COOLING FAN PROBLEMS

[BrianG]

With the current snow and cold weather, radiator cooling fans probably don't figure high on the list of thing to check for normal operation. Probably like most people, who leave the climate control on all year round as recommended, I got used to the fans running at half speed, and can't remember noticing the last time the fans switched to full speed, but never had any apparent overheating problems.

Whilst digging a path in the snow to get my car back on the drive after a trip out, I left the engine running (very environmentally unfriendly, I know). After about twenty minutes of idling and reversing, more digging, idling, reversing etc., suddenly the top radiator hose blew off and the temperature gauge shot into the red. Anti-freeze everywhere - YUK- about 3 litres lost in all.

I thought the fans had been running half speed as usual, but I can't be sure, so when the engine got hotter and tried to switch to full speed fans, fuse 14 (front engine bay fusebox, left hand side) blew, damaging the fan control relay module so that I was then left with totally dead fans.

I suppose I was lucky that the top hose came off at home where I could re-attach it and refill the cooling system, otherwise it would be a breakdown truck job if I'd been stuck in traffic when it got too hot. I bodged the fans with some temporary direct wiring so I could get it to my main dealer. The problem turned out to be caused by a chafed wire in the left front wing (where the fan control relay unit lives) shorting out to the body. The two fan fuses are 30amp each, and lots of damage can happen very quickly before one finally pops, so a new fan control relay unit was needed. Fortunately it *only* cost about 39 quid.

I would therefore recommend that owners remember to check that their fans actually switch to high speed from time to time, perhaps when idling after a run. Now that mine are fixed, I see that even in this weather they can still come on briefly. So check fuse 14 if the fans don't ever seem to run at full speed. You'll know if the other fuse, fuse 12, is blown because you won't get half speed fans or the RH fan in fast mode.