Navara D22 (2006) ZD30 bad turbo or wastegate whine

[ljacko78]

lads n lass,

So driving back from Queen Mary Falls two weekends ago and noticed a noise starting once I hit 300RPM and backing off the accelerator (so no engine noise but this mid range pitched 'electric motor' noise) coming from near the turbo.

Haven't driven the car since til this morning when I went for a quick drive round the block once and the noise at 3000 RPM has now turned more into a mid range screech. Parked it up. I pulled the front of the turbo off this morning and inside looked nice n clean. The impella spun nice n freely like it should. There was a small amount of wobble in the centre bearing (0.2-0.5mm) at a guess, but the wobble didn't happen all the time. The blades look OK to me. The hoses are all fine. I didn't take the heat shield off. No excessive oil round intake. EGR was blocked for over 3 yrs now.

Some pics attached and when youtube starts working again I have a video of the noise I'll put up as well. I don't know what the marks on the intake side of the turbo are (like someone had a go with a dremel), but this is the first time I've taken the front off the turbo.

I had a lot of trouble pin pointing the noise - could it have been the wastegate or the flange on top of the engine. Help is appreciated.

Lj

 

[Forefront Industries]

im pointing at the silicone joiner on the top of the motor to start with!

its bunched up and not sitting correctly

the correct size for for that joiner is 2.25" not 2.5.....and it needs to be cut to length so that the end isnt held up by the little tag as yours is

a quick play around with that top hose may find the leak gone

as for the weird marks on the intake of the compressor housing, i havnt seen a stock nissan turbo without them yet....im not sure if its a tiny bit of compressor blade being flung off the wheel during operation or a completely normal casting mark.

other then that here is a list of other things that can make a squealing noise on zd30 nav

Egr pipe at manifold
Egr at egr valve
Egr at plenum
Plenum to head gasket
Exhaust mani to head gasket
Dump gasket
Turbo to mani gasket
Turbo intake gasket
cracked intake pipe
intake pipe to airbox leak
airbox to precleaner leak
blocked airfilter
leaking map sensor
leaking joiners on cross over pipe
loose allen bolts on turbo
loose 10mm bolt on turbo
loose turbine to chra bolts

 

[ljacko78]

Thanks. Yeah the top join isn't pretty but it doesn't leak (I've watched that one for ages and its been on for a while without issues). The noise isn't from there.

Interesting (and good to know) those markings seem normal.


And I've had a list like urs in my mind as well..... Wish I could get youtube working to play the noise

Lj

 

[Forefront Industries]

so where do you feel the noise is coming from luke?

is it doing it free revving in neutral?

 

[ljacko78]

Not when in neutral free wheeling. Will screech in neutral if revved up 3000rmp

First noticed it only when I took foot off the go peddle once revs were above 3000. So engine noise dropped and 0.5sec later it was whining as I decelerated. Today though it turned into more of a screech during acceleration and it was louder.

 

[ljacko78]

Vid finally came up on YouTube, noise is very audible from 56 sec onwards (its the higher pitched whine/screech)

http://youtu.be/9WAfUPOyEzM

Ta

 

[Forefront Industries]

i hear it right at the end.....but sounded more belt related to me like a bearing in the alternator etc

 

[ljacko78]

Well that would be better than turbo..... Will keep fiddling

 

[Old.Tony]

I'm leaning towards turbo bearings now that I've checked the manual and read this post.

Shaft wobble should be ZERO. End-play (in-out) should be 0.002 to 0.006mm max.

0.2 to 0.5mm of wobble translates to a lot of movement. At high turbo rpm (and remember these things spin at 60,000rpm or higher) the shaft can start to vibrate and produce a buzzing sound. Eventually the shaft off-centres enough for the impeller to start rubbing on the face of the turbo inlet housing. Remember the tolerances are fairly tight - you can't have this nice impeller spinning away like mad and all the air leaking around through large gaps.

 

[Forefront Industries]

get it to do it in nuetral again like the vid....then use a piece of garden hose to your ear...put it on the pulleys at the front of the motor and the turbo centre see if you can pin point it that way

 

[ljacko78]

good thought and will try later....

I dri-lubed the belt, silicone sprayed the iddler, replaced that 2.5" joiner F.I. mentioned with the correct 2.25" tube, and the noise persisted in neutral and in gear.....

 

[Forefront Industries]

Ok cool next is hose test

 

[bods]

I'd also be looking at egr pipe, especially where the blanking plates are. If not there possibly either exhaust manifold to turbo or manifold to head gaskets possibly.

Another thing to check is maybe compress the silicon hoses by hand and roll them on your hands or a solid surface to make sure there's no hairline splits that open under boost.

 

[ljacko78]

Had all hoses off this morning and no holes. EGR plate is ok too

 

[bods]

I'd be looking at gaskets then in that case. You could try looking at alternator bearings if it is related to rpm more than boost though...

Does it get louder if you put your foot down at lower revs or does the noise only increase with revs?

 

[ljacko78]

Hi Bods - the noise only occurs when revs are above 2500 and only get louder with increased revs

If I disconnect the hose on the actuator near the front of the turbo, rev to 3000 to see f there is no noise, is that also a logical step? Won't hurt the turbo at all???

Lj

 

[Old.Tony]

Do you have an intercooler? If so, continue testing like this = no problem.

If you don't have an intercooler and that turbo disintegrates, your motor could be history.

 

[ljacko78]

What i was tetting at was if I can disconnect the turbo by pulling that little hose off, it won't be spinning at all and therefore safer.... so if the noise isn't there once i pull the hose to disconnect the actuator, then rev the engine a bit, if the noise is still there (when the turno isnt spinning) then the problem isnt with the turbo

 

[Forefront Industries]

No no no ..... Disconnecting that hose equals unlimited spinning of the turbo (unlimited boost)..... You are on track but its the OTHER end of the wastagate you want.... Flick the circlip off and take the arm off the wastagate flap and make sure its clear of the flap
This will allow you to do some testing on thw boost related part

I still reckon belt or pully bearings too ..... Did you remove belt and try and see if the noise is there?

 

[ljacko78]

thanks for the tips!

Lj