Warm engine on start up = STALL

[polo 1.3]

Hello, my trusty old Polo has started developing a fault.
It only seems to occur when engine is warm (ie. just drove it, popped into tescos for 10 mins).
If when starting from cold its runs perfect, turn ignition and off we go, but when the engine is still warm i turn the ignition and it revs so far then just dies, the solution seems to just rev it a bit and all is fine.
The car Idles fines (no erratic revs).
Any help ?
And let me just say this isn't happening all the time when warm it just seems that when the problem strikes its just been drove & the engine is still warm.

[polo 1.3]

Forgot to add that the "Warm Air Duct" has split at both ends to which i just taped up the splits.
Dont know if this could be the problem ?

[alexperkins]

Temperature sensor is dead mate. Get it replaced

[polo 1.3]

where is the sensor & is it a job i could do myself, not much of a mechanic ?
Also how much for a new sensor ?

[alexperkins]

Its in the thermostat housing - its a pretty easy job. What engine have you got

They are about 10 quid.

where are you based mate?

[polo 1.3]

got a M reg 1.3 and from the oldham area.
I've seen a thread on here about installing one is it true i need to remove some of the coolant from the radiator. ?

[alexperkins]

Mk3 or Mk4 buddy?

No you dont need to do that. Its merely a quick swap job

[Tim_GTi]

Basically it's a small green sensor that when you pull out, coolant comes out. If your quick enough you won't lost much and you can just top it up with a bit of water after.

However if you fancy it you could change your coolant whilst your at it. In which case just disconnect a pipe near the bottom of the radiator and let the coolant run out. Change the temp sensor then refill the coolant