what is that noise

[jm297667]

sometimes when i start my bravada it is pretty loud. Not out of the rear exhaust but from under the hood. I had an S10 with the same motor(4.3 vortec) and it did the same thing. I have heard blazers do it as well. What the hell is that?

[Chris Stewart]

If it's a roaring noise, it's the fan clutch engaged...it goes normal after a few seconds, jes' consider it a sound to reassure you that it's still working correctly.

[ericn1300]

my 93 Astro fan was the worst, a loud roaring noise on acceleration. my 92 Bravada isn't quite as noisy, but i've been looking at electric replacement fans like this one:

http://www.paceparts.com/index.asp?P...&ProdID=117155

anyone have any experience with these? claims to increase hosepower and gas mileage, which would be nice.

also does anyone know of light weight pulley replacement kits for the 4.3 engine. the guys on the Grand Am claim they get a 10hp boost by swapping out the pulleys. might be a good combo project.

[ericn1300]

Originally Posted by ericn1300

my 93 Astro fan was the worst, a loud roaring noise on acceleration. my 92 Bravada isn't quite as noisy, but i've been looking at electric replacement fans like this one:

http://www.paceparts.com/index.asp?P...&ProdID=117155

anyone have any experience with these? claims to increase hosepower and gas mileage, which would be nice.

also does anyone know of light weight pulley replacement kits for the 4.3 engine. the guys on the Grand Am claim they get a 10hp boost by swapping out the pulleys. might be a good combo project.

I posted this message on the Blazer forum and got some good info. if interested check out:

http://www.automotiveforums.com/vbul...d.php?t=467367

still looking for info on light weight pulleys though.