Insulating exhaust noise

[Tom W]

I decided to try to insulation to reduce the exhaust noise ( drone ). I just removed the seats and carpeting and discovered that the right side of the carpet was soaking wet underneath, all the way from the front to the rear. I have been thinking that the noise has been getting louder and I think this might be the cause. I have not had a chance to find the leak yet, I plan to get inside and have someone use a garden hose to see if I can see where it's leaking. Assuming I find the leak and get all the carpet dry I am going to put in extra insulation or undercoating on the floor and back of the cab. After that I will wrap the exhaust system with thermowrap and clamps about every foot.
How does this plan sound? Any suggestions? Any ideas about the leak?
Thanks, Tom

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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.

 

[Steve St.Laurent]

The most likely source for the leak is the 3rd brake light.

-Steve

 

[Lordsman]

Could be the A/C evaporator condensate drain. Have you modified it so the water will drain out the drain instead of into your truck?


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99 2500SLT,QC,4x4,6-spd,3. 5 lsd,LB,Camper group ,Rhino liner,Airlift 5000 airbags,Redline hitch,Tekonsha brake control,Diamomd plate bed rails,Dodge grill & splash guards.

 

[Tom W]

Yeah, I'll bet it's the AC drain, it's coming from the front, I'll check it tomorrow, I'm too beat tonight, played golf all day and then ripped out the seats and carpet. I have a fan blowing on the carpet and have only the drivers seat put back in. It's pretty loud with no carpet but not as bad as I expected. Thanks for the tip.
Tom
Lordsman, I just reread your note, is there a mod for this?

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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.

[This message has been edited by Tom W (edited 02-21-2001). ]

[This message has been edited by Tom W (edited 02-21-2001). ]

 

[Lordsman]

Tom,
If you want you can research older threads where there are complaints about a musty smell/odor from truck duct vents. I clamped
a 5/8" I. D. vinyl(clear) tube onto my drain
fitting and tied the end of it off with a plastic tie on my brake line on right front.
Now I see it draining properly at the wheel well. The problem is the drain faces straight toward the front,the air blows right into it when you drive pushing the water into the cab. You can get these parts at a hardware store. Drain is at firewall behind the air filter housing and directly under what looks like the a/c suction line accumulator. Easy fix.

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99 2500SLT,QC,4x4,6-spd,3. 5 lsd,LB,Camper group ,Rhino liner,Airlift 5000 airbags,Redline hitch,Tekonsha brake control,Diamomd plate bed rails,Dodge grill & splash guards.

 

[RKohn]

Whoever came up with the stupid idea of carpeting the floor of a truck anyway?
Musta been some dumba$$ marketing bozos.

Anybody plan on driving barefoot? Oooh, I'll buy a Dodge cause that carpet feels so good.

It's really so they can sell you some overpriced ugly rubber floormats to cover the carpet, that cost you far more than what it's worth, that should have been rubber floormats anyway, that you already ruined with your dirty greasy feet the first time you fueled up at the truckstop.

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Y2K Red Stealth Sport 2500 4X4 QC SLT+, 5-spd, 3. 54 anti-spin, 265-75-16 LTX’s (There ain’t no such thing as options, cause ya gotta have it all, including: DC’s dead cow/vinyl interior and don’t stop anti-lock brakes. ) Stock, but not for long. Oops, too late. What silencer ring? (More fun than my 98 SST)

[This message has been edited by RKohn (edited 02-21-2001). ]

 

[Deezal Man]

If I were a bet'n man, the water soaked insulation should actually improve sound dampening... not make things louder. That is unless the water disintegrated the insulation. Sounds like your on the right track. That spray on sound deaden'r stuff really works well, but its not cheap. It does make a difference. Another cheap way to insulate sound is to use regular old fiberglass house insulation between the inside and outside panels. Only problem is, you can't do this to the front doors... . and the RAM doesn't have much else. This ideal works well in hatchback cars that have a lot of inside plastic panels.

I agree with the idea to check the A/C drain.


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98. 5' 24v 2500 Auto/3. 54 4x4 SB QC 285-75-16's on Alcoa's. Everything but leather. PIAA 1200's, AMSOIL dual filter relocation system, Smittybuilt Stainless Steel Nerfs, Rhino Liner(Junk), K&N air filter(For Sale)15 year AMSOIL dealer. Time permitting, Soon to include Ultra-lite Pyro,0-50lbs boost, Trans temp in the pillar. Rancho 9000's with in cab adjustment.

 

[Cooker]

Dynamat is excellent at stopping unwanted sound from entering the cab. The true dynamat is pricey, but I purchase a Dynamat knockoff (looks the same, same texture, same thikness) from a home audio supply store here in my town. I think they charge $5 for a sheet (18"x36") vs. $20 - $30 for Dynamat.

Dynamat is also very thin so it generally doesn't affect how well the carpet molds to the floor.

Another waterproof option would be to have the interior "Rhino-Coated". I've been thinking about this for a while, and may decide to do it sometime this summer.

 

[BigMo]

RE: Water leak - - I second Steve's guess. My `98 QC leaked around the 3rd brake light. Solution was clear bathroom caulking.

I look forward to reading how to better insulate the interior from noise.

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BigMo: 2001. 5 SWB 2500 ETH/DEE, 4x2, Flame Red/Agate SLT, LSD, 5th wheel slider hitch, Linex bedliner.

 

[Tom W]

I got my truck back together. I put a hose on the AC drain, should fix the leak. I checked out Dynamat, looks like a good product but cost prohibitive, close to $9. 00 sq ft, and I couldn't find any cheaper knock off. I got some heavy 1/2" carpet pad and lined the floor and back panel, I used 3M spray adhesive to hold it place. I also got a can of "Great Stuff" expanding foam and filled some of the hollow spaces, like the one just below the rear window. It was not a particularly difficult job, just a lot of screws and bolts. The center console and seatbelts are all hooked together and a little tricky.
The results are a noticible reduction in exhaust and road noise. Dynamat would probable be better but this cost less than #30. 00.
I talked to Banks and they are sending me a new muffler and tail pipe. The muffler is for a 12v, has a 4" inlet and 3" outlet and is an offset desigh rather than straight thru. I'll miss the 4" tip. Banks is covering all costs including return shipping, I am providing the labor. This tells me Banks is concerned about customer satisfaction, I couldn't ask for more. I'll report on the results later.


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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.

 

[QRTRHRS]

Somewhere, perhaps in the service manual or in the forums, I read about pressurizing the cab to find leaks. Close the windows, turn the fan on full and use soapy water on suspect areas such as the third light. I never tried this but it sounds like a good idea. I have used both high pressure and high volumns of water looking for leaks and was not successful.

 

[John]

Tom W, I used to have the 4" inlet/3. 5" outlet, galvenized Banks Dynaflow (chambered) muffler and 3. 5" diameter tailpipe on my Ram (BTW, this is a 12v setup) before they offered the 4" diameter stainless steel exhaust system (which I have now). The Banks 3. 5" diameter (mandrel bent, galvenized steel) tailpipe has a polished 4" diameter stainless steel tip welded on (whereas a 4. 5" polished stainless steel tip is used on the 4" stainless steel system). BTW, the chambered Dynaflow muffler has a real pleasant, throaty sound to it without the droan. I'm sure you will like it. #ad
Adaptation of the two different systems may not be a real fun project (due to the inlet/outlet offset of the chambered muffler)... I know this as The PowerShop (Enumclaw, WA) made this retro enhancement on a customers Ram.

If you are going to install thermal wrap on your exhaust system you only need the special clamps at each end of the wrap. Additionally, after you have applied the wrap you will need to spray on their special coating to keep the wrap from rotting or you can use spray paint (the latter tip was originally provided by Craig Scholl from the old CDW BB).

I also applied Dynamat Xtreme to my cowl, on the back cab wall (two layers) and in both front foot well areas (also two layers) of the cab (so far... I will tackle the doors this summer), adding Dynamat Hood Liner to the back cab wall in addition to the Dynamat Xtreme. BTW, Dynamat Xtreme provides four times the sound deadening ability of the original Dynamat. Very high quality stuff... but $$$$

I was wondering if you had your windshield replaced recently? With a water leak of that magnitude I would suspect the windshield or third brake light.

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John Treibel
'98. 5 2500 QC 4x4 Sport, Glasstite Vision II, 285 BFG A/Ts on M/T Challengers, Warn 4X Boards, Mopar fender flares & tow hooks, NW Custom s/s-rubber mud flaps and accs. , Mag-Hytec diff. cover & trans. pan, Edelbrock IAS shocks, Reese Titan V hitch, SPA gauges (3), Dynamat, '00 Sport grille and headlights/PIAA Super White bulbs, PIAA Dual Sport 900 aux. lights, BD exh. brake, Amsoil Dual Remote Bypass, Optima Yellow Tops, DD3s and DD TTPM, Aeroquip AQP braided s/s fuel hoses, Banks High-Ram intake manifold and 14 cm2 turbine housing w/Big Head wastegate actuator, ATS 3-piece exh. man. , Banks 4" dia. s/s exh. sys. , DTT 93% TC, DTT custom tuned VB, BD modified trans. front pump (enhanced by DTT), Air Bulldog induction hood (with NACA ducts), plus MANY other trick modifications

[This message has been edited by John (edited 02-24-2001). ]

 

[David_VT]

Having just done a clutch with Articat, I can tell you that a whole ton of noise is just waiting beneath the shifter (manual transmission). Make sure all that area is tight. I am considering if there is any value in packing the shifter boot with fiberglass.

Pressurize the cabin, I like that and will try it myself. maybe another excuse to add yet another boost gauge to the pillar #ad


[This message has been edited by David_VT (edited 02-25-2001). ]

 

[CCahill]

Pressurize the cab ?

You will remember to tape off the air exhaust vents, right?

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2001 Quad,4x4,4. 10LS,LB,Loaded,stock,... . 65 Chevelle sedan, Hella nice driver, 53 Nash Rambler Convt,1 of 653 built,[not a Metro], GM drivetrain, injection, and auto/od
Specialized FSR PRO Stumpjumper Cannondale F2000, Loaded
MTD Lawn tractor with flames
12' fishin' boat, loaded. .

 

[Tom W]

I'm quite sure the water was coming from the A/C drain, poor design or possibly just forgot to put a hose on it. Easy to put a piece of 5/8" plastic hose on it, I think that will take care of it but I'll let you know if it doesn't.
The extra padding under the carpet and the rear of the cab makes a considerable differance and I think it was worth the effort. I still have the resonance at 2200 RPM put not quite as loud and there is much less road noise.

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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.