Well I thought id be brave and jetwash the engine bay after work and all was good till I got home that was.
Only popped inside for 10 minutes to grab some stuff and when I came back out the car was still steaming which was odd, upcon closer inspection I could see flames and embers under the car, luckily Ive got a fire extingusisher in the house and managed to put the fire out without calling the fire brigade.

The cause? Previous shonky alternator/fan switch wiring.

Spend all yesterday rewiring it but cant get the fan to cut in so thats another thing for the list.
Nothing like owning an R5
