T1N Road Noise - How to fix?

I have a 2500 SHC 140" wheelbase T1N. Road noise is very bad.

I think the majority is from the cargo area, rear end etc. more than wind noise, engine etc.

Do you have an affordable method you recommend to reducing the Sprinter's road noise?

Thank you in advance.

I’ve got almost the same van (140” HRC) and issue... Obviously there is excellent sound transmission through the bare sheet metal, and I found that the panels are quite “lively” - especially where they have come loose from the frames (they usually float on sealant, which provides some deadening to the panel). Adding irregular mass to the sheet metal panels will help to deaden them and make them less resonant. I used an adhesive-backed butyl rubber roof underlayment product, selected on price and a high weight per square foot, and stuck on a layer with squares in a polka dot pattern. Tapping with your fingernail will tell you how you are doing on any given panel. I also used a 5/8” thick dimpled rubber livestock mat on the floor and over the wheel wells. The difference was noticeable. My spring project is to tackle the front doors and the floor area under the cab.

My neighbor is a sound engineer and gave me some guidance, but with all the glass we accepted that there would be a lot of sound coming in and concentrated on soaking it up. Soft surfaces like the futon, hammocks, and sleeping bags helped a lot!

-dave ;-)

If you can put a box stuffed with sound-deadening material around the wheel "humps", that will also help (as a starter).

Dave/Nautamaran's method is really the way to go.

(my Sprinter gets pleasantly quieter whenever the cargo area is sutffed full of stuff....)

Another recent thread sung the praises of wearing active noise-cancelling headphones....

--dick

If you don't mind the weight, horse stall mat covering the floor is quick and easy. Put 3/4" of closed cell foam under the front factory floor.

I had same problem,but 48 rolls of fiberglass insulation sorted it.Quiet as a mouse .

lofty whiteley said:

I had same problem,but 48 rolls of fiberglass insulation sorted it.Quiet as a mouse .

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Haha! (where’s the “like” button when you need it!)

I have built out my van with insulated ceiling walls and floor but for road noise what did the most difference by far was... insulating the front doors.
I just cut pieces of duct insulation and stuck in to the inside of the doors. Night and day difference!

Sent from my SM-N920T using Tapatalk

A stock Sprinter van is a big tin drum.

Horse stall mats made Frito sound like a Merc. Mass is your friend, as is de-doupling the flooring mass from the floor.

Here's how I did it. Long thread, but sound deadening is in there.

https://sprinter-source.com/forum/showthread.php?t=14166&highlight=Frito's+Bulkhead

IM not insulated so i feel your pain, fwiw tires make a difference. With nice Michelin all seasons the ride is much quieter, the Michelin winter tires increase the noise a lot

I second the call for doing the front doors. It made the second biggest single change in noise level for me. To give you an idea, the biggest change was installing 10mm thick solid rubber floor mats over the entire floor of the van. Thats about 100kg of rubber. The front doors took maybe 5kg of butyl sound deadening and is very easy to do. And as a bonus, it sounds like a Rolls Royce now when you slam the doors.

Do you have a plywood floor? When I took out my plywood floor it was very noisy. I put in 1/2 of Rmax insulation under the plywood and it make difference, while maintaining maximum head height. Then spray foaming in 1" foamular panels helped a lot too. The rest of the road noise for me is just the doors squeaking from bad adjustment and lack of grease, and the doors need to be insulated.

Stuffing the A and B pillars will help too. Putting rigid foam under the factory floor is a good option as well.

Midwestdrifter said:

Stuffing the A and B pillars will help to. Putting rigid foam under the factory floor is a good option as well.

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Especially the B pillar, which is right beside your left ear.

First, thank you everyone for your helpful replies!

When I got the van it had a plywood floor that was coated in rubber/bedliner. I wanted to gain maximum headroom and also be sure the floor was not rusting beneath the plywood so I removed it.
The wheel "humps" are still coated pretty good in a rubberized bedliner type product. Perhaps a box around them would help more.
I keep household padding and carpet on the floor but it doesn't do enough.
Perhaps the rubber horse mat will help more or doing something to keep the walls from rattling. Mine is a cargo van, no windows in the back except for the side door but it does have the grey cardboard type panels on the walls in the back. Maybe I should remove these and remount with foam or that audio sound stuff behind them? The stuff that's silver shiny on one side and black sticky on the other?

I would've guessed the majority of the noise was coming from the back. It is noticeably quieter when full of furniture etc. in the back but maybe it would be worth taking the door panels off and putting the same shiny/sticky audio sound stuff on them?

Am I missing anything?

anythingcomputerrelated said:

that audio sound stuff behind them? The stuff that's silver shiny on one side and black sticky on the other?

Click to expand...

Many will disagree with me, but my tests with "Dynamat" (that audio stuff) proved it less than successful at mitigating noise in my Sprinter. It's not nearly heavy enough.
They say it "damps vibrations". I think it does a better job at damping wallets.

When I rap my knuckles on the outside of Frito, it makes a dull thud. Mass is what it takes to block sound. Lead is ideal, but it's poisonous and expensive. Dense rubber matting is nearly as good and really cheap. Also, research "mass loaded vinyl".

Soft stuff like furniture absorbs what sound does make it inside. Try a load of fiberglass insulation if you want to hear a quiet Sprinter.

Dense, heavy boxes around the wheel wells really help combat road noise.

Also, remember that weight only costs gas when you're accelerating (or brake shoes when you're decelerating). At a constant speed, weight is mostly irrelevant to fuel use.

As I did my build-out I noted incremental improvements.
The most noticeable were when I boxed the wheel wells and when I treated and filled the bottom cavities of the wall structure. These made the most noticeable change in road noise. My research also pointed to mass loaded vinyl, but I balked at the cost and went with a dense roofing membrane to deaden my panel segments. This reduced resonance, not transmission.
To attenuate the transmission of sound energy through a panel, the surface needs to be heavy, and will function best if “decoupled” from the structure by a layer of resilient foam. This is when we looked at the high proportion of rigidly mounted glass and determined we’d get further soaking up sound rather than trying to further block its entry. A queen-sized cotton futon and the pair of canvas hammocks above dropped the sound level considerably.

-dave