Strange noise

[mikel]

Our 2012 MY 2.7 D4 has developed a strange noise coming from the engine bay.
Basically the noise appears from 1500 to 2300 odd rpms under normal driving in drive. The noise is similar to a fan belt / power steering pump type whine and can be heard from both inside and outside the cabin. It can be heard 20 m away when taking off up a slight hill. We have had the noise checked out by the dealer and when the mechanic heard the noise from inside the vehicle after 50m of driving, he mentioned "that's a new one on me".
The noise started out as "occasional" but lately developed into almost constant while being driven within the rev range above. The noise goes away above 2300 rpms but will reappear when accelerating after the revs are lowered again. No noise is heard while the vehicle is revved while stationary.
I have dropped it back to the dealer for the last 3 days and they apparently have been unable to hear it again having been driven for upto 30 mins each day. The noise was definitely there when I dropped it off after driving 30 mins to the dealership on Tuesday.
I'm back in Sydney tomorrow arvo and will pick it up again.
I'm concerned that it may be transmission related or be the start of something serious.
Any ideas what the noise may be or way to isolate it? The dealer was going to use their "chassis ears" to try and find the problem but as the noise was no longer there they have not tried these.

[mikel]

Picked up the D4 from the dealer this arvo and yep the noise is still there.
I will run it for a day or two then take it back and see what they say.
Mike L

[justinc]

Hi mate maybe fly me up one weekend and I'll do some diagnostics for you while we tour around some wine bars and latte shops?. Can i eat croissants in the car ???

☺ jc

[justinc]

And by the way my guess is it is engine/ turbocharger not trans related most likely a boost leak somewhere. The giveaway is no noise until load is applied and that rev range is right on the money...

Jc

[LandyAndy]

The nannocom man posted recently about a cracked inlet manifold,they are plastic apparently.
Worth looking up,even if you have to try a UK website,havent heard of it on here.
Andrew

[justinc]

The nannocom man posted recently about a cracked inlet manifold,they are plastic apparently.
Worth looking up,even if you have to try a UK website,havent heard of it on here.
Andrew

Sounds like a good place to start andy!☺☺☺ i read that post forgot all about it!!

Jc

[BobD]

Mine also had the cracked plastic manifold as per my posts and also in the BBS post. This causes limp home mode under hard acceleration which can be cleared initially but once it gets worse there is a loud hissing sound when the turbo is on boost and it will keep faulting during normal driving.

[mikel]

Thank guys for the prompt replies and advice.
I will broach this with the Dealer this week.
NO jc you can't eat croissants in the car :-(
Cheers
Mike L

[justinc]

Thank guys for the prompt replies and advice.
I will broach this with the Dealer this week.
NO jc you can't eat croissants in the car :-(
Cheers
Mike L

😣😣😣 oh well worth a try. Hope they get to the bottom of it ☺

Jc ☺

[SBD4]

I thought the cracked manifold had only been seen in 3.0L engines. Is that right?

[LRD414]

I thought the cracked manifold had only been seen in 3.0L engines. Is that right?
The one written up by BBS Guy is a 3L RRS (link below) and BobD's was on a 3L D4.
But perhaps still worth having a look for a similar issue.
Mike, the photos in this thread are excellent so you may be able to identify it visually if yours is similar:
http://www.aulro.com/afvb/d3-d4-rrs/226600-3-litre-inlet-manifold-crack-problems.html

Scott
.

[Tinman]

I had a noise just like that lasted for over 12 months could not put my finger on it, until my high pressure fuel pump let go when on holidays and wrote my car off. My be the bearing in the hp fuel pump that is making the noise. Worth a look

[mikel]

Had the dealer do a "smoke test" today on the inlet system and they could not find any leak/s.

I was able to reproduce the noise almost at will (1600 to 2300 rpm) while driving in D2 and D3 and they described the noise as a "cherp". The noise definitely does not appear while stationary, simply being revved.

Tinman what side of the engine is the HP fuel pump located on? The "cherp" appears to be coming from the lefthand side of the engine compartment.

I will keep that in mind and ask them to include it in their list of things to check.

Cheers

Mike

[justinc]

The chirp is it 1 chirp or a long one under load?. I have seen an exhaust leak at the turbocharger mounting flange that was responsible for a similar sound. The turbocharger is passenger side rear whereas the HPFP is central rear. Is it worse when hot or cold?

Jc

[mikel]

Hi jc

The "chirp" tends to be constant while in the rev range and I assume on light boast. As mentioned I was able to maintain the "chirp" while changing manually from D2 to D3 while within the 1600 / 2300 rpm range. It may change volume but is present for more than a once off "chirp". Possibly worst when hot.

Cheers

Mike

[Tinman]

My chirp was not there when the engine was cold but appeared when warming up of the motor. When in top gear no noise at all but the same as you have described. Some days you wouldnt even hear it. It was very puzzling for me also.
Cheers

[LandyAndy]

Mike.
Try using sport and manual shifting and a bit of punishment too.At least you can then work out when its happening and the way it happens,it will help you replicate the issue for the shop.If you can consistantly get it to work,then get them to data log whilst you are steering.
I had issues with my last CAT grader consistantly de-rating with an oil pressure warning.They replaced electronic bit after electronic bit trying to sort it out.
In the end it impressed them how I could make it de-rate.They data logged it over 20 passes of the same bit of road.They said every de-rate was at 0psi oil pressure.
It had the engine out,it turns out there was a faulty oil pump batch wich was fixed in factory before mine was built.Somehow mine got a faulty oil pump.They rebuilt the bottom end whilst the motor was out.
The more info you can provide the workshop the more they can look at.
GOODLUCK
Andrew

[mikel]

We are hopefully getting somewhere as the dealer has identified the HP fuel pump as the source of the noise and has ordered a replacement.

I will keep you updated.

[scarry]

How many k's,interested as mine is also MY 12,no noise yet…..

What kind of $$$ to replace pump?

[mikel]

96000k's and no idea about the cost, as it will be replaced under extended warranty(thats the plan).

[mikel]

Finally got the D4 back from the dealer today.
They replaced the HP fuel pump under extended warranty which appears to have fixed the "chirp" at an estimated $3000 warranty cost.
They also found a leaking EGR gasket that was leaking exhaust straight into the HP fuel pump area making a mess everywhere.
Unfortunately this required a "body off" to locate and replace the gasket, delaying the job further as all the front and rear aftermarket bars etc had to be removed.
I will give it a good run over the next day or two and hopefully that's the last of the "chirp".
It pays to trust your gut and get noises checked out to your satisfaction.