4.3 NOISY all speeds

[johnzonh]

hi guys. before I rip this engine apart or have someone else do it...need some quick thoughts on this one.. 1995 4.3 serial 0F433207 alpha one gen 2 sitting on a bayliner capri. 350 hours on the engine. Anyway I am attaching a video of this engine and at all speeds, in gear or not...I get this stuff. I plan on running a compression check shortly, already pulled the water circulator, belts in good shape and alternator/steering/H2O and crank pulleys solid. Noise seems to come from front of engine...and is not a 'tapping' noise. It is in rhythm with the engine.

known: oil press is great, h20 temp is cool at about 165, everything else otherwise is good. starts right up. No leaks, hoses are cool and oil is clean. Drive makes no noise.

We took it out a bit ago and came back in as I was not happy with the grinding.

 

[Lou C]

Have you tried running it briefly with the belts off to see if it is the bearing in the circulating pump? They will make noise like that when the bearing wears. Every accessory and idler pulley should spin with no roughness whatsoever.
I don't know if the balance shafts on the newer 4.3s make noise maybe others can comment. If you have a mechanic's stethesocope it can help a lot finding noises. Check the alt, p/s pump, circ pump and any idlers.

 

[johnzonh]

yeah I will try it just to see. I did take the pump off and it seemed ok but I know always hard to tell unless we isolate it....will try it no belts for fun. I know a new pump isn't terribly expensive. Also noticed about the same time it started making noses...a burning smell...I was thinking electrical because it had a similar smell. Would a shot bearing in the pump do that?

 

[Bt Doctur]

dosent really sound like a fuel pump rod knock, mor like a rod knock. Remove 1 plug wire at a time , listen , shut off, reattach, pull the next one. If its a rod the sound will stop when the offending plug wire is removed

 

[Rick Stephens]

I'd probably run it with the drive off just to make sure.... you can shove a cutoff garden hose into the water port on the bell housing and crank her up.