Smax temperature gauge problem

[emmatimson]

Hi hope someone can help.
Started having problems with increased temperature gauge when doing high speeds.  Had a new radiator fitted last November and also recently had a new thermostat housing, thermostat and seals.

Just done a journey on the motorway with speeds of 75mph and the temperature gauge increased rapidly and the car went into limp mode.

checked the water levels were ok but the water in there was warm? 
Mechanic has advised its not the water pump as the temperature would shoot up immediately.  It seems to be only when doing high speeds.  Could it be an electrical problem?
Many thanks for any ideas.

[Chrispb]

Hello and 
I would say water pump is definitely a possibility, also check if heater is getting hot and can you see coolant returning to the bottle through the return pipe.
Don't want to suggest head gasket failure at this time.

[emmatimson]

Thanks for the info. Mechanic has suggested its not water pump as the temperature would increase straight away.
Im really hoping its not the head gasket.
Thanks

[Chrispb]

We haven't seen many issues with overheating on the MK3's but the MK2's in particular did suffer the problem with the water pump impeller breaking off or spinning on the pump shaft.
Now what your friend has told you is not really correct because you could drive around town all day and the engine would not overheat but take it on the motorway at high speed and watch the temperature go up and eventually boil over.
I Am not telling you it is the pump but it does need to be ruled out.
As I said previously can you see coolant returning to the bottle and does the heater blow hot correctly, if neither of these are happening then I would strongly suggest the pump.