Ok, here it is. Temp guage on Escort 1.6 Zetec not working. The top thermostat sensor (grey) looked new as if it had been replaced in a previous life. The bottom sensor (black) was smothered in oil and when removed, you could see it was damaged.
No problem, replace sensor right. Well I had replaced cam-belt kit, aux drive belt & water pump so wasnt expecting any problems anywhere else.
As I allowed the engine to idle after fitting all the above, there was a horrible smell or melting plastic and then a flash-bang and the new sensor literally blew out of the brass fitting!
When I looked at the old sensor, it had obviously done the same, but just melted a bit and went open cct.
I dont want to keep throwing sensors at it as they will all explode & although entertaining; wont fix the temp guage.
If I dont get anywhere I will replace sensors with an older type & fit an external temp guage; However has anyone got any idea?
I am a pretty good mechanic, but auto electrics, ECU's - these are the things of Satan!