Fans

[cdt]

My engine cooling fan seems to have stopped working. I've checked the fuse which looked okay and replaced it, it doesn't seem to have made any difference.

I think it was the right fuse, the car has 3 rows of 7 fuses which I think is the layout from the 400SE, I only have a photocopy of the fuse board layout that came with the car. This lists the fan fuse as number 20 (third row, one in from the right). It was a 25 amp fuse. I'll check the other fuses tomorrow just in case.

If it isn't the fuse, how can I diagnose what it is likely to be?

[350zwelgje]

Put two leads to the fan motor, or bypass the switch, to check if they can work. If not it could be something like the fan motor has packed up.

I have only 20 amp fuse for the fan. But it is a single fan setup. And if with two it would be the same I don't know.

Rob

[cdt]

Mine is a single fan, is that normal with a 3.9 litre engine?

Can I just connect the fan motor directly to the battery terminals?

[cdt]

Strange, the fans are working now ...

All I did was turn the fan each way a few times by hand and wiggled the wires a little. The fan did feel a little stiff to turn.

If you are standing in front of the car facing the fan, should the fan be turned clockwise or anti-clockwise?

Would it be an idea to spray any of it with WD40?

[rev-erend]

Check the lead to the fan - one should show a voltage of 12 volts - the other is a negative and is switched to earch when the engine temp needs it.

If you earth the other wire then the fan should work.. unless there is a problem with the fan of course.

You can also run seperate + and - wires to the fan - this is what I've done in the past to check if a fan is at fault.

[chunder]

cdt said:

Strange, the fans are working now ...

All I did was turn the fan each way a few times by hand and wiggled the wires a little. The fan did feel a little stiff to turn.

If you are standing in front of the car facing the fan, should the fan be turned clockwise or anti-clockwise?

Would it be an idea to spray any of it with WD40?

As long as the fan sucks air in from the front and sucks / blows over the radiator then it doesn't matter which way it actually spins !

Spraying it probably won't help as it should be sealed and getting anything into the bearing requires disassembly.

Aside from the fuse it will probably be supplied via a relay - intermittent relay operation isn't unheard of.

As in many previous posts / SH bible an override switch isn't a bad idea.

[cdt]

chunder said:

cdt said:

Strange, the fans are working now ...

All I did was turn the fan each way a few times by hand and wiggled the wires a little. The fan did feel a little stiff to turn.

If you are standing in front of the car facing the fan, should the fan be turned clockwise or anti-clockwise?

Would it be an idea to spray any of it with WD40?

As long as the fan sucks air in from the front and sucks / blows over the radiator then it doesn't matter which way it actually spins !

Spraying it probably won't help as it should be sealed and getting anything into the bearing requires disassembly.

Aside from the fuse it will probably be supplied via a relay - intermittent relay operation isn't unheard of.

As in many previous posts / SH bible an override switch isn't a bad idea.

Thanks for the replies

I was just wondering if I turned it the wrong way by hand if I could damage it.

If the problem isn't related to the otter switch, does a fan override switch help at all?

Edited by cdt on Wednesday 9th May 19:35

[350zwelgje]

Seems something fan internal to me. Turning it by hand probably cleared a few internal contacts and fixed it...
And you are right, if the fan (motor) itself has a problem an override switch won't help.

Rob