View Full Version : Fan not working
Replaced the sensor on my radiator as my fan wasn't coming on when it should but it's still not working when it should
if I put a live to the fan it will work
paul james
03-09-10, 04:45 PM
Could be the wiring is funked, take off the connector on the sensor, and bridge the two contacts with a bit of wire. If the fan doesn't kick in, then the wiring is too blame. But if the fan does come on - then its another dodgy sensor.
Just bridged the plug and the fan came on
What other sensor could be at fault?
your car is obviously not getting hot enough to get it to switch.....
mayhem used one off a jag i believe.... but i think a diesel one might switch cooler, as they run cooler stats.
paul james
03-09-10, 05:05 PM
Is there enough water/coolant in the system? or maybe a blockage in the radiator? if the sensor isn't in contact with any hot liquid then I suppose it won't switch.
In my experience these sensors are pretty crappy, I've had to replace a few on my novas. So its not impossible that you've been unlucky and got another dodgy one.
It will take a while for the coolant to get hot enough for the sensor to switch, how long have you let the car run from cold while not in motion?
djbrowney
03-09-10, 05:05 PM
is your gagaue correct in the car, might be reading wrong :)
Plenty coolant and no air locks, on my gte clocks it used to go over half way and still not kick in, I have a digi dash now and even passed half way it still dosnt come on
djbrowney
03-09-10, 05:08 PM
have you replaced the temperature sensor ???
nova temp gauges are just not accurate... i assume digi ones are the same..... just cos it reads different doesn't mean there is actually a problem..
benton101
10-09-10, 06:16 PM
get some sort of temperature probe and stick it in the water when you think it should be hot enough and it will tell you the correct heat
have you replaced the temperature sensor ???
Yep
Nova_Tek
10-09-10, 08:04 PM
Thermostat ok? They can sometimes stay stuck and won't allow the water to get hot enough to need cooling down.
Run the engine till its warm or close to when the fan is meant to come on. Place your hand at the top half of the radiator core and see if it's hot. Then place your hand on the bottom half of radiator core and see if it's hot.
They should be equally hot. If the bottom part is cooler, than there is a blockage and the switch isn't being activated. Try flushing/changing the rad.
If not luck still, listen out for any loud hissing in the cooling system. This may point out a headgasket issue, exhaust gasses escaping into the cooling system and over pressurising it. Alternatively smell your cooling system lol
I've lived through these issues on my dads Cav and after messing about with every cooling system part, in the end it was a headgasket issue.
Get a multi meter on the old and new sensor, test it in cold and boiling water to see if you get resistance changes. This should show you if they are working.
I've let it idle till the temp guage goes to about 3/4 on the guage and it still dosnt kick in, the old sensor never had any resistance change when I removed it but never checked the new one
It didn't use any water at all and the water is still the same green as when I put the coolant in so the headgasket fine
I'll test the new sensor and see what it does
bigdan1
11-09-10, 10:18 AM
why dont you wire it up to a swaith so you can flick it on yourself?
i had problems with my digi dash always used to say my petrol was a quater lower than it was lol
Yeah I'm thinking I'm gonna have to anyone have a diagrams I can use to wire one up?
djbrowney
11-09-10, 12:41 PM
i still think your not letting it get hot enough !
Nova_Tek
11-09-10, 07:21 PM
I've let it idle till the temp guage goes to about 3/4 on the guage and it still dosnt kick in, the old sensor never had any resistance change when I removed it but never checked the new one
It didn't use any water at all and the water is still the same green as when I put the coolant in so the headgasket fine
I'll test the new sensor and see what it does
Same with my dads engine mate, no loss of water but it wouldn't let the fan come on for love nor money. Changed the switches over. The top half of the rad would be HOT and the bottom half cool.
Got a replacement engine and all is well.
Lol hopfeully changing it next month if I can find a seh with someone that will pallet it for me
Same with my dads engine mate, no loss of water but it wouldn't let the fan come on for love nor money. Changed the switches over. The top half of the rad would be HOT and the bottom half cool.
Got a replacement engine and all is well.
so the rad was clogged & they swapped the engine????
look swedge.. if the car runs fine, and it isn't a problem, just stop making it a problem...
Nova_Tek
12-09-10, 10:45 PM
No the rad wasn't clogged. We bought a brand new rad and had same symptoms. Cold at bottom hot on top. We tried 3 fan switches, two new and the original. All were working. We also flushed out the coolant and engine too but no luck.
Headgasket had cracked and blowing exhaust gasses into coolant pressurising the system and gave us that problem. Was cheaper to get a new engine that to do a rebuild. Replacement engine with the existing ancillaries and the fan comes on.
i still don't see it... if the cooling system is getting air in it, then the top of the rad will be cold, not the other way round..........air is lighter than water....
Nova_Tek
13-09-10, 12:10 AM
See I was thinking the same, but I tested as much as I could, my dads friend (a long time mechanic) tried his best and check as much as he could and anything we tried was to no avail. Ths was the last case reason and in the end rather than doing the headgasket it was cheaper to buy a good engine. So thats what we did.
Meh, spare engine and parts :)
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