95 4.3 engine roars very loudly, what is it?

[red90sixspeed]

Dad's 95 ext cab 2wd truck makes an unusually loud roaring noise. It seems to drive ok but may be a bit down on power. Not sure about the power part as I havent driven another one to compare it to. From a dead stop, floor it and it just barely spins the tires. It is an auto. I have tuned it up. Plugs, wires, coil, cap, button etc etc. Checked timing and bumped it to 2deg advanced vs the 0 deg stock. It sounds like the fan is making all this noise. Is this unusual? Any input would be greatly appreciated.

[Guest Friz]

The fans do make a lot of noise on these trucks. If yours is doing it constantly, maybe the fan clutch is shot. Mine comes and goes, but you can definitely hear that fan turning.

[red90sixspeed]

Well, in contrast mine is very very quiet. You allmost wouldnt know mine was running even when I rev it up. His on the other hand is loud even when you rev it up in nuetral. I thought about the fan clutch and it does seem stiff. I looked at a new one and it seemed the same. Is there some kind of option code (rpo) for a larger fan if you have some kind of HD towing package?

[GreenRado]

Those fans really make a lot of noise.  The fan on my '95 Jimmy w/ 4.3 was really loud, and it seemed to come on at wierd times, like right @ start-up after sitting all night, but it never ran more than 1-2 mins, and did seem to scavenge off a lot of power.  

 

So, if it's running constantly, or even pretty often, something ain't right.

 

Not really much help, good luck.