Hi,
I am going to be working over the next several months to reduce noise in my Cherokee. I wanted to record my efforts here for any others that are looking to do this. I'd also be happy to get any ideas from others.

I am suffering from tinnitus (ear ringing) from my time in the military. My hearing is just fine--it's the ringing in my right ear that drives me crazy. I need to be able to hear my little boy in the back seat too, so I am eager to cut down the noise.

I am going to be looking to reduce noise from every aspect of the Jeep and I am willing to throw some money at this because I think I can make a big difference with a little effort. This is my 3rd Cherokee, so I'm reasonably handy with them.

Here's my current setup: 2001 Cherokee 4wd, 4.0L stock all the way around with 145K miles. There is no hoodliner material in this Cherokee.

The first thing I did was buy a decibel meter to start tracking the actual noise inside the Jeep when idling and at speed.

I am showing about 63dbA when I'm at 55 mph on a reasonably calm day (little wind). When I get up to 70 mph, I hit about 72dbA.

Some things I have noticed so far since I've had the decibel meter. The mechanical clutch fan makes a huge amount of noise. When accelerating, that clutch fan adds about 10 dbA of noise.

In fact the engine makes a huge amount of the noise that I am measuring. I had originally thought that the road noise/suspension/tires would be a major culprit, but the engine noise seems to be a real problem.

Going over any seams in the road or bumps always gives me about a 6-7 dBA gain in noise too.

I am looking to purchase an electric fan replacement for the mechanical clutch fan setup. I am likely also going to a 180 tstat to help out the electrical fan. I suspect this will have a big difference in the noise when accelerating and when idling at the stop light.

After that, I am considering purchasing a hoodliner and sound absorption material for the firewall. I think once I get the engine noise reduced, I should be able to focus more on the tires/suspension and body noise. Thanks for any help and a special shout out to any tinnitus sufferers!

 

Stop driving it and turn the motor off. All Cherokee noise will be gone.

Seriously, though, there are a few threads covering this here, and if I remember correctly there isn't too much you can do.

The XJ is pretty much a brick on wheels, unless you majorly improve the aerodynamics, you will never rid yourself of the wind noise.


I will try and search when I have time, see if I can find the other threads. I will post links, hopefully you will find useful info.

 

I "hear" what you are saying about aerodynamics, but Land Rovers are awfully quiet and they have basically the same shape.

I should also mention that I have measured the noise from the headliner/roof.

When I place the meter up by the roof, I see a huge jump of about 5 dbA when the meter is a few inches away. There is no sound dampener up there and that's another spot to consider.

The body itself is a poor insulator of sound, but I gotta think there are things that can be done to cut the noise down.

I've seen some other threads about stereos and dynamat, but I am looking to cut all the noise down for my ear.

One other thing newer cars have is a vinyl layer on the windshield itself to reduce noise. I am not sure if this could be applied in an aftermarket product, but it is supposed to make a big difference in wind noise.

 

i would check out lizard skin sound deadening. this stuff works great from what i have heard. they had an episode on i thinks TRUCKS that they used in on the inside of a big pickup and it worked great. i can barley hear the person next to me when doing 65-70 mph because my doors dont seal all the way and i have no carpet and loud exhaust so it sucks at points

 

more speakers and louder volume

 

Dyno-mat the roof between the head liner works great i also rhino-lined (professional) my headliner

 

I put an extra layer of automotive sound/temp padding ($20 a roll at Pep Boys) under the carpet in the cargo area and I glued padding inside the rear quarter panels around the wheel well up to the back side windows, and under the cover of the tailgate. Brought my decibles down by 5db. Not enough. I want to add padding under the rear seat, the doors, headliner and under the rest of the carpet if I ever get some free time.

 

True, but you can buy multiple XJ's for what you pay for one Land Rover. Plus the XJ looks better, noise and all.
Keep us posted if you get it quiet inside. Someone may want to buy and patent that process. Probably be able to retiire in a week or so.

 

Sup chrisl757..I know how it is dude. Having perfectly good hearing when i went in to being "medically deaf" when i came out. If you want to make your truck a little quieter, you can install "dynomat" type material in your truck under the panels/carpet/doors/cab-side firewall. One good product i have used with similar property as dynomat is available at Home Depot: http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053

same $hit but at a fraction of the price as dynomat. I have used them in my trunk, home made sub box and it works!

Another thing that bugs me is when I open/crack the windows..install these: http://www.jcwhitney.com/dark-tint-i...d=d1163y2001j1

Get less aggressive all season tires.

I hope that helps you out.

 

Wow guess I should read more than just the title... I feel like an ***!

Let me start by saying sorry, & thanks for serving our country!

For sound deadening I would also dynomat the hood, replace the hood, & door seals! The roof also generates a lot of wind noise, so dynomating under the headliner would help a ton.

Again sorry for skimming threw, & for my original post...

 

You can turn off the motor in a Cherokee and coast downhill and it is still a noisy ride.

I know because when I lost a CPS I was 3/4 mile from my house, luckily it was all pretty much downhill from where I was.

I coasted to my front door.

 

 

Rip out everything, use poor man's dynomat which is "Peel and Seal", lay a plastic vapor barrior over that and you will substantially reduce niose. Here is us doing the floor, but do the floor, doors, roof, and hatch:

http://www.lowes.com/pd_154017-81326...seal&facetInfo=

 

4 brand new pioneer speakers and 2 kicker 12'' comp VR's did the trick for me

 

Wow, seriously? I can't believe this thread. Way to fail guys. A guy with a medical condition - which he got in service of your country - who loves his XJ asks how he can reduce noise so he can hear his son and you post crap like "buy a Prius" and "get a bigger stereo? I'm not sure if this is illiteracy or idiocy. You should be ashamed... no respect at all.

I'm not sure on advice that would be specific to an XJ as I'm still learning, but with general sound proofing concepts, most of the noise is going to be cracks or channels that let in air (wind turbulence) or vibrations in the vehicle itself that get louder through non-rigid panels, such as the body. One common approach is to add mass to those panels, such as heavy rubber padding, which makes them harder to vibrate and changes the sort of noise they can give off. This is a great idea for the floor. Rip up the carpet, slap some soft rubber undercoating in there, and set up some heavy deadening material like that DynoMat stuff, then stuff the carpet back on. Consider doing this anywhere there's a panel that can vibrate... roof like you noticed is a pretty large panel that amplifies many vibrations due to its surface area. Another is insulation, which absorbs the vibrations in the air within a given space. Stuff the doors and behind the headliner. Beyond that you'd need to tackle the source of noise like the drivetrain, etc.

Have fun!