General Overheating

[Twilight Johnny Atom]

I posted this elsewhere and got virtually no response so I hope nobody minds if I make it in to a new thread. The car overheated the other day and I suspected it was because the fan wasn't cutting in as it had done the same once before.

I checked the fuse in the fuse box by the battery first and was surprised to find there was no 30amp fuse for the fan, and that even if there had been it would only connect to something on one side of the fuse lugs - nothing at all on the other side. That can't be right, surely?

That probably doesn't make sense so I've taken a picture. New 30a fuse in place to show roughly where it would go:

As you can see there is a yellow connector beneath one side of the fuse lug and nothing below the other side. Does anyone know if something has become disconnected or fallen off. Alternatively, is this normal (maybe the 'piggyback' 30a fuse is the fan fuse?) and do I need to change the temperature sensor or fan relay? If so, Fiat part numbers would be handy if anyone's got them.

I've refilled and bled the cooling system and it is actually cooling pretty well but I'd like to get to the bottom of this at the weekend.

 

[banner]

Unfortunately I can't see your pictures as I'm viewing this at work and photo hosting sites are blocked

Have you tried letting the car get up to temperature and seeing if the fan switches on? Just letting it tick over for a while will be enough for this to happen.

 

[Twilight Johnny Atom]

That's the thing, I'm pretty sure it isn't because I left it running for just that reason and the fan didn't cut in at all. I had to switch it off and do something else so couldn't leave it running for ages but it was certainly long enough for the fan to cut in I'd have thought. The fan isn't running when I stop after a long run either so I'm pretty sure it's not working and I'm trying to track down what is likely to be faulty.

 

[Alan.D]

Sorry for not replying to the other thread I cannot think why it would be like that unless the connector to the left has fallen in?

You can test the fan by disconnecting the plug to the switch and connecting a wire between the two contacts on the plug. At least that will tell you if the fan is working.

 

[LittleRedB]

I am not 100% sure as I have not checked the schematic but you might find that the missing fan fuse is for cars with air-cond!

I would suggest that the temp sender is at fault or the fan itself has packed up, first step would be to disconnect the fan and try adding an external 12v supply to it to see if you can get it to work.

The good thing is it will be a fairly basic circuit so it should not be too hard to track down. Also, have you checked the fuses under the passenger footwell, just have a look and see if there is any that have obviously blown. The previous owner of my car could not get the front fogs to work, he changed bulbs and the switch and then finally gave up! Turned out that he did not know there was a bank of fuses under the plastic cover in the passenger footwell, 20p fuse and they were working again!!

 

[Twilight Johnny Atom]

The first thing I did was to check all the fuses in the footwell in case there was another one but there isn't. If somebody could take a peek under their own engine compartment fuse cover at the fan fuse to see if theirs is the same that would be really handy, before I go hunting for something that wasn't ever there!

Thanks for the replies so far. I'll get this sorted at the weekend and report back.

 

[neil_bb77]

Hi, just had a look at the fuse's under the engine in my B and this is what it looks like, hope it helps! I dont have air con.

 

[Ilkka]

Haven't looked the wiring diagrams, but I suppose that the upper (in your picture) fusebox is for standard equipment and lower for optional extras, as Neil's fuses and the markings on your upper box do match.
Open the upper one, hopefully you'll find a blown fuse underneath.
If not, then you'll need to check the fan itself or the temperature switch...

 

[LittleRedB]

Hi, just had a look at the fuse's under the engine in my B and this is what it looks like, hope it helps! I dont have air con.

View attachment 47944

Do you have air-cond?

 

[neil_bb77]

Nope, no air conditioning in mine

 

[docorangepeel]

Is the fan fuse not the 30A fuse thats on its own with the plastic cover over it?

 

[BILL33]

My car ,Ac but no ABS

 

[RnRollie]

My car ,Ac but no ABS

interesting.. its the same thing (but different).. there are only three (3) contacts....

strange

 

[BILL33]

I will remove the ABS fuse,no need to carry the extra weight.



I must find a "Alleggerita" sticker

 

[alexces]

hello,

I have a question regarding the cooling system.

On the top of the coolant tank, behind, there's a horizontal tube. I should see the coolant getting in the tank from that pipe? I don't know how should the system work.

thanks

 

[s130]

Simple answer, YES

If the system is correctly bled of all air and topped up, then, at engine speeds over idle (say 2000rpm +) and when the car is warm, there should be a steady return flow into the header tank via that rear top feed hose.