Whining noise on deceleration

[Ryno91]

Hey guys, on the way home yesterday I heard a noticeable whine when decelerating around the 2000-1500 rpm range, also sometimes when accelerating. A blow off sound also happened during a gear change but this was only happened twice during the drive.

My guess is the hoses to the turbo have worn or it could be a fault in the actual turbine itself. The nav is now waiting at the workshop and I'll update as soon as I hear from them.

Anyone else had a problem like this?

 

[steve1961]

Sounds like a split turbo hose

 

[Ryno91]

Sounds like a split turbo hose

Hopefully its just that, and it only seems to make the noise when the engine has warmed up..

 

[Ryno91]

Well the mechanic said there was nothing worth spending money on, couldn't find a fault andhad 3 of his guys drive my nav.. sstrange but I'll take their word for it!

 

[steve1961]

Sounds a bit odd if it was a noise that has just developed , but as it's your car your sensitive to its sounds , that a mechanic wouldn't pick

 

[Old.Tony]

If it's happening during deceleration your turbo won't be producing boost so it's not going to be a boost leak, but it could still be something in the hoses and the vacuum is causing the sound. I hope it's not the early signs of timing chain issues (like the tensioner is stuck). You'd need to listen to the front casing of the motor with a stethoscope to hear that properly, and know what to listen for - the chain will be riding loosely on the plastic guide and from time to time it will slap it.

I hope it was just a wasp caught in your air intake and every time you decelerated it had the opportunity to lift off from the paper filter and buzz around in the airbox a little.

 

[D22 Dude]

Does it sound like this at all?

http://youtu.be/TAw8YyhPghM

 

[Ryno91]

Tony - it only happens during deceleration, it happened again yesterday, It's hard to describe the noise in words.

Basically you can hear your normal engine gearing noise when decelerating, and then a "wheezing" noise comes on which is considerably louder than your gear noise moments later, if you can imagine someone with asthma struggling to inhale (that's my best description lol).

 

[Old.Tony]

So it sounds like your palm hitting a table multiple times followed by the thud of your body hitting the floor as you asphyxiate then a bit of thrashing followed by silence ... damn, that's no help figuring a cause.

Seriously, I wonder if it's something in the drive train - more specifically, around the clutch/gearbox input. Are you still on the dual mass flywheel? How does the clutch perform under a bit of strain?

I can't see timing chains doing that only under deceleration - the strain on the chain shouldn't vary much between piston-driven crankshaft rotation and gearbox-driven crankshaft rotation. Unless the sound IS there and you just can't hear it because of the combustion noise?

 

[Ryno91]

So it sounds like your palm hitting a table multiple times followed by the thud of your body hitting the floor as you asphyxiate then a bit of thrashing followed by silence ... damn, that's no help figuring a cause.

Seriously, I wonder if it's something in the drive train - more specifically, around the clutch/gearbox input. Are you still on the dual mass flywheel? How does the clutch perform under a bit of strain?

I can't see timing chains doing that only under deceleration - the strain on the chain shouldn't vary much between piston-driven crankshaft rotation and gearbox-driven crankshaft rotation. Unless the sound IS there and you just can't hear it because of the combustion noise?

Hahah I would be worried if it did sound like that!

I think you are right because I have heard it during slight acceleration, other times it was probably muffled by the combustion.

Yes still has the dual mass flywheel, when towing a 6x4 tool trailer it was fine, no odd noises.. if a little more sluggish of the start but that was before I blocked EGR.

I'm really at a loss.. perhaps the next step is to take it to a trusted mechanic and see if he can locate the source of the noise. I'm also considering upgrading to the double row? timing chain to save myself the worry later

 

[Old.Tony]

If you can hear it in both acceleration and deceleration then there's a chance it's a loose timing chain (or a stuck tensioner, which is what destroyed a number of the chains).

You should be able to hear the chain rattling at idle. Take it to a trusted mechanic and have him listen to it with a stethoscope.