# soundproofing engines



## coolasluck (Apr 26, 2013)

I have also been looking out of intrest as my coach can get a bit noisy,and i would imagine could do your head in over long drives so was looking into ways of sound proofing the cockpit,as its a coach the engine is obviously inside and inbetween pasenger and driver ,just came across this:



Reduce engine noise with our Acoustic Blankets - Car Engine Soundproofing



I wondered if anyone had any experiance of this and does it work,it just sounded to me like a bit of a gimick.


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## GRWXJR (Apr 26, 2013)

I've used acoustic sound deadening pads and acoustic blanket to reduce the noise in my LDV Convoy from the engine. 

I've put my materials in the dash, on the floor and under the bonnet / engine bay. It has made a useful improvement. 

This link is trying to achieve the reduction by tackling 2 areas I'd guess - resonance of the engine cover and foam to damp airborne noise.

This looks like its pricey but it could well be effective. I'd ask what sound pressure reduction that you could expect. Every 3dBA is halving the preceding noise level (my attempt dropped the measured noise by over 6dBA btw). 

Sound pressure readings aren't the whole story (as frequencies & perceived noise is a factor). My van was too loud and intrusive before & now it's a lot more tolerable, so it is possible. 

You might well find that some noise shielding under the engine cover as well as extra blanket on top of the engine cover helps.


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## Deleted member 967 (Apr 27, 2013)

Hi Cool

We went to Noise Killer in 2008 and they fitted the blanket material under the carpets in the cab and on the dash area behind the windscreen on out Hymer S700.
They also fitted the engine blanket.  This made a big difference to the in vehicle noise from the engine. 

Make sure engine blanket is firmly attached.  Ours was disturbed by the garage in Spain and we spent ages looking for a burning plastic smell.  The blanket had slipped onto the exhause manifold.  It melted the edge slightly but that was all.

Noise Killer also glued the material under the bonnet cover inside the vehicle.  This glue became unstuck last summer in the constant damp conditions when we were parked in the lakes on grass.  The material slid down and lodged itself between the engine and the body.  Some of it went down past the exhaust manifold.  The worst was the bit that slid down and got caught up in the fanbelt.  This initialy caused fan belt damage and involved a recovery in the south lakes as the work could not be done on the roadside.   We thought we had it all sorted before we headed for Spain for the winter.  The garage told us they had checked the pulley alignment and it was OK.  They had fitted a new fanbelt fensioner, shocker and spring assembly the year before, so it was in their interest as it could have been a guarantee issue.  They showed me the Noise Killer material that they had fished from around the tensioner mechanism.

At Folkstone we heard another noise under the bonnet and on checking another piece had again gone through the fan.  We got it out and all seemed well.   

I was touring in the mountains around Teruel in Spain when a noise developed.  We and a garage at Torrevieja could not find the soure.  We continued our trip but the noise was getting worse.  Near Almerina there was a nasty noise under the bonnet and the generator light came on.  I stopped and found the fan belt still in place but the tensioner pully had totally disintegrated.   

This resulted in another recovery.  The garage replaced the pully and the fanbelt.  We set off again and we had a slapping noise when we got to 80k (50mph) on the motorway.

We returned to the garage and they had to strip out the radiator to get a good look at everything.  The fanbelt tensioner had suffered damage as had the idler pulley.   The tensioner spring was distorted.   They fitted a new tensioner,  tensioner shoc k absorber and idler pulley.  The fitter however fitted the old spring as the Merc dealer we were at didn't have a replacement in stock.   This damage we think had beed caused by the Noise Killer material being caught up in the fan mechanism.

I contacted Steve at Noisekiller with this information, but he never bothered to reply.

Our vehicle is now booked in for a new fanbelt tensioner spring on Tuesday.   We limped round the rest of Spain, through Portugal and back through France back to the NE of the UK.

We were limited to 30kph in second 50kph in Third 70kph in fourth and 80kph in fifth.  Exceeding these speeds there was the slapping noise from the fan belt.

We can definitely recommend the breakdown cover provided through RAC commercial on a Comfort policy.

We had good results from the Noise Killer, but it was the constant damp last summer that we consider caused the glue they used to fail.

John


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## Deadsfo (Apr 27, 2013)

Dense materials are what is required ,the ideal being thin guage sheet lead encapsulated between some tough fire proof marerial made up into the shapes you rerquire and fixed a bit more permanently than the job done on tyhe previous post. you can also use flash band on the floors and around the dash ,it has a bichumin type backing and a quick blow over with a hairdrier will fix it ,as well as absorbing  noise it will stop noise that emanates from the sheet metal vibration by putting it in strips on the inside walls in the case of a panel van conversion  ,I'm not sure how it would behave in very hot climes in so far as wether the bichumin backing would become softer and subsequently runnier ,but it is waterproof and would give the floor the added protection from rotting from the inside out due to moisture under carpets that never seems to dry out.


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## Mastodon (Apr 27, 2013)

I fitted a noisekiller kit to our Trooper. Not difficult to fit as all the parts were pre cut. Make a substantial difference to the cab noise ( cab and engine kit). Looking at fitting it into our Master. Price had gone up in the last 10 years (!)   so I priced up the materials, you could probably save a few quid if you knew exactly what you were doing and were prepared to cut it (no easy task) yourself. Guess what- I'd rather someone else did all the guesswork... Not paying £100 to get it fitted though.


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## coolasluck (Apr 27, 2013)

The firm i posted the link to is in royton which is where the father in law lives so may well give it a try.


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## Deleted member 967 (Apr 27, 2013)

[No message]


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## coolasluck (Apr 27, 2013)

We had the pesky little critters in our van this year as we put it in storage on a farm.
They stunk the place out made a mess but i dont think they caused any damage.
That water has left a bit of a mess there hasnt it.


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## Deleted member 967 (Apr 27, 2013)

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## Deleted member 967 (Apr 27, 2013)

Not on this old Merc.  She is as dry as a bone and uses no oil in 12 months between oil changer at service.

John


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## GRWXJR (Apr 28, 2013)

*Rads & rad caps*

Re rad caps. These age and the seals don't work as well, while the spring pressure can fade too. The result is that it can't contain the coolant at peak operating temps. 

If the coolant hasn't been changed as it should the matrix can block too. We see this in work regularly - cooling system probs on large stand y engines of a certain age are common. 

Rad caps tend to come in fixed sizes and with a narrow range of pressure rating. Chances are that decent radiator repair firm will stock caps to fit in different pressures. They'd probably be able to work out what's the right rating for your engine as well

If stuck then chances are my firms suppliers could help with stuff like that


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## GRWXJR (Apr 28, 2013)

*Acoustic Foam*

Acoustic material is big bucks. I'm working on a project with a supplier to refurbish 20 gens with new acoustic canopies. 

If it comes off I'm going to see if they'd supply me with some of the acoustic foam they line the canopies with - typically 30mm dense foam that does a great job of attenuation of big ind diesel motors. 

Dunno if I can get some yet or for how much but gotta be worth a try.


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