1993 S-10 Blazer Slight Knocking sound ..

Hello All I'm new here and Like what I've been reading w/ this Forum. I have a Sweet New (old) Blazer 1993 Tahoe 4dr V6 4.3L W engine 94k miles 2wd 4L60e Auto-matic four spd. It has a Slight Knocking in engine/trans area But has over 50 psi at ALL times and Runs Awesome other then this Knocking, Never under a load only when idling or at a Stop in gear/Neutral.. Psi is Still over 50. I got it w/ the Noise and Have Put 4,000 miles on 'er since I got it six months ago.. Seems somebody never drove Her much. I have taken a real Shine to this Little four Dr 2wd and Really Hate to hear 'er Knocking, So does my friends Who rile me About Rod bearings or Crank bearin's.. I know it is neither cuz of the Oil Pressure and how it runs.. Like a Raped ape.. hehe. I thought maybe Torque Convert or Flex plate Area.. Took Serp Belt off to Isoulate noise and its still there. So any Idea's of where or How to find out what is making that Awful noise.. I don't want to drive Her too far away from home and get stranded...No Check Engine lite either. here's what I've done so far .. Drop spindles 2in, 2in rear Blocks, KYB gas-adjust all 4, Electric Fan 2700 CFM/ 16in. Wires,Cap,Rotor,Plugs,Oil,Filter,Lucas oil treatment, 2002 Extreme wheels 16X8, K&N Air filter ,(Stock Air Box) and Sway bar bushings.. That's About it... I Really Like the way She handles Now better then Before... More Like a Car... still want to Put S-10 Extreme Coils in her.. Drops it 1.5 in More in front.. That Should Be it.. oh and a Rear sway bar .. yeah and I did swap out the Muff-ler to a Ravin For fifty Bucks .. Much better Mid range now .. I could use alittle more but I have a V8/283cu in/TH350,3.08one leg'er '64 Elco for that .. Thank For any help in this Thread .. S.A

You could unbolt the torque converter from the flexplate and see if the noise goes away. If it does, then you know it's in the tranny, if not, then you know it's in the motor or exhaust. My guess would be exhaust, possibly loose catalytic converter guts?

Is it a knock or a ticking sound?

Put one end of a piece of rubber hose up to the valve covers and the other end to your ear - if you can hear it ticking, it's probably a lifter.

If it's a knocking, it might be a rod bearing.

Thank You for the replies... I definetly know it is not a Tick. It is a Knock and it Goes Up and Down when I free rev it .. You can hear it Slighty when going up and Down in RPM's.. Never under a Load or Hardly ever if Air is on .. I Checked the AC compressor and All Front engine Motors.. ie Smog pump, Alt,Power steering Pump,water pump,Belt tensioner, Etc .. This Blazer Runs Real Good. I will keep checking it and Hopefully I'll find it and be able to fix it.. I never thought it could be a Cat Converter.. But I'll Check that out. Thx again and I'll check back Soon. S.A PS once Warmed up it is Harder to hear But can be heard if you Really listen.. Maybe I should just get a Louder Exhaust LOL .. hehe.. (o_~) :grinno:

The cat can/will knock when the ceramic element inside breaks up. If you tap on the cat with a rubber mallet or something similar, you should hear stuff moving in there if it has self-destructed.

Happened on a Lumina I used to own - when the shop cut it out, pieces of ceramic went EVERYWHERE.

Thank You.. I will most likely have the Cat converter replaced next week to a High Flow or something else.. S.A :smile: