Will cooling fans run with engine off?
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Will cooling fans run with engine off?
I have a 91 and I'm wondering if the ECM will turn on the primary fan if the engine is over 226, and the key is in the on position, but the engine is not running. Per the FSM, it seems like it should. I can't test this theory yet, (engine doesn't run) but I have a Megasquirt controlling the engine and I am hoping the ECM will still control the fans. I heated the CTS a bit with a small torch, fan didn't come on, but I don't know what temp it was at.
Someone else installed a Megasquirt and said that his fans weren't working, but I don't know the end result.
TIA, Anti.
Someone else installed a Megasquirt and said that his fans weren't working, but I don't know the end result.
TIA, Anti.
Instructor
Joined: Nov 2011
Posts: 147
Likes: 0
From: Florida
Pretty easy to put a manual override switch in for the fan or fans.
I let one run automatically and manually control the other. But you could manually control both.
If you drive it all the time and no one else NP however if any body is going to drive it then you might need to sort out the auto fan situation. On my 86 it is very straight forward. When temp hits predescribed temp fan comes on. Sensors on block not sure where for your year but once you find them you can test easy enough.
I let one run automatically and manually control the other. But you could manually control both.
If you drive it all the time and no one else NP however if any body is going to drive it then you might need to sort out the auto fan situation. On my 86 it is very straight forward. When temp hits predescribed temp fan comes on. Sensors on block not sure where for your year but once you find them you can test easy enough.
Melting Slicks
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
If I park my 86 on a hot day, and switch engine/ignition off, the electric fan (which was already running) will run on. I don't know if this is ECU controlled, and/or temperature regulated, but it does run on.
I think this is a good thing. There is still some thermo-siphon action even with water pump not running, so the fan running helps cool the coolant even when engine is off.
I think this is a good thing. There is still some thermo-siphon action even with water pump not running, so the fan running helps cool the coolant even when engine is off.
Burning Brakes
Joined: Nov 2008
Posts: 1,159
Likes: 31
From: Orange Park Florida
easy mod
I also ran both my fans to two seperate manual toggle switchs with some fancy very small led lights on the load side to remind me they are in manual mode.. They still work perfectly in normal mode.. but i can switch them on manually when desired.
My c4 never runs much over 189 degrees,, yesterday when I drove it when it hit 181 I turned on the fans and it dropped to 170 quickly.. and heck I live in florida.
My c4 never runs much over 189 degrees,, yesterday when I drove it when it hit 181 I turned on the fans and it dropped to 170 quickly.. and heck I live in florida.
If I park my 86 on a hot day, and switch engine/ignition off, the electric fan (which was already running) will run on. I don't know if this is ECU controlled, and/or temperature regulated, but it does run on.
I think this is a good thing. There is still some thermo-siphon action even with water pump not running, so the fan running helps cool the coolant even when engine is off.
I think this is a good thing. There is still some thermo-siphon action even with water pump not running, so the fan running helps cool the coolant even when engine is off.
Last edited by gman35; Dec 14, 2014 at 12:12 PM. Reason: typing error.
