GTI 16V Slowly Overheating

[jimojameso]

Hi guys

I have a GTI 16V. All was running well until one day on the motoway my golf started overheating.

I have changed the water pump, thermostat, radiator, most of the rubber pipes and the expansion tank cap. The car doesnt seem to overheat now apart from on idle. The water temp gauge is bang in the middle and the oil temp is on 124. Before i had the overheating problems the oil temp would be lower around 106-110. Now the oil temp is higher and on idle the water and oil temp's start to slowly rise again 

Anyone got any ideas? Dont think there is any blockages or air locks anywhere in the system. Im sure of it. Please help.

Thanks

James

[boxer1968]

have you heard the fan cutting in? you say no air locks pipes all hot?

[jimojameso]

Yeah fan kicking in and all pipes hot

[raferackstraw]

have you changed oil? if not do so and new filter. 124 is a bit hot mine never goes above 110. could possibly be the oil temp sender has gone duff or is reading high. if your sure coolant system is function properly, it maybe worth taking the sump off and checking the oil pick up and the oil pump. the other thing to check is the oil/water cooler on top of the filter, although if that was duff oil would be mixing with coolant.
did you bleed system as per coolant faq

[clipperjay]

I've always run holts water cleaner before doing anything major just incase there is sludge later on to created blockages and such. It might be worth when cold to start her up and keep pressing the main water pipe until the expansion tank just starts to get toi boil temps then wack the cap on quick before anymore air goes in?
 

[rob.043]

Can mixing 'blue' and 'pink' coolant types cause sludge build up? Im not really sure of the different specs/details, but heard it suggested somewhere....

Perhaps when you last refilled the system the new coolant was a different type?

I do know that its reccomended to have at least 50% water in the mix, as its what moves the heat from the engine to the rad. Deffinately got enough water?

[Ben Lessani]

Have you checked your fan + fan switch ...

Mixing coolant shouldn't be a big deal, although it isn't recommended. On the same note, coolant % mix isn't really a big deal for heat transfer, it is purely to stop corrosion and freezing.

I'd do as above, change your oil/filter with semi-syn 10W/40 and flush your water system with a hose (remember to remove the thermostat first) then refill with G12.

Failing the above, just drive faster to your destination before it heats up too much 

[clipperjay]

If you dont fix this the best alternative is to find a low temp fan switch proberly from a TDI unit so fans kicks in bit earlier to help cooling down side the fan will be worn out quicker but rather a new fan than new head?
Ps fan is at correct RPM? & no bearing sounds from the fan motor?
The flush would be best best the issues over the years have always come from heater matrix as the channels are smaller the blockages tend to be in there! Try running the heat at max when bleeding the whole system, but the way it took me two hours once to get all the air out by pumping the main rad pipe 

[jimojameso]

Thanks for all the help guys. All sorted now thank god 

[Ben Lessani]

Thanks for all the help guys. All sorted now thank god 

No clue as to what the solution was ...