OK...here's one for the engine gurus.....I have a noise (for the past 2-3 weeks) coming from the lower part of the engine. You can't hear it from the top...only when you get underneath (more on the passenger side than from the driver side). The noise is very similar to that of "ice in a glass and you shake the glass"....sort of "metally?" It's there when the engine's both cold or warmed up....doesn't get louder just stays the same. I checked the exhaust... all tight. I checked both heat shields for the spark plugs....tight and quiet (when you thump them). I changed oil last week (Castrol GTX with a K&N filter). It sounds like it's coming from (heaven forbid) the oil pan. On a similar note, about 3 weeks ago, I had a "noise" coming from under the dash, took the dash panels out, tightened EVERYTHING I could, put it all back together...the noise was still there....finally tracked it to the wiper motor being loose...so even though the noise is "coming from one spot"...the cause could be somewhere else...so I hope even though it appears to be coming from the oil pan....MAYBE the cause is something other than....lower unit stuff!!! The engine runs strong and smooth....so any help would be greatly appreciated!!

 

just guessing here but have you checked the catalic converter shield? lets hope its not your oil pump going south...pressure unchanged? have you drained the oil and looked for metal particals? nevermind,its usually to late when they show anyway.Exhaust hitting anything?fuel pump tight?Last vett i worked on(76model),that was loose.lets hope nothing is hitting the inside of the timming chain cover as well.

 

I see you have stock headers. Did you remove the heat riser valve in the passenger side header? If it is still there, and I can see in the picture the actuator is not there it will rattle.

 

Oil pump pick-up may have come loose or fallen off

 

It just got weird... This past weekend I had changed the oil (4 Qts of Castrol GTX High Mileage 5w-30w, 1 Qt of Lucas Oil Treatment & a K&N Filter). Noise from the lower unit became more noticable.

Talked with my mechanic and he stated that oil was to lightweight and I should go with a heavier weight......SO I replaced the oil with Castrol GTX 10w40, 1 quart of Slick50 (got it as an Xmas gift last year...so I thought I'd go ahead and use it)and WHAM the noise just about disappears. The engine runs strong and true....no smoke, spark plugs are clear.....so

What the heck is that telling me??????

 

10w-30 should be fine,..perhaps the thicker oil reduced valve train noise. You might adjust your rockers and return to the 10w-30. I don't like thick oils,..hard on rings, hard on distributor/cam gears, hard on mileage and probably reduces HP.

I built a 496 once that made a sound like what you describe. Turns out the one-piece-steel-insert oil pan gasket I used wasn't notched for my crank. Are you running a stroker?

 

Perhaps oil change-noise change coincidental.

Starter drive hitting ring gear?

Flexplate cracked?

Flywheel dustshield loose/hitting ring gear?

Other than cracked flexplate ... these others could eventually subside as wear creates clearance.

 

does the noise return when the oil warms up? I am starting to think the noise you hear is the engine knocking on your wallet. Take off the oil pan and have a look...shouldnt take more than a few hours to have it off and back on again. A fix now just might be lots cheaper than ....