Marble sound from oil pan at idle only?

[35Remmy]

Hey guys...'99 4.0 OHV...I started getting this intermittent "marble" sound from my engine, but ONLY at idle. It's most distinct to my ears at the oil pan, but we all know that sound travels.

It sounds like someone is dropping one marble every, say, 3 seconds, and then dropping 2 marbles a 1/2 second apart every 6 seconds.

Does this sound like a bad lifter?

I had a very similar noise in my 93 Wrangler 2.5L and when I changed the lifters the noise disappeared.

The engine hasn't lost any power, runs strong, and doesn't make this noise besides at idle. Any ideas?

 

[gmanpaint]

Just a guess but maybe a spun bearing? Crank?

 

[celly]

I had a similar issue with a 2nd gen Ex. It was a heatshield on one of the cats. It was loose and rattled so a ton I just took it right off. Problem solved.

 

[Wrench]

Assuming you are using the correct oil viscosity for your use environment I too have experienced slight rattle noises at hot idle in my 4.0L OHV around oil pan when tranny in neutral. Piston slap because of production tolerances. How may miles on engine? Auto or 5 spd.? The flywheel sometimes starts to fail and gives a cracking noise.

 

[35Remmy]

Wrench...it has 91,000 miles...funny thing is, last night it wasn't doing it at all. How the heck does the flywheel start to fail?

 

[ThePhoenix]

my mustang sounded like that when my main bearings went

 

[sethmorgan]

The pulley bearing in the alternator of my '02 Mazda 626 makes this noise.

 

[mshuler009]

I've been told by a Ford Sr. Master Tech that a lot of the times the noise can be caused by carbon build up on the piston face, leading to contact of the head by the piston. The marbles you are hearing are "impacts". Tryperforming a chemical carbon clean. If you have any questions please ask. If done incorrectly you can damage the internals of your engine severely. More than one treatment may be neccessary.