Hi my m8 has a 1998 VW Polo 1.4.. Changed the thermostat and checked that the housings plastic bit was ok, it is ! It still over heats at idle,he has told me the heater in the car does not get any heat since it started over heating before the stat was changed but the heater hoses do get hot.. He had someone tell him it is probablly the head gasket but I would think there would be some signs of oil in water, water in oil or loss of fluids and there is none of that..
Any advice would be great
Thanks

Ron, July 2009

Ron
Hope all works out, are you aware of a company called French German and Swedish Check then out for VW parts via Google

Maurice, July 2009

Maurice Thank you !
There is a large variation in temperature between top and bottom hoses as the engine warms up!
The electric fan does come on when left running..
I think it can be safely said it is the water pump as I have seen on the internet the impellers are prone to break off..
Thanks for your help Maurice, very much appreciated !

Ron, July 2009

I guess it could be a water pump and you may be able to establish this by a large variation in temperature between top and bottom hoses as the engine warms up.
The other thing - you may have already thought of- is the cooling fan, if electric does it cut in if engine is left running and vehicle is not moving. If viscous it can be checked with a stiobe light.

Maurice, July 2009

Could it be the water pump ?
Thanks

Ron, July 2009

A few ideas
Get rad cap / Expansion tank filler cap checked for correct function or replace.
Flush out the cooling system (dont forget once all is okay to replace anti-freeze)
When refilling bleed system to ensure no air locks with the heater in on position.
Check oil level has it gone up if so water may be getting into oil -headgasket failure

Maurice, July 2009