TECH HELP EDITOR
Base vehicle expert
Q Why is my Ducato-based Frankia motorhome overheating?
I have a 2004 Frankia on a 2.8-litre Fiat Ducato. I was coming back from a short break and got caught in traffic. I started to notice the temperature gauge bouncing about a bit and it got up to the threequarter mark so I turned the heater on, which then pushed it towards the red.
Since then, I started the vehicle, got it up to temperature and found it started bouncing again; I turned the heater on and the temperature got it up to three-quarters. A mechanic said it wasn't overheating. I have had a new starter battery recently, could this be the cause of problem?
Neil Pilgrim
A Initially, this sounds like a temperature sensor fault but, as you know, if an engine is running hot, switching on the heater redirects a portion of the excess heat to the heat exchanger in the vehicle and this should help to cool the engine, which you did, but it had the reverse effect.
If I had this in the workshop, I would run the engine until it is hot and check that the coolant pipes are equally warm. This will prove that the thermostat is opening. If not, it will need a new thermostat.
Then I would compare temperature readings on the engine and coolant hoses with the temperature reading via the diagnostic system to find out if the sensor is faulty. It is also possible that a wire for the sensor is trapped, corroded or frayed somewhere in the loom.
Erratic guages can be caused by many things, including
