Any suggestion?

[ashj22]

2002 saxo vts, my temp gauge is all over the place the car heats right up to red and the light goes on with in 10 mins of driving then the temp needle starts coming down to half way but the temp light is still on, no smoke at all, no mayo on oil cap either?

[Assenracing]

Might have an airlock in the system

[Chris_O]

As above. First thing I would try is draining coolant, re-filling and bleeding

[ashj22]

could it be the water pump or temp sensor?

[Chris_O]

Could be, could be a partially blocked rad, could be many things. But start with the easiest option which would be trying to clear an air lock

[Prickle]

Do you have a thermostat in out of interest? as chris says start with re-bleeding it and see how it is.

[ashj22]

well i havent checked it has a thermostat, i tried bleeding the rad earlier and thought i had it as the engine temp seemed to stay steady at around halfway, then when i drove 5 mins down the road it heated right up and took like 25 mins just to cool down to half way on the gauge.

[ashj22]

just tried bleeding it for the past 20-30 mins cut half a bottle to use as a funnel used all 3 bleeding points filled it half way up started the car with heaters on full proceeded to fill it up waiting for the bleeding holes to show a steady stream of water with no air bubbles, all seemed fine was idling for like 20 mins and didnt overheat took it for a drive then 3 mins down the road started to heat right up again going into the red?

[Gandi699]

You fill it with the engine off via your funnel thing. Stream of water from each bleed point working to the rear most one.
Then make sure your funnel is at least half full so it's the highest point and switch the car on and let it run until the stat opens and the bottle level drops (you'll see coolant mixing usually and a few bubbles)

Let it cool fully with the funnel in then it's bled.

That's if your cooling system is in working order.
If I were you check out the rad and change the thermostat it's a ten minute job on a vts