I bought a 2000 Blazer LT 4.3L 4x4, I'm going to add cooling fans from a 2002 Malibu to it and remove the fan clutch. This is a multiple ? post due to the nature of the upgrade. I've also read several of the other post's regarding the upgrade to cooling fan's I've done some research but hit a dead end. I was thinking of upgrading the alternator for the extra load of the fans. I am going to use a 3-relay system that can be bought from justchevytrucks.com or a stand alone adjustable set up from a guy in Canada. Both systems will run the fans at 1/2 speed while the A/C is running and full speed if it gets warm enough to kick them on. The system from justchevytrucks is ECM activated for the full sized trucks that have cooling fan relay capability when enabled by a programmer or a Tech 2.


1) Has any one ever tried to use a 130 Amp alternator from a 2000 Yukon? Looks as if it would be a direct swap other than size. Either a longer belt or a smaller (power) pulley is all I need. I work at a parts store and did a counter mock up and measurement between them and so it looks good to go.


2) Does anybody know if the 99 and newer Blazer ECM's have a fan enable like the full sized trucks do starting in 99? I prefer to use this set up if I can. There is enough clutter under the hood and this set up would be a little cleaner install.

 

Look for an ad244 out of chevy trucks. 145 amp. you`ll need a 1 inch longer belt also a dual fan from a concorde fits like it was made for blazers

 

Thanks for the tip on the alternator!!! I am looking at the 2004 unit now.
As far as the fans go I want to keep with GM stuff and wiring. The 2002 Malibu fans fit fabulous. I can add two pieces of 90 degree angle aluminum and drill a few holes and BAM it's attached. The relay set's are pre-wired for the GM fan connectors, that will make it as plug and play as possible there... so far I've mocked up as much as I can without tearing into it and I have the heads off of my Venture for a coolant leak. As soon as it's done with that, I'm going to attack this.

 

My research has led me to believe that 03 and up have a pcu that can be programmed for electric fans. I agree with keeping things GM. I've been looking at fourth gen. F body dual electric fans.

 

Thanks for the 411 on the 03-up PCM, I'll ask a tuner about compatibility. I looked at the 4th gen. Camaro/Firebird radiator and found the core dimensions are 24-3/4" x17-1/4", making it a little narrow and tall for a 2nd gen S-truck radiator of 26-1/4"x 14-5/8". The Malibu radiator 26-1/4" x 14-1/8". It was a perfect match to an S/T-truck rad. Flow should be adequate as well, we shall see...

 

FIY,
I studied the PCM pin out's for several years worth of Blazer's, none of them have a cooling fan relay listed for any connector. So to answer my own question, the 99 and newer S/T PCM's will not control any cooling fans.

 

Over the years, I've seen a lot of overheating vehicles with aftermarket or "adapted stock" electric fans.

I've seen a first gen S10 pickup with the the 5.7L V8 engine, automatic transmission, radiator and fans from a 1996 F body. He didn't have air conditioning, and if I remember right, he had the fans mounted on the front, wired backwards. I'm not sure if that was 100% necessary, but that's what he did. Those fans were barely adequate for the truck in hot weather, and were inadequate for trailer towing. We added an auxiliary transmission cooler to that one, and I'm not sure if that fully resolved the overheating issues while towing.

The 2nd generation Dodge Intrepid (also Chrysler Concorde/Chrysler 300M) from 1998 to 2004 are almost a perfect match for the 4.3L S/T series radiator. The mounts aren't quite right, but bracketry to fit them can be made and it doesn't look too bad. It won't cool as good as the stock fan and shroud, though. I've pulled several of those off of 2nd gen S10 pickups and Blazers/Jimmies that had overheating problems with them. They looked really nice, but the overheating issues were resolved with a new stock fan shroud, a stock fan and a new stock fan clutch.

If you want adequate cooling, it's tough to beat the stock system. If it's properly maintained and fully functional, the stock cooling system will not overheat in these vehicles unless you're operating well outside the designed loads and specs.

The only thing that might give you some benefit is to add a supplemental pusher fan on the front of the A/C condenser, and wire that with a relay that cuts on with the compressor. You could also use a diode and a thermo-switch on the intake to turn it on at high engine temps. A supplemental fan on the condenser coil will help if the A/C isn't cold enough in stop and go traffic, and also can reduce some of the fan noise you get taking off from a long red light in hot weather with a properly functioning stock fan clutch. Mercedes Benz added the pusher fan on the front of the A/C condenser starting with the 1979 S class sedans and coupes. It definitely helps, but it's best in addition to the stock mechanical clutch driven fan.