I'll start off with, the noise is not constant. It comes and goes, outside temp doesn't seem to matter and neither does engine temp. Although sometimes it seems less when the outside temp is about 50*. When I picked it up, I heard what sounded like a slight ticking from the valve train and an exhaust leak from about the middle of the truck, no biggie. I am fairly mechanically inclined and do all my own work, but have never trouble shot anything major in a motor. I haven't had time to really look into it as it is my dd. I did do an oil change and didn't notice anything out of the ordinary. Running 10w30 and put half a bottle of mmo in. I listened to most of the engine with a poor mans stethoscope.(3ft screw driver) on various sections of the motor and valve cover and oil pan. I didn't hear anything that sounded bad. At the time the clanking was minimal.

I think there are two separate issues/noises. The clanking is the one I am most worried about. Piston slap, broke skirt, or flywheel? I have poured over the forums and found that xj's can be very noisy, but this is a bit much.

When I get a chance I am going to pull the pan and valve cover, but at the moment it's just noisy and doesn't seem to be losing any power.

So here is a video(for the audio) of a drive home from work. It was about 30* or so outside. It's pretty noisy at from the start and almost goes away by the 11:20 mark. Then at 18:21 the clanking starts for a bit, ending with more at the 21:40 mark. It's 22min long, but can get the jist of it by skipping through.


I am just trying to get some ideas of what to do next and what to budget for, I think a jy motor is in the near future, but would love to be able get a few months out of it if I can fix it in a weekend.

Thanks

Jeff

 

From the way it sounds when you're idling towards the end of the video, I would say it's rod knock. But it could also be loose torque converter bolts, so I would check that first since it's easy to get to and free. Just pull the black inspection plate off the trans and see if any of the bolts are loose.

Regardless of the temperature, it does seem like the noise follows engine rpm. Earlier in the vid it sounds more rapid like valve train noise, but later in the video it sounds slower like rod knock. You wouldn't know for sure unless you drop the oil pan and try and move around each connecting rod to see if any are loose.

 

At the beginning it sounded like rod knock b/c it increased with load and eased off when you let up on the throttle BUT at the end it sounded more like a rattle similar to a loose flex plate

 

Thanks, kinda what I expected, but wanted another opinion or more. I'm going to try at a minimum to check the flex plate. If I have time I'll pull the pan.