Modified XJ Cherokee Tech XJ (84-01)
All modified tech questions. If it modifies your XJ beyond stock parts ask it here.
Sponsored by:
Sponsored by:

Knocking cylinder

Thread Tools
 
Search this Thread
 
Old Oct 11, 2011 | 08:53 PM
  #1  
eastonarcher1993's Avatar
Thread Starter
Member
 
Joined: Jun 2011
Posts: 161
Likes: 0
Model: Cherokee
Default Knocking cylinder

I hear this noise in my engine that sounds like a cylinder is rattling and clinking as if loose. I have a 4.0 inline 6. Did this happen to anyone else or does anyone know what's wrong with it. Thanks in advance.
Reply
Old Oct 13, 2011 | 02:03 PM
  #2  
eastonarcher1993's Avatar
Thread Starter
Member
 
Joined: Jun 2011
Posts: 161
Likes: 0
Model: Cherokee
Default

Anyone?
Reply
Old Oct 13, 2011 | 02:39 PM
  #3  
BNJeepsta's Avatar
CF Veteran
 
Joined: Jul 2011
Posts: 2,164
Likes: 1
From: Warren, Pa
Year: 97
Model: Cherokee
Engine: 4.0L
Default

Is it an auto?
Reply
Old Oct 13, 2011 | 03:49 PM
  #4  
AMXJ's Avatar
Seasoned Member
 
Joined: Dec 2010
Posts: 345
Likes: 1
From: So. California
Year: 1991
Model: Cherokee
Engine: 4.0 HO
Default

Could be a carbon knock but those usually go away after running the engine a while. If it's an automatic it could also be a cracked flex plate. How is the oil pressure?
Reply
Old Oct 13, 2011 | 05:26 PM
  #5  
BNJeepsta's Avatar
CF Veteran
 
Joined: Jul 2011
Posts: 2,164
Likes: 1
From: Warren, Pa
Year: 97
Model: Cherokee
Engine: 4.0L
Default

^^^ That's what I'm saying. The flexplate was what was knocking in mine. But it could be low oil pressure. How's the RMS? Also do you have an Aftermarket oil pressure gauge or the stock one in the cluster? I have owned 3 xj's and they all had bad oil pressure gauges. You may also have a dead cylinder. Pull the plugs and look at them.
Reply
Old Oct 13, 2011 | 09:50 PM
  #6  
eastonarcher1993's Avatar
Thread Starter
Member
 
Joined: Jun 2011
Posts: 161
Likes: 0
Model: Cherokee
Default

Dead cylinder? And I just heard a noise today that sounds like the flywheel is hitting the engine but it's not?
Reply
Old Oct 13, 2011 | 09:50 PM
  #7  
eastonarcher1993's Avatar
Thread Starter
Member
 
Joined: Jun 2011
Posts: 161
Likes: 0
Model: Cherokee
Default

It is an auto
Reply
Old Oct 13, 2011 | 09:54 PM
  #8  
JeepinXJ01's Avatar
Newbie
 
Joined: Oct 2011
Posts: 18
Likes: 0
From: Gurnee, Illinois
Year: 2001
Model: Cherokee
Engine: 4.0L I6
Default

Double check your oil pressure and keep an eye on your temp and coolant level. Mine made that noise then a few days later I was adding a jug of coolant. Then it led to a jug a week. Realized I cracked the head. It was really common in 2000-2001 I6s.
Reply
Old Dec 15, 2011 | 03:40 PM
  #9  
eastonarcher1993's Avatar
Thread Starter
Member
 
Joined: Jun 2011
Posts: 161
Likes: 0
Model: Cherokee
Default

Still making this sound but it stops when I hit 45 mph?
Reply
Old Dec 15, 2011 | 04:07 PM
  #10  
cruiser54's Avatar
::CF Moderator::
 
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Check to see that your flexplate to torque converter bolts are not loose.
Reply
Old Dec 15, 2011 | 07:16 PM
  #11  
BNJeepsta's Avatar
CF Veteran
 
Joined: Jul 2011
Posts: 2,164
Likes: 1
From: Warren, Pa
Year: 97
Model: Cherokee
Engine: 4.0L
Default

If it stops when you hit 45 or so then its probably the flex plate.
Reply
Old Dec 15, 2011 | 08:16 PM
  #12  
cruiser54's Avatar
::CF Moderator::
 
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Until the inspection cover comes off and a 15mm wrench is put on the bolts and/or a flashlight is shined up in there, we'll never know.

Studies have shown that more Jeeps get fixed with flashlights and tools than keyboards and monitors.
Reply
Old Dec 15, 2011 | 10:17 PM
  #13  
BNJeepsta's Avatar
CF Veteran
 
Joined: Jul 2011
Posts: 2,164
Likes: 1
From: Warren, Pa
Year: 97
Model: Cherokee
Engine: 4.0L
Default

Originally Posted by cruiser54
Until the inspection cover comes off and a 15mm wrench is put on the bolts and/or a flashlight is shined up in there, we'll never know.

Studies have shown that more Jeeps get fixed with flashlights and tools than keyboards and monitors.
So I'm a little confused. Were you trying to be funny or were you being ignorant and implying that I only know how to operate a keyboard? Either way I agree that the bolts should be checked and that the flexplate should be inspected for cracks. And if you were just being ignorant then plz knock it off. I'm only trying to help as so many on here have done for me.
Reply
Old Dec 16, 2011 | 05:36 AM
  #14  
cruiser54's Avatar
::CF Moderator::
 
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by BNJeepsta
So I'm a little confused. Were you trying to be funny or were you being ignorant and implying that I only know how to operate a keyboard? Either way I agree that the bolts should be checked and that the flexplate should be inspected for cracks. And if you were just being ignorant then plz knock it off. I'm only trying to help as so many on here have done for me.
You are offering excellent advice and I agree with you 100%. Until the OP heeds some of this advice and he or a shop/friend inspects his vehicle it's never gonna be solved.

My point is, he should check the bolts and flexplate. If that's not it, let's go on to something else. Many times in the diagnosis and repair of vehicles, as I'm sure you know, it's a process of elimination. You have to eliminate some possibilities.
Reply
Old Dec 16, 2011 | 11:45 AM
  #15  
BNJeepsta's Avatar
CF Veteran
 
Joined: Jul 2011
Posts: 2,164
Likes: 1
From: Warren, Pa
Year: 97
Model: Cherokee
Engine: 4.0L
Default

Originally Posted by cruiser54

You are offering excellent advice and I agree with you 100%. Until the OP heeds some of this advice and he or a shop/friend inspects his vehicle it's never gonna be solved.

My point is, he should check the bolts and flexplate. If that's not it, let's go on to something else. Many times in the diagnosis and repair of vehicles, as I'm sure you know, it's a process of elimination. You have to eliminate some possibilities.
Oh okay lol just wasn't sure what you were trying to imply. I heard that a loose bolt in the starter can cause a knocking sound as well? Have you hear of this?
Reply



All times are GMT -5. The time now is 03:00 PM.