My 89 4runner is a lot of fun to drive, but at freeway speeds (yes, the 22re is capable of freeway speeds!!) it is little noisy from the rear part of the truck.  

I'm sure it has something to do with the paper thin metal above the rear wheels.  What can I do to quiet the vehicle down?  Pull the interior panels back off and spray the fender wells with something?

Ideas?  Thanks.

vmax84

Baffled tires?

Pull all of the seat and carpeting out and coat the floor with a noise barrier like dynamat. I believe the self install rubber coating for truck beds will serve the same purpose and cost less. The dirty truth is that carpet alone isn't a very good noise reducer, that's one reason why home carpet has the padding under it.

www.dynamat.com/
www.linex.com/Primary/Products.aspx
www.smithsultimate.com/html/index.php
www.rhinolinings.com/

Also you might pull all the interior trim and fill all the areas between the outer skin and the reinforcing structure with spray foam. You can also undercoat the vehicle, that will help some.

The auto makers have devoted endless time and resources to solving this problem in the cheapest, most reliable manner. Their solutions:

1. Cover any interior metal surfaces that have one side exposed to the exterior with jute-backed matting (i.e., carpet padding).

2. Stuff any compartments formed by two metal walls with foam rubber (acrylic pillow stuffing also works well).

try differnt tires.

Depends on what the noise is coming from.  Assuming everything is in working order (not a bearing going bad, sticky caliper / ebrake shoe, proper alignment, etc) there are a few things you can do.

Replace your tires and make sure they are properly inflated.  Rotate them frequently.  This is the number one source of "road noise" on vehicles without an impending repair.  It's harder to find truck/suv tires that are as quiet as car tires but you can, as long as you plan to keep it on-road.

Dynamat is not sound insulation, it reduces rattle by making the panels you apply it to heavier so they don't vibrate as easily.  It will do a little for sound deadening in general just due to the mass, but that isn't how it is designed to work.  It's also no different from generic polymeric mastic (rubberized asphalt) which is much cheaper.  A layer or two in the wheel wells would probably reduce tire noise reasonably inside the cabin.

A good coating of some kind of mineral wool like fiberglass would do a better job than dynamat for sound absorption.

Crank the tunes.

Tire tread pattern, window & shell gaskets/seals and what kind of condition/where does the exhaust exit (think droning).

Brian

Quoted: Pull all of the seat and carpeting out and coat the floor with a noise barrier like dynamat. I believe the self install rubber coating for truck beds will serve the same purpose and cost less. The dirty truth is that carpet alone isn't a very good noise reducer, that's one reason why home carpet has the padding under it. www.dynamat.com/ www.linex.com/Primary/Products.aspx www.smithsultimate.com/html/index.php www.rhinolinings.com/

He has the right idea, but you should also use LMV (Limp Mass Vinyl) on the flat surface.  It's heavy - 1 lb. per square foot - and damps sound very well.  Check out www.soundproofing.org

Take care buddy, good to see you posting.

Thanks for the responses.  I had the 4runner down to my buddies garage to balance the tires.  He did look at the tires and said "vmax, you need to throw some more money at it........these tires are crap".  Me says "gas station guy best friend, you're just trying to sell me some tires"........In all honesty, they are getting pretty close to replacing, and they are weather checked pretty bad.  Lots of cracks in them.  

So, it's probably a combination of all the above.  Old tires, weather cracked, maybe a little bit of cupping (or whatever you call it), and old crushed beer cans for fender wells.

Nice thing about having kids that get all A's in school........they pick up on what you're saying pretty quick.  I mentioned to my oldest kid that it takes a lot of money to keep vehicles on the road, so she grabbed a couple bucks out of her pocket and said "here's my contribution".  Without even having to go into much explanation, I think she has already grasped the "pay to ride" theory.  Now, if I can just get that point across to the younger one I'll have it made.  

Thanks a lot.

vmax84

Scrub your wheelwells clean and spray in the rubberized undercoat spray.
Made a difference in my Camry.

I've heard that running Polyurethane in the weather stripping on all the doors/trunk/etc helps too.  You actually run the tubing inside the weatherstripping.  

Quoted: Pull all of the seat and carpeting out and coat the floor with a noise barrier like dynamat. I believe the self install rubber coating for truck beds will serve the same purpose and cost less. The dirty truth is that carpet alone isn't a very good noise reducer, that's one reason why home carpet has the padding under it. www.dynamat.com/ www.linex.com/Primary/Products.aspx www.smithsultimate.com/html/index.php www.rhinolinings.com/

Theres more affordable options like Brown Bread, E-Dead, etc.. in the sound dampening arena. They can be painted on or applied in foil-backed adhesive sheets. I use a combo of both.

The other thing, besides deadener/dampening, is that some tires are just god awful loud... you might look into your tire make/model to see what people say about the road noise.

Dampener is going to run into the hundreds of dollars, and it does take some work.... because only covering select spots won't do much good... so often times if you're just looking for a quieter ride, new tires can be the cheap fix.

Man up.

Quoted: try differnt tires.

This is, by far, your biggest culprit. Agressive tire and noise are like liberals and gun control, they always go together. Sympathetic vibrationand resonance is another biggie and wind noise is also.

You really need to approach it from several different angles, it'll never be a quiet truck but you can cut down on the annoying harmonics like tire whine, and boom with some non absorbant insulation, especially on the floor and wheelwells.

Gotta go look at a FJ 40 today I saw for sale yesterday, hopefully it's not a rust box, it looked OK from the road.

I have 2 layers  on the floors, firewalls with three layers of Ensolite.   The doors got 5 layers plus 2 layers of Ensolite.

At 80mph it sounds like I'm doing about 40.   Noise was cut by 75%

http://www.raamaudio.com/cgi-bin/index.cgi


Well worth it.

I've got superswampers on the Jeep.  If I'm going further than a few miles, I'll use earplugs.

Thanks a lot for the responses.  I'll have to count my ride contributions and see what I can afford.  

Thanks again.

vmax84