Exhaust/Engine noise in Superb 2.0TDI 170ps (4x4, DSG)

[iperry]

sydoggkdy, sounds interesting, How're you getting on with it after a couple of days? Couple of other questions:

 

1. What was the age and mileage of your car? Ours was only 3 years, 17k when we got it so seems early for a mount fail. Weirder things have happened though.

2. Was it a DIY job to change the mount? If so, how difficult?

 

psycho6149, noise on our car is not gear dependent. 4th 5th or 6th will make the noise at 2150 RPM when under load (probably lower gears too but harder to maintain RPM and load in those gears). Also, I'm 80% sure the noise is coing from the front on ours.

 

Cheers,

 

iep

[PipH]

Have you checked the rubber hoses & joints in the induction pipes between the turbo/ intercooler/ inlet manifold.

The joints can leak or blow apart under pressure ie when the engine is under load.

The rubber pipes sometimes develop splits which only become obvious, again when under pressure when the engine is loaded.

 

Both leaks are usually accompanied with a slight spray of oil mist that will have got past the turbo seals.

 

The oil mist depoits itself on adjacent surfaces.

So have a good look around these pipes with a torch looking for telltale oil spray marks.

[bigjohn]

On 07/05/2018 at 09:21, iperry said:

Hi,

     I've posted on this before but wanted to raise the issue again now I have had a year of ownership.

 

We own a 63 plate Superb Estate (Elegance spec) . 20000 miles, good condition, running well. It's the 170ps engine with DSG and 4x4 options. All in, a tremendously useful car.

 

Only issue that detracts is that it has always been noisy on the motorway. Up until around 60mph it is quiet with only the expected tyre and wind noise. As you get towards 70mph though  (just over 2000 rpm) the engine/exhaust noise increases significantly and you hear a steady drone from the front of the car. Several people have mentioned this unprompted while in the car so, for a change, this is not just my OCD. 

 

I've been down the usual tyres/tracking path and am confident it is not this for a couple of reasons:

 

1. Had tracking checked and it is spot on.

2. Tyre wear is even without any signs of scrubbing

 

For all the world it sounds like having a small hole in the exhaust but I have not been able to locate anything like that.

 

Reviews I have read suggest the car is generally judged to be pretty quiet at all speeds plus my mate's 140ps 2wD manual car is definitely quieter than ours. Does anyone have any thoughts/experience that might explain what is going on here?

 

Cheers,

 

iep

 

 

 

 

I had a Passat td that was noisy at motorway speeds - turned out to be a damaged downpipe/catalyst, only found after it failed an MOT years later(rust!) and was replaced - suddenly loads quieter at certain speeds although this was never a refined car. Can only presume something was causing back pressure of some sort.

 

I still wonder if it something to do with the Hadlex setup as later types don't just transfer power to the rear when there is wheel slip it's all the time with different percentages depending on driving needs. You mention tyre wear is even - but is that comparing front to rear as well? It's a bad thing for a 4wd's to have different wheel circumference front to rear.  Indeed on some cars if you have a puncture that cannot be repaired so need a new tyre then all 4 should be replaced. Transmission "tension" can cause all sorts of issues (re noise, bearings, shaft joints, oil etc)

 

 

 

 

 

 

 

[iperry]

Ta for comments.

 

Tyre wear is pretty even on all corners. Identical tyres too so pretty sure haldex is not source of issue.

 

Additionally, noise follows turbo. If cruising with low throttle (downhill say) and then apply more throttle the noise only occurs after the turbo lag. It also sounds/feels exhaust related.

 

No sign of any oil spray round the back of the engine but did take a look. One thing I noticed was a slight smell of exhaust fumes round the back of the engine. Can't be sure though that these weren't just being blown back under the car from the exhaust end.

 

I think I need to get it up on some ramps and take a proper look.

 

iep

[Alfashark]

On 7/2/2018 at 19:15, iperry said:

Ta for comments.

 

Tyre wear is pretty even on all corners. Identical tyres too so pretty sure haldex is not source of issue.

 

Additionally, noise follows turbo. If cruising with low throttle (downhill say) and then apply more throttle the noise only occurs after the turbo lag. It also sounds/feels exhaust related.

 

No sign of any oil spray round the back of the engine but did take a look. One thing I noticed was a slight smell of exhaust fumes round the back of the engine. Can't be sure though that these weren't just being blown back under the car from the exhaust end.

 

I think I need to get it up on some ramps and take a proper look.

 

iep

 

Clearly your car has a 170CR engine, but my PD140 powered 2009 Superb suffered from an issue much like you describe - A noise rather like a small exhaust leak, the slight smell of exhaust fumes from the rear of the engine and also a hissing much like a boost leak when any form of load was applied.

 

After much prodding and probing of all the boost hoses and their connections I was ready to concede defeat until a mate with a hoist got me to pop it up and have a good look from below... Took him a few minutes to spot, but a small flange gasket on the EGR pipe had disintegrated.  If memory serves me correctly, it was at the EGR valve end so there was the faint blowing exhaust noise at idle, and when the valve shut under load, the exhaust gasses with nowhere to go were all buggering off through this tiny gap and making the hissing sound.

 

2x gaskets and maybe an hour of labour to get it sorted.

 

Fingers crossed yours will be the same or very similar.