[CenCal95]

Unfortunately, I am writing this with a new radiator waiting for me to install. The last one I had, which was perfectly fine, was punctured by my passenger side electric fan somehow while driving. I have absolutely NO CLUE as to how something like that happens, but I have the worst luck, so it happened to me. Yes, my electric fans were bolted up as tight as could be. It is also worth mentioning I have an aftermarket fan motor and both fans are wired directly. My driver's side fan is a perfect distance away from the radiator (original fan motor), however, the passenger side bolts up extremely close. I'd say about 3/4 of an inch at best. It is probably just as close or closer than it was on my last radiator that was damaged and if I were to leave it as is, I know it's going to cost me another radiator and another headache. Is there a way to adjust the electric fan out a bit more or is it somehow the fan motor causing it to sit closer? I know this may be a confusing question I am asking here, but I guess I have to ask a confusing question for a confusing situation.

 

[Fred Kiehl]

You may not have the fan seated on the motor completely. If it is correctly seated, the motor shaft may be too long. If you have a P-N-P junk yard nearby, get a fan from a junked B or D body to replace it. There is no way to move the fan frame any further away from the radiator.

 

[Z09B4U]

As Fred said is the fan fully seated on the motor shaft?
Is the fan motor mount in good shape or could the fan motor move in the mount? IE: "cock" or sit at a angle"
Is the lower fan "arm" mount in good shape? A lot of us have a very rusted out part clipped to the bottom of the radiator.
That said these fans are deliberately mounted very close to the radiator.
If the "new motor" is damaged and the shaft "wobbles" you will get a contact.

both fans are wired directly.

If you mean they run all the time you may have proved that it is not a good idea to run the fans at highway speeds.
At some point road speed air is faster than the fans and this starts pushing on the mounts in a way they were not designed to handle. GM expected the fans to be "free wheeling" at some point. I can not remember but I think the fans shut down around 45mph.

 

[CenCal95]

You may not have the fan seated on the motor completely. If it is correctly seated, the motor shaft may be too long. If you have a P-N-P junk yard nearby, get a fan from a junked B or D body to replace it. There is no way to move the fan frame any further away from the radiator.

It’s seating on the motor fine but the shaft is what sticks out too far. I do know someone that has one from a 96 impala, I believe. I’ll be giving that one a try.

 

[CenCal95]

As Fred said is the fan fully seated on the motor shaft?
Is the fan motor mount in good shape or could the fan motor move in the mount? IE: "cock" or sit at a angle"
Is the lower fan "arm" mount in good shape? A lot of us have a very rusted out part clipped to the bottom of the radiator.
That said these fans are deliberately mounted very close to the radiator.
If the "new motor" is damaged and the shaft "wobbles" you will get a contact.



If you mean they run all the time you may have proved that it is not a good idea to run the fans at highway speeds.
At some point road speed air is faster than the fans and this starts pushing on the mounts in a way they were not designed to handle. GM expected the fans to be "free wheeling" at some point. I can not remember but I think the fans shut down around 45mph.

The last shop I took it to wired them directly and had no idea that was bypassed. I’ll be in contact with a reputable shop about that fan fix. Yes everything is in tact, however, the new fan does wobble the slightest when I spin it by hand.

 

[Z09B4U]

The last shop I took it to wired them directly and had no idea that was bypassed.

The standard definition of bypassed: deleting of sensors and control.

The PCM had a multi layer control of each fan. The PCM looks at road speed, engine temperature, is the A/C on, is the A/C system pressure high, and other factors.

If your last shop has both fans running from engine on to engine off you will increase the wear on the fan motors.

The coolant temperature that the PCM uses to turn on the fans is thought to be high. But I personally would chose PCM control over always running fans.

To see some good pictures of fan mountings:

Different fans for HD radiator?

I purchased an FSR LS1 conversion radiator for my 96 SS build but I ran into a problem when I went to install the fans. I took the fans off my old radiator and my first issue was that the clips of the top and bottom did not fit over the flange of the new radiator as the flange was too wide...

www.impalassforum.com

 

[CenCal95]

The standard definition of bypassed: deleting of sensors and control.

The PCM had a multi layer control of each fan. The PCM looks at road speed, engine temperature, is the A/C on, is the A/C system pressure high, and other factors.

If your last shop has both fans running from engine on to engine off you will increase the wear on the fan motors.

The coolant temperature that the PCM uses to turn on the fans is thought to be high. But I personally would chose PCM control over always running fans.

To see some good pictures of fan mountings:

Different fans for HD radiator?

I purchased an FSR LS1 conversion radiator for my 96 SS build but I ran into a problem when I went to install the fans. I took the fans off my old radiator and my first issue was that the clips of the top and bottom did not fit over the flange of the new radiator as the flange was too wide...

www.impalassforum.com

They wired up the fans to run from operating temperature and up without stopping. When the car is turned on from a cold start, they are off. Is it still possible to reverse to previous setting where they turn on and off when needed?

 

[Fred Kiehl]

It’s seating on the motor fine but the shaft is what sticks out too far. I do know someone that has one from a 96 impala, I believe. I’ll be giving that one a try.

Does the shaft stick through the fan, or is it holding the fan away from the motor? If the shaft is the only thing sticking out too far, you may be able to cut it off.

If anyone needs a lower fan mount, I have a few on hand.

 

[Z09B4U]

it still possible to reverse to previous setting where they turn on and off when needed?

As a general or theoretical comment yes. As long as the PCM is not damaged(no reason it should be) the two control wires could be connected to the relays you should already have. This is simple relay wiring, but whoever does the work should look at a original factory wiring diagram.

One of the fan relay sockets (in the engine fuse box) sometimes melts. GM and aftermarket had kits to move the fan relays out of the fuse box. They still used the PCM to control each radiator fan separately.

What reason was given to rewire the fans?

 

[CenCal95]

Does the shaft stick through the fan, or is it holding the fan away from the motor? If the shaft is the only thing sticking out too far, you may be able to cut it off.

If anyone needs a lower fan mount, I have a few on hand.

It sticks through the fan. I wanted to cut the little piece of the shaft that sticks out but I got my hands on another OEM electric fan. I may be in contact regarding a lower fan mount if all else fails.

 

[CenCal95]

As a general or theoretical comment yes. As long as the PCM is not damaged(no reason it should be) the two control wires could be connected to the relays you should already have. This is simple relay wiring, but whoever does the work should look at a original factory wiring diagram.

One of the fan relay sockets (in the engine fuse box) sometimes melts. GM and aftermarket had kits to move the fan relays out of the fuse box. They still used the PCM to control each radiator fan separately.

What reason was given to rewire the fans?

So no tuning would be required for the PCM right? The shop I took it to years ago noticed the fan connector was completely burned and decided to cut it out and directly wire it along with a new fan motor.

 

[Z09B4U]

They may have used on e of the kits I mentioned or made their own then wired it to the PCM. The 1996 PCM is not cheap/easy to "tune"(reprogram) so there is a low probability changes have been made.

Your fans maybe connected and operating properly. From the drivers seat it can be hard to tell what they do and when.

 

[Z09B4U]

The easiest way to check if the PCM is controlling the radiator fans is unplug the PCM temperature sensor and start the car. The unplugged sensor will force both radiator fans to start.

 

[CenCal95]

They may have used on e of the kits I mentioned or made their own then wired it to the PCM. The 1996 PCM is not cheap/easy to "tune"(reprogram) so there is a low probability changes have been made.

Your fans maybe connected and operating properly. From the drivers seat it can be hard to tell what they do and when.

I have a 1995 and I do have it tuned (LT1 Tunercats). To the best of my knowledge, the tuner didn’t change the fans or reprogram them to run at different times/temperature. They have stayed the same, at least since the fan motor was swapped.

 

[Marky Dissod]

To the best of my knowledge, the tuner didn’t change the fans or reprogram them to run at different times / temperatures.
They have stayed the same, at least since the fan motor was swapped.

Although this is technically possible, it's incredibly unlikely.
GM OE LT1 fan-on thresholds are 107°C / 225°F & 111°C / 232°F (unnecessarily close to overheating).
It may not be easy to tell exactly when an electric fan turns on.
(It's easier to notice the dash temp gauge needle tending to linger starboard of the buoy.)

Nearly every 'tuned' LT1 has both fans come on well before 105°C / 221°F.
The most likely thresholds with a 180°F tstat are 95°C / 203°F & 100°C / 212°F.
(This is represented by a dash temp gauge needle that spends very little time starboard of vertical.)
This is more like how LT1-V08 cars behave; their H2Opump temps seldom exceed 221°F.