Rattling in engine

[Beatjeep]

Tried searching for this but didnt come up with much...


THis seemed to occur after I changed the oil from the previous owner. I hear a rattling noise in the front area of the oil pan which is much louder when the engine is cold then when it has warmed up. When it warms up I can barely hear it. Oil pressure on the gauge reads just above 40 at idle (if thats correct).

Should I be worried about this or not since the oil pressure is quite good?

Jeep is a 97 2dr 4.0 w/ 171K miles.

 

[RichP]

The previous owner could have put in 50w oil to hide this sound but thats neither here nor there. Just keep an eye on the oil pressure, might want to consider putting in some sea foam and do a couple of quick oil changes to clean out any stuff thats in there. Keep an eye on the dipstick and when the oil turns black and you can't read the marks thru the oil change the filter and add a quart. As for the noise, with it off reach down behind the harmoic balancer, thats the big bottom pulley, feel around back there, there is a timing cover that is held on by bolts, on my 98 at 300,000 I was replacing the water pump and had the all the stuff out of the front of the engine, noticed 4 or 5 of mine had backed out, the only thing holding them in was the balancer. After that I never lost that 'mystery' quart between oil changes...

 

[Matthew Currie]

Does the tone of the noise change much with load? If it's just a general rattle that gets better when the engine heats up, it could be piston slap, which is pretty common on some 4.0's, and seems to be harmless enough. My slappy 95 has remained otherwise happy through 260K miles.

However, a bad water pump, among other things, can mimic the normal slap. So check your water pump.

If it's piston slap, thicker oil won't help at all.

 

[Beatjeep]

It doesnt change with load stays pretty much the same yet goes away as the engine warms up...I actually used a Fram filter and I heard that these filters are notorious for producing a clicking noise...:dunno: