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Knocking and Popping From Under Car

M

mbenonis

NAXJA Forum User
Location
Charlottesville, VA
About two weeks ago my XJ decided to start making knocking and popping noises. It started off kind of soft and only on bumps, but has since progressed to loud knocks as well - sometimes it almost sounds like something about to fall off! The noises seem to be coming from the muffler/catalytic converter area, and occur more often when I go over bumps (even really small ones, though). Any thoughts on this problem?

FWIW, the noises started about the same time I got new shocks installed. I highly doubt there was any kind of intentional damage, though - we've been going to the same place for 8 years and have a very good relationship. The only problem is I'm now at college and 100 miles from home - thus I can't take it back there.

Thanks in advance for any insights!
 
90xj06 said:
and make sure the muffler is still mounted to the jeep.
Click to expand...

That could be the problem, the muffler hasn't fallen all the way off yet...

I would second checking the shocks, my bushings are shot and its making noise like you describe.
 
Sounds like the mechanic twisted off one of the upper shock bolts (common) and just put it back on with one bolt.
 
Well, we have our answer. Points to those who suspected a bad shock installation.

What happened, in fact, is that the tech who installed the new shocks used only one bolt. In addition, he used an airgun to tighten the bolt, and from what we could tell one misthreaded and did not fully tighten. As a result, the shock came completely detached from the underside of the body. The stress of having that one off caused the other rear shock to break its bolt and come off as well - so I was driving around with NO rear shocks! I had the problem fixed today, and stayed with this tech to make sure it was done right. Everything's now secure and the Jeep runs great.

I'm really shocked (no pun intended) that the first shock install was done so poorly - we've been going to the place that did it for over eight years with this car and have never had a single problem with their workmanship - they're usually top notch folks.

In other news, I also had the catalytic converter replaced today as well - that was the first diagnosis, and to be fair it was contributing to some of the noise as well. I inspected the old one and it had lots of rust going on in it.

Here's hoping that's the last repair for a long while!
 
mbenonis said:
Well, we have our answer. Points to those who suspected a bad shock installation.

What happened, in fact, is that the tech who installed the new shocks used only one bolt. In addition, he used an airgun to tighten the bolt, and from what we could tell one misthreaded and did not fully tighten. As a result, the shock came completely detached from the underside of the body. The stress of having that one off caused the other rear shock to break its bolt and come off as well - so I was driving around with NO rear shocks! I had the problem fixed today, and stayed with this tech to make sure it was done right. Everything's now secure and the Jeep runs great.

I'm really shocked (no pun intended) that the first shock install was done so poorly - we've been going to the place that did it for over eight years with this car and have never had a single problem with their workmanship - they're usually top notch folks.

In other news, I also had the catalytic converter replaced today as well - that was the first diagnosis, and to be fair it was contributing to some of the noise as well. I inspected the old one and it had lots of rust going on in it.

Here's hoping that's the last repair for a long while!
Click to expand...

Good to hear they took care of you and fixed the problem. Another reason why I do my own work, but I understand for some, that is not an option. Good luck on future repairs.
 
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