Weird noise accelerating @ 2500rpm - advice please!

[davcom1]

Hi all,

I've just renewed my membership and so this seems like a good time to pick yer brains!

I'm due an oil change and have the oil and filters ready but...

I'm getting a "tinny" sounding vibration noise when pulling at around 2500 - 3000rpm. It's more noticeable when in 2nd and 3rd (autobox) but this could be down to road speed(?)

There's no feedback of the vibration through the car, just the noise.

It sounds like part of the exhaust vibrating - loose baffle or similar but I can't replicate when parked and revving which makes me worry that it might be in the transmission... *seems* to be towards the nearside of the car.

Any ideas of a methodical approach to finding the cause would be appreciated!

BTW, the noise is more obvious when driving up an incline or on the flat than downhill - why can't I just have obvious faults like a blown lamp or flat tyre??!!

:violin:

Thanks in advance...

[Ryan]

I had a similar problem a year or so ago (weird rattling noise) and it turned out to be an engine mount that required changing.

[Turbo_Steve]

when you say "tinny"...is it like someone dropping bolts into a metal tin? If so....it could be det!

[davcom1]

Cheers Ryan, although this is more of a buzzing sound than a rattle - will add that to my checks though!

[davcom1]

Steve - the sound has a high frequency... the car does seem to be a bit sluggish lately (compared to normal) but this might be paranoia!

[Atik]

Split hose?

[confusis]

my primera had a similar issue - passengers engine mount was toast.
sounded rattly on acceleration, uber nasty grinding on decel

[Turbo_Steve]

this might be paranoia!

I'd suggest you invest £20 in a set of listening cans. Bit of copper pipe, some garden hose, pair of builders ear muffs, some jubilee clips and you're away!

[richTvr4]

I had a Tinny rattle a while back, coming from the engine bay, it only happened when lifting off the gas slightly- It ended up being a slightly worn Wastegate rod which was worn and rattling.

[John TheAntique]

You don't need to spend £20 http://cgi.ebay.co.uk/MECHANICS-NOISE-LOCATING-STETHOSCOPE-CAR-REPAIR-ETC_W0QQitemZ110502702488QQcmdZViewItemQQptZUK_Han d_Tools_Equipment?hash=item19ba796d98

[Davezj]

i have one of these, they work really well,

but only advisable to use them when the car is stationary, LOL.

[Davezj]

I have always had a whine/whistle from the at certain rpm's when cruising on the motorway at 60 in 5th with very little throttle.
i think it is coming from the gearbox, but it has been there for 3 and bit years and not got any worse so i am not bothered anymore. it is just a little reminder to go a bit quicker.

[davcom1]

I'd suggest you invest £20 in a set of listening cans. Bit of copper pipe, some garden hose, pair of builders ear muffs, some jubilee clips and you're away!

Worth the five minutes to put together although the noise is not there when stationary and no noise during slowing/foot off gas.

Didn't hear it today at all - fixed with a simple volume control on the radio! /lol

[Davezj]

just remembered, friend of mine had a noise when doing 50mph and only when turning slightly from centre to right. we are only talking 10 to 20 past on the steering wheel. you could only describe it as a little hum from the passenger footwell.

but never found out what it was. sorry

thought it could be some body work vibrating in the wind maybe the inner wing panels, arch liner of gear box cover.

you could try putting some extra cable ties to fix these panels in place. the least it should do is change the noise. then you know it is something to do with those. if it does not change then it is something else to tick off the list.

[Turbo_Steve]

although the noise is not there when stationary and no noise during slowing/foot off gas.

You put the hose on the copper pipe with jubilee clip.
Hammer the end of the copper pipe flat.
Drill a hole in the flat bit.
Bolt the copper pipe to the engine block.

Run the hose through the window into the car.
Connect drill a hole in one of the ear muffs.

Stick the hose in the hole. Hot glue it so it stays there, if you like.

Get a passenger to wear them whilst you go for a drive. If it's detonation, you WILL hear it, clear as a bell. You'll also hear a lot of other enginey noises which are quite interesting.

[Davezj]

that sounds an interesting gadget.

i might make one of those for my self.

[Turbo_Steve]

Ghetto Det cans, dude: essential for any tuner!

Can also be bolted to such components as the "whats this thing?", the "is this the fuel rail?" and the "I wonder if this pump works properly on boost" as well as "Is that clunk the aircon clutch" and "OMG Can I hear a noise in the bottom end!" :D

[Davezj]

yes, sound very usful.

you could probably bring the hose out from under the back of the bonnet and through the window.

i have a couple of small microphones that are bolt on jobs so i could use these and amp up the signal through the car stereo on the AUX signal input. then i could do it on my own and listen for the noises in stereo

[Turbo_Steve]

Many people do!

It's not quite as ghetto, though, and unless you get the gain structure just-so, it can smear out some of the more interesting details. That being said, the ability to increase the volume is useful in the extreme, and you don't look like an Alien sitting in the passenger seat staring into their lap(top) with an AFR meter in front of them and big earphones on.