Lets talk cooling fans for a bit here. On some of these 87-91 models, at least 1 or 2 cooling fans are found behind the radiator. I have been paying close attention to these fans because I had my rad changed yesterday. On my car in particular, I have the heavy duty system, which includes 2 fans. 2 fans are standard on SSE models and optional on LE and SE trim Bonnevilles.

Under what conditions would these fans come on? Is the primary fan on all the time? Does it come on when the engine reaches a certain temp? Does running a 180T-stat affect the running of these fans. I went for a little drive after coming home from the shop to get the rad and I noticed when I popped the hood at home (engine on) the fans were not running

Is this normal?

I'm not sure... but I suspect temp has something to do with it. I also believe AC will turn one or both on.

I noticed on hot days after I've driven for a while, if I stop and check, the larger fan will be on, but I've never seen the smaller one on... except when I plug in my code scanning tool... then both turn on. (Must be a function in the tool to help test to see if both are working.)

OK..what if your AC doesn't work anymore :?

they shouldnt' be running all the time anyway, only when certain temps are acheived.. I have two fans.. I've never seeen them come on. lol. My temperature gauge never seems to go over 200*. :?

Perfect...2 fans that never have to be used. I suspect my cooling system and t-stat are doing their job. The ol 3800 never gets hot enough to justify the fans.

i know the second smaller fan comes on a few minutes after you turn on the AC.

i got the regulator Don. Its gonna be a busy night.

I will get to the regulator tomorrow. Many many kudos to you sir

As for the fans, they look pretty, so maybe I will let that car of mine get stinker hot and see if they come on. If I end up keeping the car, then the AC rebuild will be next spring.

We'll see

88 and earlier will just turn the fan behind the radiator on at half speed with a/c on. 89-up will turn both fans on at half. They shift to HI when the coolant hits 107C/226F with the stock PROM. Mine never gets over 190F at idle with the a/c on in a Florida summer day.