Losing water from expansion tank

[G20RG B]

Hi, looking for some help,

I recently filled up the expansion tank with some water as it was looking low, but after a spirited drive when I came to stop at set of traffic lights the water all bubbled up and came spewing out the expansion tank... I waited about 30mins at the side of the road then started the car again but the temperature gauge went to 100 after about a minute so I stopped and shut down the engine.
I filled it up with water it took about 2 litres...and I got home.(this was last Saturday)

Today the exact same thing has happened again. It's the first time I have used the car since last week.
Should I just be putting water in or should I mix with some coolant ??

Can anybody suggest anything that would help me sort this problem.

Thanks in Advance (ohh.. 2003 Cerbera)

George.

[BGB autosport]

Deffinately coolant, not just water, it will corrode the water ways otherwise. Are the fans kicking in?

[kevin63]

Check your radiator, mine had a slight leak but did not show up as the water just evaperated. Take the pannels off around the rad to see if there are any leaks, there are a lot of areas that water can collect without it getting on to the floor and pointing out that you have a leak.

[fraxton]

I wonder if you got a faulty thermostat, not sure on a speed six engine but on some other cars when the thermostate fails it's stays closed, the water in the cylinder head will soon start to boil, and it will push the only way it can go wich is to the expansion tank, I would take it out and poor a kettle of boiling water over it, and see if it opens.
Good luck

[G20RG B]

Had a good look today and the radiator looks ok..
The themostate may be worth checking as mentioned above (thanks). Can anyone tell me where it is on a SP6 engine .

Thanks
George

[Leadfoot]

What level are you filling up to?

Coolant should just be visible in the bottom of the neck of the tank, any more & it'll get blown out.

[gbtvr]

Hi George,

Could be cap, what Temp is the car reading, as leaking cap will drop pressure which will boil the coolant earlier than if cap working correctly.

[G20RG B]

Hi Guys,

Looks like it was a mixture of me overfilling the expansion tank , and not having the cap on tight enough.
Seems to be okay now,, thanks again for all your help.

George