Hi guys,

I've just taken a 57 Plate Zetec S as PX and it keeps boiling up on me. It drives fine for 10mins or so, temp gauge doesn't even go up halfway, but then it will boil up whilst driving. When it gets hot the radiator and the rad pipes don't feel hot, whereas the heater pipes are hot to the touch. Also the rad fan doesn't come on, presumably because the temp switch isn't getting hot. If you disconnect the sensor the fan does come on, so I know that it works.

So far, I've changed:

Thermostat
Temp sensor
Waterpump (although on inspection the old one looked OK)

I've just tried some rad flush in it as well, but that hasn't made any difference.

I'm at a bit of a loss of what to try next. Any suggestions?

 

Check the rad cap is holding pressure and relieving properly. Also a sniff test for headgasket failure. Is it bled properly?

 

Thanks for the reply. To answer your question, yes the cap was also replaced.

As it turns out, the previous owner had fitted the thermostat in backwards (and I had blindly followed when replacing). Back together and running nicely now!

Thanks for your advice.