The radiator fuse has gone (40A Midi-fuse in engine bay) should I just replace it or should I do some further investigation to find out what caused it?

Cheers

fuse blows for a reason. possible cause could be the fan relay arcing causing increased resistance, they are known to stick on , so maybe an area to look at, then wiring chaffing or fan faulty.

4 hours ago, james125 said:

The radiator fuse has gone (40A Midi-fuse in engine bay) should I just replace it or should I do some further investigation to find out what caused it?

Before replacing it, I suggest having a good look at the wiring from the fusebox to the fan. Look for missing or broken clips or fastenings, and anything that allows wiring to touch any sharp edges, hot parts, or metal. Wiring faults can badly damage the loom, or even cause a fire.

Try turning the fan by hand (with no fuse in!), if stiff it could overload the circuit.

If wiring is ok, try replacing the fuse once. It just could be an old fuse, bit of corrosion perhaps, reached the end of its life. But, as Ian says, they blow for a reason, so further investigation is needed if it goes again. Fan motor is probably next suspect.

Have noticed it running excessively often? Usually these fans are variable speed, if some sensor failure makes it run fast for long periods, that could stress the fuse.