Engine resonance

[TheMadhatter]

I am not sure if I have a problem or not I have just noticed something that I had not before and was wondering if it's normal and if anyone else has noticed this.

Around 1600 - 2000 rpm the engine not of my 130Tdi is quite "boomy" and the engine vibration is at it's worst. It's not particularly obtrusive in the front of the car. However the other day I sat in the back and got my long suffering Dad to drive me round so I could find the source of a rattle in the head lining.

This is when I noticed how bad this boom is if you sit in the back. It's loud and distracting and I would not like to travel far in the back of my car.

Is this normal for the 130 ? or is something some where amiss? Has anyone else noticed this?

I might just be nit picking but you know how it is ;)

[bobmac892]

Madhatter

Do you have both of the front engine covers on the underside of your car. When I first got my '03 TDI Estate the front cover was missing which caused the rear one to be blown down onto the road. Anyway a ******* replacement at £120, noticeable quietened the engine noise.

I was advised of the tow cover the front one is more important than the rear one and I was surprised the diference. The cover does have a lining of expanded foam to supress noise.

I know the fixings for these are a swine to re fix after work and are often not properly attached by garages. I had a bit of work done just prior to my one failing.

These are also available on eBay for alot less but the ones I saw (after being mugged at the *******) didn't have the foam lining.

Failing this I have noticed an echo when one the rear windows isn't fully up.

Hope this helps.

[TheMadhatter]

Both engine covers are there.

It's something I eihter suddenly noticed or its not been there before. When your sat in the back it's that sort of low frequency noise you get if you leave a window open. My instant reaction was that I might have a leak in the exhaust but there is no obvious signs of this from out side the car. It concides with any rattles I have as well (head restraints and that bloody bit of head lining) the engine is nice and smooth at idle or higher revs, could just be the cold weather and engine taking longer to warm up. I am going to try and monitor it I have 6 months left on the warranty.

[vincentbob]

This is quite possibly the air duct that connects to the air filter housing, its a common problem and always seems to make itself heard at the revs you mention.
I've had it with mine, and I have heard of several others.
The duct clips into place and in time becomes a loose fit; the cure is to hold it in position with some tape.
To test, get someone to hold the engine at the revs that make the noise, you can then hold the duct and see if its that.

[TheMadhatter]

That may be it. I have done this but its not the the box/vibrating on the rest of the car its the air resonating in the intake system.

There is some air escaping from the junctions and this is making a booming noise !. If I squeeze the ducks the noise changes. I will try and seal these and see if it makes a difference.

[TheMadhatter]

I tried the tape on inlet pipes trick but that had no effect. Just posted this on a similar thread, but for those who have helped me on this thread here it is as well


I will try the sponge trick tomorrow. I am just trying to work out if this a car trait or something dying. To aid this and nerdy as it is, here are the sounds my car is making.

In the front
http://www.madhatmtb.pwp.blueyonder.co.uk/mp3/MVI_2584.mp3

In the back

http://www.madhatmtb.pwp.blueyonder.co.uk/mp3/MVI_2585.mp3

From under car

http://www.madhatmtb.pwp.blueyonder.co.uk/mp3/MVI_2586.mp3

I will get one of it under load driving later. I want to have some idea of what it is rather than "just a booming noise"

[TheMadhatter]

I have done the sponge trick today and it has had no effect on the booming but has silenced a growling noise I got under heavy load.

One question for the techs though. The EGR valve, when is it supposed to operate/move. I was watching it and listening to the engine as some one else steadily increased the engine revs and then rapidly changed the revs and it never moved. I checked with the engine off and it moves freely by its self.

[stonedagain]

I had a similar growl/resonance on my Passat tdi 130. Tried the usual suspects eg intake ducting air filter, engine cover etc to no avail. On Sunday, I checked my pollen filter, & after refitting the cowl I went for a drive & immediately noticed the elusive growl had gone! When I got home, I had a look around under the bonnet to try to discover what I had done to kill the dreaded growl. When I examined the cowl, I noticed some marks on the battery cover & on the cowl, plus some matching marks on the underside of the bonnet. It looks like there is only a very small clearance between the bonnet & cowl, which can allow them to vibrate against each other at certain engine rpm if the cowl is not perfectly aligned, causing the dreaded growl. I fitted two short pieces of felt tape to the areas of the bonnet which were marked to prevent future problems. The car is now a lot quieter than it ever was.
Hope this helps others to kill their growl too!
:beerchug:

[TheMadhatter]

I will have a look at that to stop the growl. However the booming throaty noise is slowly getting worse so I strongly suspect one of my silencer/mufflers has gone. It looks like the original vw exhaust so after 80.0000 miles I would not be surprised. Its quite hard working out which bit though.

[TheMadhatter]

I had the centre silencer replaced to day and that has got rid of the growly noise I could hear, but has not had much effect on the booming.

Which is kind of what I expected one part of the noise sounded like the exhuast and the car is quieter now inside. However that booming noise has been getting worse over the last few weeks. You can feel the car vibrate. It's most noticeable if your on the motor way in 6th and you slow from 70, nice and smooth to 60 where you get the booming and vibration.

Anyone got any ideas ?

Between the water leaks, the begginings of an oil leak around the crankshaft oil seal and this exhaust my love affair with this car is slipping. Not quite how I expected my VW owner ship to go.

[Stevebt]

Hi

I have a similar problem with mine, I have noticed that the Inter cooler is Vibrating in its mountings, which are only rubber grommets, if you grab hold of it from the wheel arch the noise stops. As you need to take the bumper off to replace the grommets I will wait until I have some decent time off before I attempt a fix.

[TheMadhatter]

You can feel the vibration right through the car, it feels a lot "heavier" than the sort of vibration I would get from that. There is not much vibration though the gear lever or clutch pedal. It feels like an engine vibration and depends on the revs it's just more noticeable going from 70 - 60. Is there an easy way to check the engine mounts ?

[TheMadhatter]

Ok an update. I took the car to a VW specialist to get a qoute on replacing my now leaking the crank shaft oil seal. They had a listen to it and the mechanic thought that part of the centre silencer had been blown into the rear silencer, and that replacing that should cure the noise.

And
:biglaugh::beerchug:

That cured it. Noise levels are back to what they where when I bought the car. However this car was not going to let me fix it that easily:aargh4:

The new centre silence has now started rattling like a bag of bloody spanners. Give it a thump with the engine off and you can hear something rattling inside it. At idle it sounds like the above bag of spanners

Bill hooks

So back to the garage for them to fix that then...and put one that does not bloody RATTLE !

[TheMadhatter]

Garage replaced centre muffler under guarantee , booming noise back. so back to square one as they say.:confused: Any one have any idea *** is going on ? could it be the rubber exhaust mounts ?

This is really starting to get depressing

[FLIPKEY]

Did this specialist garage fit a GENUINE VW part or was it a copy ????

[TheMadhatter]

No I have had Bosal replacements which look identical to the original vw ones, vw wanted £220 for each silencer !!!!.

My local non specialist ( well they do seats work for them) changed the centre silencer which was shot. Noise got better but did not go away. Then when I was getting a quote for the oil leak at the local independent VW garage I mentioned the noise. He had a good look and showed me how the rear was also rattling and that the gas flow was less than it should be at idle. Was advised that having the rear silencer replaced should cure it.

So I had the rear replaced and Bingo noise stopped.

Then the new middle one started to rattle. Took the car back and they swapped it for another Bosal one and on the drive home the booming was back.

I am totally confused :mad:. If the new rear had been blocked by the failing new middle silencer it would have been booming before the change? and not just after. So I am assuming that the new rear box is al right.

The only thing that I can think of at the moment is that its some strange exhaust vibration being transmitted into the cabin through the mounts, or the replacement middle box is faulty as well, which would be very strange. The shot exhuast was vibrating and causing it, and in some way the new one is doing the same. I am going to try changing the rubber mounts and maybe giving it a twist.

After that I am suspecting one or both engine mounts are on the way out and that is causing vibration in the exhuast.

Frankly I am "exhausted" by all this, my once smooth quite car sounds like a chav's car on the inside at the moment between 1600-2000rpm. And having had the noise go away and come back is just :aargh4:

[deano-1000]

Hi TheMadhatter, ref your egr valve, I was under the impression that my egr valve was faulty too, looked at it with engine running ect, couldn't see it moving, then followed all the pipe work, looked in a manual and found the bit I was looking at, the lever that opperates the butterfly, only opperates when you turn the car off, it stops air from entering the bores when engine is switched off. The egr valve itself is inside the casting and cannot be seen unless you take off the air duct. This valve is opperated by the vacuum pump thing that sits on top.

[TheMadhatter]

Thank's for that I had seen it moving when turning the engine off, that will be why then. I am gonna take the car back to garrage who have been doing the exhuasts and see what they think.

[FLIPKEY]

I had the same fault on my 130 sport, vibrations at 1900 rpm then no vibrations at 2000rpm got quite noisy in the end, When I held the tail pipe while someone held the revs at 1900rpm the vibrating stopped, I was told the exhaust was shot by three separate garages, the last garage said live with it or spend 600quid a new OEM exhaust, I decided to part company with veedub.

When you find the problem I recon there will be alot of happy passat drivers
good luck.

[TheMadhatter]

Including me.

Being logical about this, it was fine until the "new" middle box was changed. So taking it back to see what the garage think.

When i bought the car in June it was not doing this, and only started since xmas. Last week it was cured so it has got to be something to do with the exhaust or the way its mounted, or the new box is faulty. Will see tomorrow.

[TheMadhatter]

Went to the garage earlier got it up on the ramp and ran the engine at the resonance speed.

The whole exhaust is vibrating at 1800rpm. When they held the rubber mounts the booming stopped in the cabin. So they are going to renew these and see if that cures it, and try adjusting the way the exhaust is mounted

And if its not that it's the flex joint or the engine mounts.

[VWPhil]

Madhatter, did you discover the source of the resonance?

I've got the same problem and had the centre box changed which helped but didn't totally stop the resonance. It's going in to a specialist next week so I would like to give them some pointers if I can.

[VWPhil]

Madhatter, did you discover the source of the resonance?

I've got the same problem and had the centre box changed which helped but didn't totally stop the resonance. It's going in to a specialist next week so I would like to give them some pointers if I can.


...and now with my signature now that I've saved it - doh!

[TheMadhatter]

Err in a word no.

The mounts only improved things slightly. And I am not happy with the clearance between body work and exhaust in some places. So took it to the VW independent and they test drove the car. They are going to try re-mounting the exhaust as it kind of points to this being a factor.

The er bit is because they said it's not so much a fault but a trait with these, 1800rpm is the resonance frequency of the engine, and that I should really be driving around 2500rpm. Still they acknowledged that is was a bad one and maybe adjusting the exhaust might help. But the suggestion was I should have fitted the genuine exhaust to get it the quietest.

I am hopeful as changing part of the exhaust has greatly improved things once already. And if there is another fault that it should be left to develop for a bit as at the moment there is nothing that stands out

[xpro]

i have the same problem.At 1800rpm engine is resonanting like mad.I had the car on the ramp,checked all the brackets,mounts and all fine but noise still seems to be coming from the exhaust.it must be a common fault so?

[siman05]

any news guys? i have the same issue also. Had a new centre section (genuine) new DMF, new exhaust mounts, engine mounts.... and still the issue persists... to be frank im getting pretty exasperated with the whole thing....

[VWPhil]

In my case it was the replacement (genuine) centre box that was at fault. A further replacement (free) did the trick although the resonance is still there but at an acceptable low level. I'm putting this down to being a "feature" of the car.

[macquatic]

I'm putting this down to being a "feature" of the car.
Yes, same here.
Bought my 130SE in May and was the first thing I noticed, fiddled with everything listed above and decided to live with it (ain't spending a fortune on genuine exhaust)
So used to it now, I didn't even notice it until this thread was resurrected. LOL

[A Tdi]

It appears that i have similar 'booming' type sound but between 2 & 2500 rpm, on a 140 A3. Only started recently but most noticeable when under load, worst in the back. Get it on a ramp this weekend hopefully and have a look - any other suggestions very welcome

[Fredestairs]

Hello guys


I my self have an Audi B6 130 with manual 6speed... I TOO have this VERY annoying "booming" resonance at approx 1800 rpm both at load and no load...


A couple of years ago my dads VW Passat 1,9 tdi 110 had the same noise/vibration...

At that point i looked at it and "thought" it to be the center muffler, this was replaced with an original one but it didn`t help a bit on the booming noise...

Weeks later i gave i another shot and had the car on a ramp.. Here i had my mate rev it, while standing underneath and feeling/supporting the exhaust... The
second the exhaust is supported/lifted the noise disappers... Soooo i had a look at the "flex" bit infront of the catalytic converter and it seemed to have lost its ridgity
somehow...

Bought at piece of flex from the local exhaust dealer (cheaper than a new cat) SEE LINK: http://www.catalogue.bosal.com/pdf/prelim/pp_exh_buk_en.pdf page 16

Cut off the old one and got this new flex bit welded on and "PLING".. noise was gone

You have to measure LENGTH and GIRTH of the flex so u can order the correct one... IT HAS TO BE VERY SIMILAR IN LENGTH or else the exhaust will be impossible to refit
AND be VERY careful to mark where the flange sits in relation to the catalytic converter... or else the exhaust will be impossible to refit

Hope this will help all u "boomers" out there!!!!