Discovery 4 TDV6 3.0 Whistle / Whine / Squeal

[eddielines]

Hi

I've had a whistle / whine develop intermittently. When I described it on phone Indy thought it sounded like exhaust leak at manifold or turbo flange, of course when I've taken I to indy it's not reoccuring and there is no spot around this area.

It sounds like it's coming from drivers side and rear. If anyone has any ideas that would be helpful. Shared album - Clement Lyons - Google Photos (https://photos.app.goo.gl/tfGwbvVS2HEnrsoa6)

Inlet manifolds were replaced about 50k ago and I've smoke tested inlet and no leaks or error codes.

A couple of other points is one or twice while the whistle / squeal was there there was a slight vibration that I could just about feel / hear up through the snorkel.

Also not sure if real or in my mind, but while I don't use it much I think it isn't holding speed as well in cruise control.

Any thoughts or shared experiences are welcome.

[Eric SDV6SE]

Sounds to me like significant cam chain rattle in the foreground. The whistle in the background is the turbo spooling up. The rattle would be 1st concern, I think the timing chain guides are worn out, running against the metal backing plate. These engines run a timing belt on the front of the engine from the crank to the outer (exhaust) cam on each bank, then a chain from there to the inner (inlet) cam on each bank. The tensioner sits vertically up between the camshafts, one on each bank, keeping tension on the short chains. When the guide wears out, the chain runs along the backing of the guide, and tension is not what it should be. Risk is if you snap the chains or they jump a tooth or two, valves will hit pistons as they're an interference engine. Relatively easy to replace the tensioners, more costly if they break. The hardest part is getting the manifolds off, as the injectors have to come out, so you need new crush washers for that, and the crossover pipe and throttle Y piece are a fun challenge to get out. 180k km seems a little low for timing chains, but not unheard of

[eddielines]

Thanks, it's with Indy at the minute. I will ask him if there is timing chain rattle. Sometimes it's difficult to get what you hear on recording.

Always had the spooling up, but in this there is definitely an addition whistle / squeal beyond what is normal from turbo. Note also the whistle appears to be at rear drivers side of engine, where exhaust manifold / secondary turbo is. But the whistle / squeal is at lower rpms than when the secondary turbo kicks in at 2800 or is 3000 rpms.

I did share this video with the Indy and while yet to talk to the mechanic the guy on Desk says based on the video he believes it is exhaust leak. But will also ask about timing chain. but

For myself really the engine doesn't sound any different to when I bought car 5 years ago.

I can't hear for example the extra metallic noise as in DISCO3.CO.UK - View topic - Discovery 4 ticking noise at idle when hot. (https://www.disco3.co.uk/forum/topic163370-15.html) which was fixed with replacing lifters

[Eric SDV6SE]

It definitely doesn't sound like that engine should, that's for sure.

[coopers1969]

Wow that sounds horrible does it happen from cold and get better or after a long hill decent

[Jason.k]

I just purchased my 2014 TDV6 yesterday...only 108,000km, and this morning when it was stone cold i noticed a whine too. It got better as it warmed up, although not completely gone now that i can hear it it's stuck in my brain. Sound frequency sounds linear with revs...similar to what you'd get from an old school car radio with induced electrical noise.

Is this similar to yours?
Edit: sorry didnt notice the link to the videos...it sounds nothing like yours

[BradC]

I just purchased my 2014 TDV6 yesterday...only 108,000km, and this morning when it was stone cold i noticed a whine too. It got better as it warmed up, although not completely gone now that i can hear it it's stuck in my brain. Sound frequency sounds linear with revs...similar to what you'd get from an old school car radio with induced electrical noise.

That sounds like the serpentine belt tensioner.

[Jason.k]

That sounds like the serpentine belt tensioner.

Interesting....I guess that would also probably align with the A/C whine I've got - when A/C is switched on the same??? whine is evident (but far louder)

[BradC]

Well, it's an extra significant load on the belt so I wouldn't rule it out.

[eddielines]

Just looping back to close this out and answer few questions above.

No it wasn't just at start up and go away when heated up, it was persistently there for a few weeks getting louder and then went away. I shared the recording with Indy and he was pretty sure it was leak at exhaust side. it probably came and went a bit just due to expansion and contraction on heating and cooling of exhaust and whats around it.

I'd already established it wasn't serpentine belt as when it was there persistently I ran it for a minute with the belt off and it was still there.

We took body off and yes there was a coupe of bolts / nuts loose / broken on exhaust manifold, but the gasket between exhaust manifold and turn were also blown. He showed me gaskets and pictures of manifold.

He said it wasn't urgent, but glad I did it, frustratingly he found and again showed me pictures for
1. I had turbos and rear belt done about 4 years ago with reputable indy, but as body off had him do rear belt again hoping a long time until body off again, the tensioner bolt was stripped, probably because they unscrewed bolt with belt on when practise is to cut belt and also a couple of bolts missing from rocket cover
2. top right both was missing from TC into Trans, Trans was rebuilt 2 years ago

He has also had a good look / listen around engine and not hearing cam chain clatter, but I will monitor for this.

Also had radiator replaced at 14 years and 190K I was losing a little bit of coolant and there was some moisture around top of radiator.

So all seems good with the engine running well, not burning any oil, on to a few other bits and pieces of my mid life tidy up.

[PerthDisco]

A small amount of coolant dripping on the accessory belt makes a lot of very scary noises.

[eddielines]

This was a couple of broken bolts on exhaust manifold, was sorted last year and not returned.

[baggy17]

I just purchased my 2014 TDV6 yesterday...only 108,000km, and this morning when it was stone cold i noticed a whine too. It got better as it warmed up, although not completely gone now that i can hear it it's stuck in my brain. Sound frequency sounds linear with revs...similar to what you'd get from an old school car radio with induced electrical noise.
Is this similar to yours?
Edit: sorry didnt notice the link to the videos...it sounds nothing like yours

Hi Jason (and everyone) - I have the same noise problem, i.e. "old car radio with induced electrical noise" type of whistle. Starts around 1600rpm then linear increase with revs until you cant hear it over other noises. Had the main turbo replaced recently and from then it started making the noise. Also had the timing belts, etc... done at teh same time.

Did you get a resolution to your problem?

Vic.