Jeep 3.8 strange sound
03-07-2018, 07:14 AM
#1
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Jeep 3.8 strange sound
I googled and searched a whole bunch but want other opinions. 3.8L Auto. 64k Miles.
Under accleration (mostly up hill when there’s more load) I have a bad rattle type sound. Almost sounds like something lose somewhere in the exhaust. I put clamps over the exhaust crossover so its not that. And I don’t think it is pinging but I’m not sure what that sounds like. Just sounds too metal ish.
It has gotten worse over the last year I’d say for sure. Barely did it last spring. Temps don’t seem to make anything worse. Maybe some. Jeep doesn’t burn any more oil than before. No loss of power.
And no engine codes
Thoughts?
Under accleration (mostly up hill when there’s more load) I have a bad rattle type sound. Almost sounds like something lose somewhere in the exhaust. I put clamps over the exhaust crossover so its not that. And I don’t think it is pinging but I’m not sure what that sounds like. Just sounds too metal ish.
It has gotten worse over the last year I’d say for sure. Barely did it last spring. Temps don’t seem to make anything worse. Maybe some. Jeep doesn’t burn any more oil than before. No loss of power.
And no engine codes
Thoughts?
Last edited by silverbullet88; 03-07-2018 at 07:17 AM.
03-07-2018, 07:33 AM
#2
JK Jedi Master
If it has a tinny sound, it could be a heat shield. There's a few of them under the JK.
It could also be detonation, in which case you need to address it before it causes serious problems.
It could also be detonation, in which case you need to address it before it causes serious problems.
03-07-2018, 11:26 AM
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03-07-2018, 02:14 PM
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I am going to try higher octane fuel to see if the sound goes away. I have also considered the sound is from the honey comb coming apart in the catalytic converter, although I would think that would throw a code. Thoughts? Maybe I will try to make a video
03-07-2018, 03:25 PM
#5
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I googled and searched a whole bunch but want other opinions. 3.8L Auto. 64k Miles.
Under accleration (mostly up hill when there’s more load) I have a bad rattle type sound. Almost sounds like something lose somewhere in the exhaust. I put clamps over the exhaust crossover so its not that. And I don’t think it is pinging but I’m not sure what that sounds like. Just sounds too metal ish.
It has gotten worse over the last year I’d say for sure. Barely did it last spring. Temps don’t seem to make anything worse. Maybe some. Jeep doesn’t burn any more oil than before. No loss of power.
And no engine codes
Thoughts?
Under accleration (mostly up hill when there’s more load) I have a bad rattle type sound. Almost sounds like something lose somewhere in the exhaust. I put clamps over the exhaust crossover so its not that. And I don’t think it is pinging but I’m not sure what that sounds like. Just sounds too metal ish.
It has gotten worse over the last year I’d say for sure. Barely did it last spring. Temps don’t seem to make anything worse. Maybe some. Jeep doesn’t burn any more oil than before. No loss of power.
And no engine codes
Thoughts?
03-07-2018, 06:20 PM
#6
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I had a similar sound on mine, it was one of those tiny chincy heat shields on the section of exhaust pipe where both exhaust heads merge. It was a very fine crack on the weld that made the shield chatter per say. Local shop mig welded a bead back on it and problem solved.
The sound is almost like when you are about to stall a manual trans or start in 3rd instead of 1st. As in Sometimes the rattle has louder “rattles” within the same session of rattle. If that makes sense
03-08-2018, 01:13 AM
#7
JK Jedi Master
I had a similar sound. Turned out that one of the several welds on the heat shield for the exhaust crossover was broken. It's a difficult weld because of the thin metal, but that's all it took to stop the rattle.
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03-08-2018, 07:35 AM
#8
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Also, seems the noise is only present once engine is up to operating temp. That could be a sign that its not an exhaust weld.
03-11-2018, 05:00 AM
#9
From what you describe my '09 JKUR has had the same racket for some time now. Getting worse as time goes on. Found the usual crack on the crossover pipe heat shield and put a clamp on it. No change. Last weekend I resealed the oozing upper oil pan gasket. While the pan was off I checked the timing chain and discovered an alarming amount of slack. I'm now of the opinion the racket is the timing chain clattering. May be your problem.
