced the thermostat and all 3 belts. I have also replaced the reservoir, reservoir cap and all the cooling pipes (everything except the radiator really!). Still no luck.

I’ll top up the water and dive the car for 30ish minutes and either the buzzer and high temperature light comes on or the low water level flashes. I’ll open the bonnet and there will be steam coming out of the top of the reservoir. There is no mayo in the oil so I don’t think is the Head gasket.

My thoughts say is the cap broken (already) and the system won’t keep pressure and leaking out the top? Or is the system getting too hot the pressure too high and the valve in the cap releasing?

I’m so confused. Can anyone help?

[Dr G]

Checked for airlocks? Tis a bugger to get a MK2 system bled properly, run it from cold with the cap off and heater on full blast hot. Keep squidging the bottom hose until the header tank stops bubbling.

[Dudd]

Dr G said:

Checked for airlocks? Tis a bugger to get a MK2 system bled properly, run it from cold with the cap off and heater on full blast hot. Keep squidging the bottom hose until the header tank stops bubbling.

Yeah I think i have removed most airlocks, but each time I drive it it has lost coolant from the expansion tank.

[paultownsend]

buzzer is low oil pressure my friend. did you completely flush through the system with a hose? block and rad?

[paultownsend]

oh, and are all parts genuine? the cap must be. id get genuine reservoir too. use G12++ from dealers only

id check compression to be on the safe side. never underestimate what symptoms a h/g failure can give.

mine was a terror on the 16v

[aka_kerrly]

As has been mentioned, the buzzer is LOW oil pressure - NOT good. This could be a dodgy sender or it could be your oil pump is on its way out and perhaps the pick up pipe in the sump in blocked.

If the coolant is being forced out of the expansion bottle it could be a duff lid or bottle. I realise you have new ones but in my experience some of the new blue expansion lids are crap as are the bottles. I replaced mine with items from GSF and was still finding the coolant getting blown out the lid. Bought a genuine VW expansion bottle (mk4 golf variety was £15 from dealers!)and its been fine for 15k now.

what happens if you run the engine from cold without the expansion bottle lid on.... what should happen is the engine will do a cycle, the fan cuts in, coolant temp should be half to 3/4 on the temp scale before dropping 1/4 after the fan has cut off. You should find after a cycle any coolant that was going to overflow will have been forced from the bottle. If you then allow the engine to cool (1-2hr) then you can refill the coolant back up to the MAX mark and put the lid on - tight!

Dave

[Dudd]

paultownsend said:

oh, and are all parts genuine? the cap must be. id get genuine reservoir too. use G12++ from dealers only

Its always the simplest thing. The o-ring in the reservoir cap wasn't seated so it was leaking water and not getting pressure.

I feel like a right tool now for not checking it sooner...

Thanks though guys!

[Sideways Rich]

Hi folks, I had the same exact issue with a mk 4 tdi golf yesterday. Any other items to check other than those mentioned above?