Miller88
NAXJA Forum User
- Location
- Syracuse NY
My 2000 XJs 4.0L was pretty quiet when I got it - the quietest 4.0 I've had.
Over the past few years, it's got pretty chattery. It didn't sound like a broken / cracked flex plate - I checked and the flex plate was not broken and the bolts were not lose.
Hot idle:
https://www.youtube.com/watch?v=Emcfq3BnlzY
Hot restart seems to be the worst:
https://www.youtube.com/watch?v=KYuny4UQM44
To me, it sounds like a broken piston. Which makes sense - it's a 2000, so it is either going to break a piston or crack the head. My plan was (and still is) to run it until it self-ventilates then find a 99 and older engine to swap in.
I was doing some snow wheeling. I have skinny tires. The only way I could go at all was to use a lot of wheel speed. There were a few times where I had it bouncing off the rev limiter - and a few spots where I sustained 4000RPM for a minute or two straight to move.
After that, the engine was whisper quiet. Even on hot restart!
The chatter came back again. So I put it in 1/2 and drive around at 35MPH in 1st gear for a few minutes. Engine was quiet again.
Oil pressure is good. Seems to be too high pitched of a noise to be a rod knock (same pitch as piston?).
But usually high RPM operation causes the pistons to let go if they are broken.
Confused!
Over the past few years, it's got pretty chattery. It didn't sound like a broken / cracked flex plate - I checked and the flex plate was not broken and the bolts were not lose.
Hot idle:
https://www.youtube.com/watch?v=Emcfq3BnlzY
Hot restart seems to be the worst:
https://www.youtube.com/watch?v=KYuny4UQM44
To me, it sounds like a broken piston. Which makes sense - it's a 2000, so it is either going to break a piston or crack the head. My plan was (and still is) to run it until it self-ventilates then find a 99 and older engine to swap in.
I was doing some snow wheeling. I have skinny tires. The only way I could go at all was to use a lot of wheel speed. There were a few times where I had it bouncing off the rev limiter - and a few spots where I sustained 4000RPM for a minute or two straight to move.
After that, the engine was whisper quiet. Even on hot restart!
The chatter came back again. So I put it in 1/2 and drive around at 35MPH in 1st gear for a few minutes. Engine was quiet again.
Oil pressure is good. Seems to be too high pitched of a noise to be a rod knock (same pitch as piston?).
But usually high RPM operation causes the pistons to let go if they are broken.
Confused!