name that noise?

'89 w/192k miles, auto, 4.0. At idle I hear an intermittent rattle that comes from somewhere inside the motor, not outside pulleys, fans, etc. Happens every 5-10 seconds and lasts only a second or so. It's an internal rattle that resonates the loudest from underneath the engine at the oil pan. Don't hear it at higher revs. Been doing the same sound for 30k miles or so. No damage done yet!? Any ideas. It's a rattle, not a bang, slap or ticking noise.

I think it's due to give birth. LOL...Most likely pistion slap. No alot to worry about unless it gets really loud. 4.0's are loud engines to start with. Juice

Tranny mount..?

Check for loose torque converter bolts - quite a common problem with these. Just a thought...?

Does it go away once the engine warms up? Does it sound like
a diesel? If this is the case it would seem normal

DaveD in Canada said:

Check for loose torque converter bolts - quite a common problem with these. Just a thought...?

Click to expand...

Indeed, a common problem. Or possibly a cracked flex plate, also a common problem.

To check, put tranny in Drive with foot on brake. Press throttle slightly to put load on torque converter.

If noise stops, it is one of these two conditions. Both can be inspected by removing the inspection cover at the bottom of the bell housing. Loose bolts are easy to see. The crack is usually an annular crack that runs concentric to the reinforcing ring where the bolts hold the flex plate to the crank, so the crack can be hard to see.