Possible turbo problem 2009 D40 4x4

[kwilko]

I recently changed a few bearings and belts on the front of my engine. alternator bearings etc this got rid of a squeal.
however it now makes a whirring sound quite audible. i had assumed as it ran in since with engine RPM tat is was some belt bearing or pulley...or the air con unit...

My local Nissan dealer now says it's the turbo but not a problem.

Has anyone got some ideas on this? - apart from anything I'm becoming fixated by this "whir"

 

[happy john]

You don't mention how many kms or service history how did your dealer diagnose that your turbo was stuffed?,unless they can read a code they would not know their arse from their elbow.I would use a little crc on the belts see if that removes the issue if you have replaced the a/c and alternator bearings all that is left is the power steering pump whilst you are at home remove each belt 1 by 1 give it a rev and you May find the faulty part failing that perhaps the grease monkey is correct.

 

[kwilko]

The dealer says "it's OK"
He diagnosed with a stethoscope

The mileage is 130 km
serviced by Nissan from new.
Replaced alternator bearings but not A/C - they were "checked" by the dealership.
Will check steering pump too

 

[happy john]

The dealer says "it's OK"
He diagnosed with a stethoscope

The mileage is 130 km
serviced by Nissan from new.
Replaced alternator bearings but not A/C - they were "checked" by the dealership.
Will check steering pump too

Unusual the need to replace bearings at such low mileage i had a petrol triton for a short time afer bogging in very deep water and the high lift saved the day the alternator and power steering bearings failed on my way home.

 

[kwilko]

Mine got a serious dunking in mud last September which would account for bearing wear....but still doesn't answer the turbo thing.

 

[Rumpig]

Whirring can be low power steering fluid. To bleed the air out you normally leave the cap off and with the engine idling turn the steering from full lock one way to full lock the other way.

 

[kwilko]

Whirring can be low power steering fluid. To bleed the air out you normally leave the cap off and with the engine idling turn the steering from full lock one way to full lock the other way.

Would the whirring be in since with the RPM? - I sounds pretty simple to try anyhow......

 

[Old.Tony]

Sure could be the steering pump, it's driven by the belts at the front of the motor.

If the turbocharger had a problem you probably wouldn't hear it around idle up to 1100rpm or so but then once the exhaust has enough pressure it should build rapidly. The turbocharger spins at a vastly different rate to the engine (expect at 3500rpm of the motor, the turbocharger should be > 100,000rpm) - any issue with the turbocharger will sound like it's increasing at a different (accelerated) rate compared to the rising engine rpm.

If the turbocharger has such a problem that it's unable to reach normal speed, you'll notice it both as a lack of power/response and in a large amount of black smoke.

Fluttering sounds that are directly related to engine speed will most probably be something attached to the front of the motor. Given the history (stuck in mud) I'd have a look at the fan blades, inspect them for both wear and cracks especially around the root of each blade. I'd also look at the inside of the fan shroud in case that shifted.

 

[kwilko]

I see your point about the difference in RPM between engine and turbo...........I don't notice any black smoke or loss of power - the vehicle seems to be functioning normally. I think my next step will be to take it tot another guy about 20 km away and let him form an opinion. I'm not overly impressed with the diagnostic abilities of my local Nissan dealer or the other nearby chap.

 

[doc]

I'm more inclined to think it's a bearing issue.

Did they replace the OAP bearing? (Overrunning alternator pulley) Or did they replace the alternator shaft bearings? The OAP can make a funny grumbling noise if its on its way out.

There are the idler/tensioner bearings which can make noises - easy to check and replace the entire pulley.

Tubo's don't tend to make a lot of noise until they are terminal. The D40 has a bush bearing - won't just start making noise. If the turbo is making noise, then IMO something is touching internally, and that will only end up with bad news shortly down the track.

Without more info, what you've passed on so far about what the dealer has said just doesn't add up.

Edit: meant to say too - how diligently does the noise follow engine revs? Is it pretty much spot on? Reason I ask is that turbo will lag, compared to both rev increase and decrease.

 

[kwilko]

I'm of the opinion too that it may well be a bearing - of course I'm biased - but it seems pretty diligent in following the RPM.
I'm getting a second opinion tomorrow. I have about 3 barges that I trust and tend to rotate the vehicle between them. This overcomes the tendency for irrational conclusions.
Bea in mind that my local Nissan dealer couldn't even identify a front prop UJ until I told them to check. (after advice on this forum).

In an earlier repair when I had a really squeaky bearing the chap replaced a belt and two (shaft) bearings in the alternator - they may have been spurious parts..