Cooling fan always on high

Hello, I recently purchased a 76 coupe with a 1995 LT1 engine, trans and computer from a donor Z28.
The cooling fan runs full out, all the time and it’s driving me crazy. Sounds like there’s someone sitting on the bonnet with a leaf blower running on high.
My question, did the person that performed this engine conversion forget to install some sort of regulator (thermostatically) that would control this cooling fan?
Thank you,
Phillip

Hi Phillip,

Do you have your air con switched on? This will force the fans on. This is what happens on my LS1 engine XJ6.

Regards Rob.

Rob,
Thanks for the reply. The previous owner did not complete the installation of the after-market AC. It does not have any of the hoses and lines installed (these will need to be custom built), and I do not believe the electrical has been hooked up either.
I am having a very difficult time finding a shop to do this work for me. This is an area that I have absolutely no experience with.
Sorry for the side track and back to the fan problem. If, and when, I get the AC hooked up, could that perhaps then somehow control the fan speed?
Thanks again,
Phillip

This might take a lot of sleuthing. My lump is similar. OBD I, rather than the OBD II PCM you seem to have. Or is it ???

The PCM manages the two fans in my car. It relies on an engine temperature sensor.

Separate and apart from the sensor for the facia guage.

  1. Track down the PCM control feature and correct it.
  2. Wire the fan (?) to an after market thermocouple sensing in the radiator fins.
  3. Wire in manual control. Caveat, Extra care needed. I did that early on in my conversion. But abandoned in favor of the PCM control later.

I sure do like my LT1.

Carl

Carl, thanks for the reply. I’ll put on my S. Holmes hat and get to work. Wish I had a Watson to assist.
I’ll report back with my findings.
Thanks Again,
Phillip

This was way too simple. I did some looking at my fan wiring and there is no form of a temperature switch installed to control when the fan was to run. They just direct wired into the ignition system so that the fan runs ALLstrong text**** of the time. I checked with summit (Vintage Air) and found a Fan in Radiator Switch that I can install in the drain plug and wire it to the fan. It’s adjustable so I can set the fan to run and not run at a specific temperature. Amazing what a little “looking beyond your butt” will do for you.
I’ll post an update once I install the parts and see how it works.
Can it really be this simple?
Thanks again for your help,
Phillip

Welcome. solutions are always great.

But, still curious as to why the PCM management feature is not included.

Carl

Carl,
Please excuse my ignorance. I just recently went from a 1939 Ford to this 1976C lump and I am really clueless on this “computer stuff”. I need to do some more reading and try to get caught up on 40 years of technology.
Thank you,
Phillip