Hi Guys, I've just bought a 2002 45 150 Leyland Daf Curtain Sider, 7.5 Tonne. For some reason, during a journey, the engine temperature needle randomly shoots up to maximum, and the engine warning light comes on... after 20 seconds the temperature returns to normal and the cab heater fans blow warm air again!.... I've tried replacing the Thermostat and the water pump, but the problem is still there! Anyone else experienced this??? Thanks in Advance

Darren, November 2014

I know nothing of motor vehicles so i am not qualified to offer any help or advice - a better person than me should come along and explain the likely cause...

If the over temperature reading suddenly appears and just as suddenly returns to normal then it's very likely that the temperature instrument is telling lies - engines do not warm up and cool down so rapidly - there's a lot of latent heat in a hot engine - this 20 second return to normal suggests a fault in the measurement and display system rather than with the temperature of the engine itself.

http://en.wikipedia.org/wiki/Engine_coolant_temperature_sensor

Good luck...

Clarkson, November 2014