Why does cooling fan go off with ignition?
#1
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Why does cooling fan go off with ignition?
I've noticed during the hot weather that the engine cooling fan is coming on more - obviously really.
However, why does it go off when the ignition is switched off? Surely it should stay on irrespective of the ignition if the engine needs cooling down?
Would it not be a good idea to source the location for the wiring for the cooling and wire it to a constant +ve feed to ensure the engine is cooled properly - ala R5 GTT for example.
However, why does it go off when the ignition is switched off? Surely it should stay on irrespective of the ignition if the engine needs cooling down?
Would it not be a good idea to source the location for the wiring for the cooling and wire it to a constant +ve feed to ensure the engine is cooled properly - ala R5 GTT for example.
#3
Perhaps because as the engine is not running the water pump will not be either, making it a worthless exercise having the fan on???
I don't know much about these things though!
Matt
I don't know much about these things though!
Matt
#7
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Originally Posted by Cider boy
Perhaps because as the engine is not running the water pump will not be either, making it a worthless exercise having the fan on???
I don't know much about these things though!
Matt
I don't know much about these things though!
Matt
Does anybody perceive any dramas if I wired the cooling fan to a constant +ve?
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#8
Originally Posted by EddScott
Does anybody perceive any dramas if I wired the cooling fan to a constant +ve?
Matt.
#9
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On most cars Edd that is exactly how the electric fans work. Not exactly sure about the Scoob, but maybe what happened with my car last Sunday can shed a little light.
I took my JDM MY99 wagon for a bit of spirited driving When I stopped first the turbo timer kept the engine running for about a minute while it cooled down. The engine cut and initially so did the cooling fan. However about a minute later the cooling fan kicked in again. There is usually some hysteresis in cooling fan control, kick in at say 95 deg C and cut out when the temp drops to say 90 deg C. Maybe when the ignition is cut at between 90 & 95 deg C the fan cuts too. With my car on Sunday I guess the heat soak, heat coming of brakes, turbo etc was just enough to send the coolant temperature back over that upper threashold again.
Not sure if I'm right, but it sounds convincing
I took my JDM MY99 wagon for a bit of spirited driving When I stopped first the turbo timer kept the engine running for about a minute while it cooled down. The engine cut and initially so did the cooling fan. However about a minute later the cooling fan kicked in again. There is usually some hysteresis in cooling fan control, kick in at say 95 deg C and cut out when the temp drops to say 90 deg C. Maybe when the ignition is cut at between 90 & 95 deg C the fan cuts too. With my car on Sunday I guess the heat soak, heat coming of brakes, turbo etc was just enough to send the coolant temperature back over that upper threashold again.
Not sure if I'm right, but it sounds convincing
#10
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Originally Posted by EddScott
I guess but then it still works when the engine is off but the ignition is on.
Does anybody perceive any dramas if I wired the cooling fan to a constant +ve?
Does anybody perceive any dramas if I wired the cooling fan to a constant +ve?
Can't see any harm in making the feed to the cooling fan +ve so if the engine is hot enough for the fan to come on in the first place the fan will stay on until the senor turns it off rather than the ignition.
#11
If the engine is off the water pump is obviously off too so water circulation will be minimal. If you wire the fan to a constant +ve will it not run continuously until the battery is flat? Just a thought...
#12
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Originally Posted by EddScott
Would it not be a good idea to source the location for the wiring for the cooling and wire it to a constant +ve feed to ensure the engine is cooled properly - ala R5 GTT for example.
So basicly depends where the rad switch is fitted on how well it ill work .
We used to wire carb cars to constant feed to help prevent fuel evapouration during hot weather using a heat sink temp switch to turn the fan on and a 12 minute timer relay , this is an option you could use via an additional timer relay and wiring .
#14
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Originally Posted by supertouring
My fan comes on for the air-con. Turn off the air con and off goes the fan goes off.
I've not checked out my scooby yet (only had it a month !), but that's an older peugeot set up !
#15
On my old fords (Rs Turbo & Cosworth - I know), the fan would stay on after the engine was cut off - I was always told to run the engine after a 'spirited drive' until the fan did cut in so the fan would move the still, hot air out of the engine bay.
However it was more than likely cr@p wiring....
However it was more than likely cr@p wiring....
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