Overheating issue

[TomUK]

On a run, my wife's 1.1 Saxo Desire suddenly began to overheat. Needle rose to the top, red warning light came on. Cooling fan cut in, and carried on for another 5-7 minutes after ignition was switched off.
Checked under bonnet. Top hose to radiator cold, as was the radiator itself. After things had cooled down, checked coolant bottle on side of rad. It was empty. Re-filled it later. It took 1 litre of coolant.
Tested today. Ran for ten minutes or so, temp gauge needle eventually rising to the top. Switched off. Rad and top hose still stone cold.
Is this probably a stuck thermostat, or could the same symptoms be caused by water pump failure? Seems a bit severe to be just an airlock.
Is that the thermostat housing at the end of the top hose?

[axsaxoman]

could be thermo stat , but if you just filled it up without bleeding system correctly , it will do it again
get a coke bottle ,large one, cut bottom off
jam it in top of rad with a rag -- then fill bottle up half way -un do bleed screw to get out air -then run it for 5 mins with water still in bottle .
stop and refit cap when it has cooled

if that don,t cure it then you need to look deeper
but to loose wATER in first instance you must have leak or another problem
could even be a bad rad cap allowing water to come out and not pressurising system
no pressure and water boils at 100c --with pressure it will be 130c--so you need a good cap

[MartinObviously]

Originally Posted by TomUK

On a run, my wife's 1.1 Saxo Desire suddenly began to overheat. Needle rose to the top, red warning light came on. Cooling fan cut in, and carried on for another 5-7 minutes after ignition was switched off.
Checked under bonnet. Top hose to radiator cold, as was the radiator itself. After things had cooled down, checked coolant bottle on side of rad. It was empty. Re-filled it later. It took 1 litre of coolant.
Tested today. Ran for ten minutes or so, temp gauge needle eventually rising to the top. Switched off. Rad and top hose still stone cold.
Is this probably a stuck thermostat, or could the same symptoms be caused by water pump failure? Seems a bit severe to be just an airlock.
Is that the thermostat housing at the end of the top hose?

There is a possibility that it's the water pump, wouldn't be the first time I've seen blades corrode off or replacement pumps failing and spinning on the spindle. very rare though.

Yes the thermostat is right on the end of that hose, its either 2 or 3 10mm (M6) bolts holding it on. Easiest thing to try first.

As above though you need to make sure you bleed it correctly after changing it.

I bleed these with the engine totally off and cold. There's no need to run the engine. With the header of water created by your upside down bottle you simply open the radiator bleed screw until there's no air, close it, then the one on the thermostat housing (which you need to be REALLY gentle with as they snap easily, it doesn't need to be that tight) and finally the one on the heater matrix hose at the top and you must do them in that order.

Excess coolant in the radiator will spill out as you use the car, the full mark is about 1/2-3/4 the way up the side of the radiator.

That's basically the method described on servicebox - which I sadly no longer have access to and it's never failed me.