?? Dash switch, second fan?

[forcesevens]

Hey everyone... sorry for being a newbie...
I picked up a second hand atom 2 300 (#14) and can't figure out what the second
fan is for.  There is a lit toggle switch on the dash that turns on the front facing fan.
I traced the tubes back to the engine and I know one of them is for the coolant.
Can someone tell me what the other fan is for?
thanks!

[bolus]

Not sure about a switch on the dash other than the ignition, but the forward facing fan is the coolant radiator fan and the one facing downward is the aftercooler radiator fan (cools the coolant that goes to the supercharger)

[forcesevens]

[quote="bolus"]
Not sure about a switch on the dash other than the ignition, but the forward facing fan is the coolant radiator fan and the one facing downward is the aftercooler radiator fan (cools the coolant that goes to the supercharger)
[/quote]The switch on the dash turns the forward facing fan which is normally off.  Is it bad to drive with it off?
I figure it was for track use or something to maximize cooling :shrug:

[bolus]

Well, that's quite weird because I dont have any fan switches on the dash.  I flip the ignition switch and then the fans are controlled by the engine computer.  The radiator fan turns on when the coolant temp is >200F.  The aftercooler fan runs all the time.  It seems very weird to have a manual switch controlling a coolant fan

Do you have a picture of the switch and the location?  Perhaps it was done by the original owner for some weird reason

[forcesevens]

[DarthChicken]

Definititely something the previous owner added on to the car.

[bolus]

see if you can ask the previous owner how it is wired.  If it controls the radiator fan you want to make sure it still turns on by itself when the coolant temp gets up to 200F.  If not, leave it on all the time.  You dont want to me overheating your engine and blow a coolant line or worse. 

I cant figure out why the owner would do that. 

[forcesevens]

[quote="bolus"]
see if you can ask the previous owner how it is wired.  If it controls the radiator fan you want to make sure it still turns on by itself when the coolant temp gets up to 200F.  If not, leave it on all the time.  You dont want to me overheating your engine and blow a coolant line or worse. 

I cant figure out why the owner would do that. 
[/quote]I have never seen the water temp hit 200.  Usually it hoovers around 180F.
I looked around some more and it looks like the front radiator is connected to a thicker hoose while
the one parallel to the ground has a thinner hose.  The toggle switch is for the front radiator.
Strange.

[rfmarz@frontiernet]

forceseven, it's still pretty cold in GA! The coolant will definitely hit 200 degrees on a tight track. My suggestion would be to drive your car until it warms up completely, then stop and let the engine idle. Watch the coolant temp. and MAKE SURE that the fan turns on when the coolant hits (I believe)~185!!!!! That switch is definitely "aftermarket" and hopefully it doesn't bypass anything. If all it does is manually turn on the engine coolant fan, it's not necessary as long as everything is working as it's supposed to. Maybe it's for the nitrous injection system.

[dingo]

You don't think it could be a post ignition coolant pump override switch to keep the coolant flowing even beyond the timed ignition off switch?
You know that the electric pump will continue to circulate coolant for a while after the ignition is off. Seems like this switch might be to extend that theory.  It's a good way to run down the battery quick smart if so. 

You could check the plausibilty of this hypothesis by flipping the switch when ignition is turned off. Anything? 

[positron]

bolus is spot on.. coolant fan begins to come on at >199F and intercooler pump/fan 10 metric seconds engine run time. There is a I/C pump after run time, but I can't get it to run. We may not have a hot circuit to the fans after the switch is shut off.

[forcesevens]

[quote="dingo"]
You don't think it could be a post ignition coolant pump override switch to keep the coolant flowing even beyond the timed ignition off switch?
You know that the electric pump will continue to circulate coolant for a while after the ignition is off. Seems like this switch might be to extend that theory.  It's a good way to run down the battery quick smart if so. 

You could check the plausibilty of this hypothesis by flipping the switch when ignition is turned off. Anything? 
[/quote]that may be it.  It does turn on the fan when the ignition is off.  I need somewhere to drive hard and bring the temp over 200 to test this

[DarthChicken]

You don't even have to drive it hard.  Tape a piece of cardboard over the front of the radiator and go for a drive.  You'll create heat without airflow... it'll warm up nicely.

[positron]

[quote="dingo"]
You know that the electric pump will continue to circulate coolant for a while after the ignition is off.  It's a good way to run down the battery quick smart if so. 

[/quote]
Which is probably why we don't have a I/C pump/fan afterrun time, since we have a teenie tiny battery.


I'll be more fun getting it hot forcesevens way.. 

[forcesevens]

Is the coolant pump electrical or mechanically driven from the engine?
If it's just the fan, it wouldn't do that much.