Hi there just wondered if anyone could tell me why the engine has over heated on my Rev 3 ? It’s blown all the coolant out of the rad cap. After testing I can see that the fan is not coming on so that will be the first clue? I have tested the fan with a car battery and the fan does work when test, so any ideas what it could be? Any help would be appreciated thanks.

Regards

Phillip

Sounds like the thermostatic switch has stopped working. It's a fairly common failure. They are easily available. You can test yours with a saucepan of hot water and a multimeter. People usually bridge them out while waiting to get the new one which means that the fan will run whenever the motor runs. The motor will run too cool at times but at least the coolant doesn't get blown out.

Ok thanks for that, how do you bridge them out? Or test them with out a multimeter ?

Just join the two wires together that fit on your stat,ive used a car fuse,or just a piece of wire.If testing stat in boiiing water just set your multimeter to continuity,if stat open there will be a circuit ,new stats approx £20+ depending where puchased

Take the cable plugs off the thermostat and join them together electrically.

Set a multimeter to measure resistance and measure the electrical resistance across the connections on the thermostat as the wet end of the thermostat heats up. A saucepan of water on a stove works for this. It should drop to zero ohms when the water gets hot enough - somewhere around 80-90 degrees celsius.

Ok thanks for that, how do you bridge them out? Or test them with out a multimeter ?

Ok thanks folks for all your help on this. 
 

regards 

phillip