Cooling fan on/off

[Turbosix]

Hello, I just purchased my first turbo regal, and are unfamiliar with the characteristics of the vehicle. First the big relay on the drivers was rusted badly causing the fan on all the time. I replaced the relay, and now when the engine is started the fan is off, like it should be.
MY QUESTION IS THIS: at what point, or temperature, should the fan be turning on? I certainly don't want to overheat anything if there is something else that needs attention as well.
ANY help, questions, comments or advice would be greatly appreciated...........thanks

[Keller]

It depends on parameters set in the chip, so its hard to say. There is a good chance it isn't a stock chip, so the parameters aren't likely to be the stock ones. The stock parameter might have been 185-195F - don't recall.

There are two fan levels as well. The higher one is set by a temp sender and ony kicked on when the car reaches something like 220F. Not precisely sure about the temperature, though.

Could probably find the info on this site or in our archives.

[Turbosix]

Thanks for getting with me Scott. And at this point I would like to thank you for setting up this website. There really is not all that much info out there about these cars, as perhaps the Mustang 5.0's. This website I am hoping will help me out some with my GN.
There are deals to be had out there. The 87 I just got, was in Michigan, and the guy wanted to get it out of his garage for the space.
I waited 3 months for him to come down to my price. This car for the area of the country it has been in, is amazingly, rust free. 63000 miles. All stock, with stock type exhaust and air filter. Based on my limited expertise with cars, it looks like nothing has been taken out of its stock condition.
I have considerable experiance with five ohs, and have taken apart quite a few motors, the grand national looks untouched.
Anyway, I don't think there is a performance chip involved with this car, however that would be a pleasant surprise, so I will check on that.
Once again I would like to thank you for this great informational website, and for the insight into what the temperatures I should look for, as far as the fan turn on points.
With an external guage, I can monitor the temp, as the engine warms up, and see what happens.........Thanks

[Turbosix]

Just to close the chapter on this one, I'll describe what happened.
Being unfamiliar with a GN and having just bought one and checking it out for the first time, the fan was stuck on, all the time.
Somewhere I found out that the big relay on the drivers side fender, goes bad.
checking it out, sure enough, this one was severely rusted on the inside of the relay, obviously causing an "on" condition all the time.
Well, being on all the time isn't such a bad thing, as opposed to being off all the time, I replaced the relay anyway.
Now I started the car, the fan is off like it should be.
The question then became, when does it turn on, or more importantly, will it turn on?
Well, i knew I didn't want to test the car to the point where It might get too hot if another related, relay or device wasn't functioning.
Being a backyard mechanic of sorts for many years, I found it advantageous to purchase one of those service manual sets for the Buick GN. I met a guy at the Detroit autorama selling them for over a 150 bucks less than what I see them going for on ebay.
I found out the turn on temps and when the fan turns on.
The fan turns on when the ac comes on, so, I started the car up let it warm for about 5 to 10 minutes, turned on the ac and the fan came on and off regualrly like it was supposed to.
Being confident, the motor was fully warmed, at this point I knew that if everything was working, if I turned the ac off, at some point the fan should kick on by itself, from the relay and sensor combo that senses the motor temp.
The fan turned on and began cycling on its own like it should.
So, now I can drive the car confiently knowing at least that the fan is working.
Thanks