help

[peter w]

When I turn off the motor you hear what sounds like a dry bearing noise You can not hear it while it is running It has just started It only goes for about 6 seconds after you shut down the motor I will take it to nissan when the open Any ideas Peter

 

[Dave]

What engine ?

Dave.

 

[ralphn]

peter
by the sounds of what you describing and assuming its a d40 with the yd engine it will most likley be the one way clutch in your alternator.

If it is d22 with the zd engine i would suggest having a look at your tensioner bearing failing that using a long screw driver and your ear try to pin point the location of the sound or even remove your drive belt and have a feel of all of your idelers and bearings

overall it sounds like a exsternall sound to to the engine well i hope so for you atleast
so get a stephscope from super cheap and see if you can locate it or as i said before a long screw driver and your ear will do the same trick in most cases
good luck

 

[peter w]

Its a 2.5yd motor stx40d the motor stops but the dry bearing sound go on for a good 6sec after every thing has stop moving I am thinking maybe turbo bearing I have just ran out of the first warranty But luckly I got the extended warranty Brought it on the 5th of dec 2007 Thanks for your advice I have not started once I heard the noise Peter w

 

[Dave]

Sure its not the metal contracting as it cools down.

Other then that, no idea.

Good luck.

Dave.

 

[Old.Tony]

I think there could be a couple of things here and an easy way to check them.

Cooling Fan
The cooling fan in the Navara has a clutch that should release when the engine is turned off. The engine may stop and the fan might still spin over for a few seconds. If there's a bearing issue in there, you'll hear it. The fan isn't dirt cheap, but you won't have to sell your left one to replace it.

While the engine is turned off, open the bonnet and just grab the fan and give it a spin. It should resist your efforts slightly but the rotation should be very, very smooth without any grittiness to the motion. If it feels rough, this is probably the problem.

Turbo Bearings
These are more expensive, but you need to take care not to make it any worse. First, clean the outside of the air intake lines around the turbo charger inlet. You do not want to risk even a speck of dirt or sand getting in. Undo the clamp holding the hose onto the turbo charger then thoroughly ensure your hands are clean and have nothing under your fingernails. Remove the hose and give the turbocharger a spin. Try to wobble the shaft.

The turbo should turn over really, really easily and the shaft should not wobble at all. If it feels rough to turn, there's probably a buildup of varnish in the turbo bearings caused by shutting the motor down before the turbo has stopped spinning and cooled enough.

If the shaft wobbles, the varnish has been in there long enough to destroy the bearings. You need to determine if the compressor has ever touched the sides of the housing - it's a dismantle job, unfortunately, but a competent workshop should be able to do that and tell you if it's just a bearing replacement (and varnish removal) that you need, or if you need to replace the whole turbo.

I don't think it's the air conditioning compressor, because they don't use clutches in the compressor belt drives any more - they just vary the compressor usage from 0% to 100%.

You could try giving the alternator shaft a good shake with your hand. It should not wobble or push in or out at all - but I'm not sure there's enough momentum in the alternator for it to run for 6 seconds after a shutdown.

 

[peter w]

Thanks Guys It was the front bearing on the alternator making all the racket Getting fixed now waiting for a new alternator to be fitted So thanks again Peter

 

[scottybobcat]

Glad to see you got it sorted mate.

 

[craig fitzpatrick]

have you had it fixed if not where are you located i have the altenator of my ute you can have cheap it works fine