Is this the sound of rod knock?

[rdezs]

If you have the time, and oil analysis most likely would point directly to the component. The last one I sent into Blackstone Labs took just over two weeks though. If you have to drive it, I would drive it gently....

 

[Foggy]

Oil pressure cold at 60, hot idle at 25-30, hot on freeway 40. Did front and rear main seals, pickup tube o-ring and pressure sender three years (40k) ago. Here is a cold start 70° morning facing downhill a bit. This knock (maybe piston slap?) goes away after 15 seconds or so, again, not sure if it is related:

If that noise is cold start only and disappears after a bit, It's piston slap
Very common on the earlier ones

 

[jeremiahm]

The noise from across the driveway goes away, but he noise underneath is persistent.

 

[dkad260]

Is this noise louder at idle when cold or hot?

What happens when you rev it to about 1500 RPM?

I've seen carbon buildup do some weird things, like cant the piston slightly at TDC making a "slap" farther up the bore.

Definitely has a slight hollow sound at one point. With what's been said, check the torque converter bolts.

I have blown a coil doing this on a different vehicle, but maybe disconnect a plug wire and see of it changes. I did this with a motor running and it blew a coil so I would perform this with the motor off...disconnect/reconnect the lead at the coil pack.

Fact it's been like this for 8 months and hasn't gotten worse? A worn rocker will make a lifter tap but that's more distinct.

If you power brake it slightly in gear, does it get louder?

 

[jeremiahm]

Power braking does not reproduce the noise, even up to 3000 RPM.

 

[rdezs]

.... That leads me to think it's more likely under the front timing cover. Wow power braking and under load the timing chain has steady tension. Could be a sloppy timing chain or tensioner is trashed

 

[jeremiahm]

Finally got a good recording of the sound while driving. Phone is mounted in the middle of the dash for this recording. Most obvious between 30-45 MPH. Only occurs under load. This clip is 1500-2500 rpm, no noticeable change in sound. Sound is always there in these conditions, no quiet days. Been doing it for 8 months only becoming a bit louder over that time.

What do the pros think?

 

[dkad260]

Hmm,.can you get a better video around the block at idle for about 20 seconds?

I'm trying to hear about 5hz sound but it doesn't seem like that. Which would indicate a rod bearing. The first video has a hollow aluminum sound so have you verified your torque converter bolts are tight? Also see if you can get a look at the flex plate and look for cracks.

My initial thought is a cracked flex plate.

If you can hold it at 1200 that might make it easier.

 

[rdezs]

If you recall, with a stethoscope the bellhousing was quiet and the noise was pronounced around cylinder number 5. With his oil pressure, I don't think it's a rod or main bearing. Still putting my money on the number five piston pin bushing....

 

[jeremiahm]

Poking around with the stethoscope and the sound seems most prominent from the starter. The ticking sound. It also sounds like the starter is spinning while the motor is running, is this right?