Really bad engine noise

[rgnavarr]

Every summer my jeep has had a problem with really erratic engine knocks. I found a video clip of an AMC 360 engine that is making the same exact sound as my 4.0L.

AMC 360 Knock

I already tried changing to a heavier oil and putting in some engine treatement but no luck. Also this problem only happens when it is hot outside (above 100) which is common in AZ, i have had absolutely no problems with the noise in the winter. it seems to get worse when it is put in gear but you can still hear it when the engine is idling like on the video.

has anyone had this problem before or know what it might be?

 

[winterbeater]

How is your oil pressure?

 

[kennzz05]

you sure its the motor and not from the torque converter bolts being loose

 

[92DripCherokee]

what youre describing sounds like a connecting rod knock
Rod knocks get worse under load, and at full operating temperature

I dont think this is flexplate, I've cracked and replaced mine recently, they stop knocking or lessen under load, and get better when hot.

 

[clunk]

I almost want to say that I had a similiar noise on my 1990 4.0, but mine sounded a bit different. It could just be my crappy laptop speakers making it sound a bit different though.

I drove it for 3 years with the noise including a few 14 hour highway drives over mountain passes and it never burnt any oil or died on me, but it always worried me.

Anyways, I always had that noise in the hot summer months as well, and in the winter it would go away for the most part. I believe that it was a stuck or sticking exhaust or intake valve.

I "fixed" it for around 3000 miles by using 2 cans of Mopar Combustion Chamber Cleaner, then it came back and I couldn't shake the noise and got tired of worrying about it, so I bought a newer XJ to replace it a week ago and will be selling my old 90 soon. I'll be sad to see it go.

 

[rgnavarr]

problem fixed. i bought an automotive stethoscope and began looking for the problem. The noise was definately coming from the were the flywheel was located so i pulled off the bell housing cover and saw that the flywheel teeth were damaged. pulling out the starter showed that the starter gear didnt retract all the way in after the engine was started. after further examination i found that the mechanic who changed my engine out a few years ago didnt use the right bolt to mount the starter which caused it to malfuntion. i changed out the starter and havent had anymore problems. im just glad it wasnt something more serious.
moral of the story: dont let someone else change your engine out. save the money and do it yourself.