fan not working

22nd November 2011, 20:50

I think I have a fault with my fan so opinions would be very much appreciated

I went for mot retest today and my temperature was going up and then back down which all seemed fine?

The temperature went just above 3/4 mark which made me a little worried as on all GTI's the max mine had all ever gone up to was 3/4 exactly and then went back down

Well when I stopped I got out the car and checked my fan to see if it was working which it wasn't! Well at the time it wasn't spinning!

I turned the car off and unplugged the fan and then used 2 lengths of wire to test the fan and when i put them straight to the battery the fan was working and spinning fine

Any ideas what may be causing this?

I did think maybe the temperature sensor that the radiator has at the top by the top hose but surely the temperature wouldn't give a reading if this was at fault?

22nd November 2011, 21:46

Here`s my thoughts(I maybe wrong)but I believe there`s 2 sensors 1 on the thermostat housing which gives the reading on the temperature guage.The other sensor is on the radiator this one switches the fan on when the temperature reaches a certain level,it maybe this 2nd sensor that is faulty mate.

22nd November 2011, 22:04

Quote:

Originally Posted by stevo67

Here`s my thoughts(I maybe wrong)but I believe there`s 2 sensors 1 on the thermostat housing which gives the reading on the temperature guage.The other sensor is on the radiator this one switches the fan on when the temperature reaches a certain level,it maybe this 2nd sensor that is faulty mate.

That's exactly what I thought myself just a moment ago mate!

As my car did have front damage when I bought it and the radiator was pushed towards the engine a little where the slam panel was bent... Maybe it has pulled a wire of broken the sensor?

Going to check it out tomorrow

23rd November 2011, 19:02

Well I checked the sensor today and it was all plugged in... Anyone have any ideas what may be wrong?

I thought maybe the thermostat hadn't opened but heaters were working fine and all hoses were warm

I see there is like a capacitor before the plug that goes into the temperature sensor could it be to do with that at all?

23rd November 2011, 19:33

Quote:

Originally Posted by Pug106-GTI

Well I checked the sensor today and it was all plugged in... Anyone have any ideas what may be wrong?

I thought maybe the thermostat hadn't opened but heaters were working fine and all hoses were warm

I see there is like a capacitor before the plug that goes into the temperature sensor could it be to do with that at all?

I was just about to say thermostat because I had this exact problem with my Mk4 Fiesta. Temperature went through the roof, fan wasn't turning at all. A change of thermostat fixed it perfectly.

Would warm hoses really indicate that it's working?

23rd November 2011, 19:42

Hoses are all warm and heating all works fine in the car so obviously the thermostat is working for it to open and circulate around lol

Only think I can think of is maybe the fuse in engine bay, Or the radiator temperature switch I'm gonna check the fuse tomorrow and then loop the plug where the radiator switch plugs into to see if the fan comes on

23rd November 2011, 19:45

Quote:

Originally Posted by Pug106-GTI

Hoses are all warm and heating all works fine in the car so obviously the thermostat is working for it to open and circulate around lol

Only think I can think of is maybe the fuse in engine bay, Or the radiator temperature switch I'm gonna check the fuse tomorrow and then loop the plug where the radiator switch plugs into to see if the fan comes on

I'm not that mechanically minded, but I thought if the thermostat broke then it wouldn't be cooling the system, so the fact that the hoses are warm wouldn't mean anything? It would just mean it's still pumping warm water around instead of cooling it? My fiesta's heaters were working - they'd melt your face after a while, but the thermostat still wasn't working.

Just thinking on the spot here bud

23rd November 2011, 19:56

As far as I always knew the water around the engine would reach a certain temperature and then the thermostat would open letting the water circulate around the rest of the system i.e past the thermostat back into the radiator, normally if the thermostat is broken or stuck open the water doesnt warm up as its always flowing around so doesnt head up, or if its stuck shut then it doesnt let it circulate past the thermostat so the hose after the thermostat wouldn't be warm

im sure i will be corrected if im wrong lol

24th November 2011, 16:00

have you checked the fuse in the engine bay fuse box ?

24th November 2011, 16:09

If the stat is stuck shut then no, the water wont circulate to the radiator and the coolant in the engine will boil, causing overheating and thus warp the head, giving you a blown head gasket. A stuck stat wont do this as its always open allowing coolant to flow constantly giving you long warm up times and sometimes thermally shocking the head/block as cold water can just flow right into a very hot engine at the mercy of the water pump/revs.
Anyway that aside..
Is the top hose to the radiator warm (coming from the head to the rad). Also has it got the temp sensor in the radiator? Id check the resistance on it with a multimeter when the car is hot. You can bypass it with a switch so you can turn the fan on at will too if you wish, just to get you by

24th November 2011, 16:13

Quote:

Originally Posted by Gandi699

If the stat is stuck shut then no, the water wont circulate to the radiator and the coolant in the engine will boil, causing overheating and thus warp the head, giving you a blown head gasket. A stuck stat wont do this as its always open allowing coolant to flow constantly giving you long warm up times and sometimes thermally shocking the head/block as cold water can just flow right into a very hot engine at the mercy of the water pump/revs.
Anyway that aside..
Is the top hose to the radiator warm (coming from the head to the rad). Also has it got the temp sensor in the radiator? Id check the resistance on it with a multimeter when the car is hot. You can bypass it with a switch so you can turn the fan on at will too if you wish, just to get you by

On that note, where / how can you bypass the fan? I heard there's two connectors you touch together?

24th November 2011, 16:44

Quote:

Originally Posted by geraintthomas

On that note, where / how can you bypass the fan? I heard there's two connectors you touch together?

Just put some spade connectors on the male end of the plug and wire up to a switch. That should do it and enable you to turn it off and on.

24th November 2011, 19:27

Quote:

Originally Posted by Gandi699

If the stat is stuck shut then no, the water wont circulate to the radiator and the coolant in the engine will boil, causing overheating and thus warp the head, giving you a blown head gasket. A stuck stat wont do this as its always open allowing coolant to flow constantly giving you long warm up times and sometimes thermally shocking the head/block as cold water can just flow right into a very hot engine at the mercy of the water pump/revs.
Anyway that aside..
Is the top hose to the radiator warm (coming from the head to the rad). Also has it got the temp sensor in the radiator? Id check the resistance on it with a multimeter when the car is hot. You can bypass it with a switch so you can turn the fan on at will too if you wish, just to get you by

This is what I described just now, I said I don't think it has anything to do with the thermostat as the top hose was warm... And my heaters were working fine very hot so I knew the thermostat wasn't stuck, Or atleast not stuck shut!

Anyway problem solved now, I checked the engine bay fuse box and found the 30amp fan fuse blown, replaced it with a new 30amp fuse and seems fine... temp went up to 3/4 but soon came back down again so must be working

25th November 2011, 16:07

So have you definitely heard the fan working now? As my brother had a problem with his fan and his car ended up pissing istelf all over the tarmac the week before last. Turned out a switch had failed thus not turning it on. So worth double checking by parking up and seeing if the fan comes on and you visibly see it come on.

25th November 2011, 17:26

Yeah I will check it to make sure 100% it's working.... I won't be taxing the car till the 1st so have a week to sort it anyway lol

I did leave it running for a little bit but was taking forever to warm up lol but will check it either tomorrow or next week :-)