another whine sorry

[Skusto]

hey guys just checking i have searched and it is different to the other turbo whines that have been about lately, i have a 04 d22 str that i acquired recently know it has a whine through out the whole rev range i have tried what tony said but doesnt seam to matter, just wondering could it be the turbo even when u just start to hear it over the engine just under 1k in revs?

just checking cause know im a bit parnoid with it know and dont want the engine to go bang. or is it normal?

also not the gear box as it does it in neutral.

after some researching on google and what not if it was the turbo would the noise go away if u took your foot off the peddale as it would release the boost pressure is that correct? cause if thats the case it still does it if u take your foot off so hopefully i cant tottally rule out the turbo?

 

[scottybobcat]

Have you checked the waste gate and checked for air leaks around the turbo and manifold

 

[Dave]

Get a audio recording.

Hard to say with out hearing it.

Just go over the motor and check things.

Dave.

 

[Old.Tony]

Can you hear it at idle? It would be good to get someone to help raise the rpm gradually to about 2,000rpm while you've got your head under the bonnet. At 2,000rpm your turbo is at full boost, so if something is going to go wrong, it'll happen in that range.

What does the whine sound like? If it sounds like when you fill a balloon with air and slowly release it to make high-pitched fart noises, it's a boost leak. If it sounds like fingernails on a chalkboard, it could be a turbo bearing and in a 2004 model you don't know what the previous owner has done in terms of caring for the vehicle.

You might want to pop the clamp off the compressor (inlet) side of the turbo and try wiggling the turbo with your finger (very, very clean hands required - don't let anything fall inside, not even particles like sand grains). Can you wobble the shaft from side to side at all? ANY movement here means turbo bearings. It should spin freely in either direction, but it should not wobble in the slightest.

If your turbo shaft is wobbling, the bearings are shot and catastrophic failure is shortly ahead, where the side of the compressor will contact the turbo housing and the compressor wheel will explosively come apart, sending small particles down into the engine and destroying it (D22s generally don't have intercoolers which help by catching these bits, apart from the mild performance benefit).

Why would the turbo bearings fail? It's usually heat and varnish build-up, caused by a turbo that's still hot and spinning with the engine shut down. The turbo needs oil flow to cool and lubricate the bearings, but if it's still hot and spooled when you shut down the engine, the oil flow is gone, so the oil that IS there just burns up (creating varnish) and eventual failure.

It might not be the turbo, but I'd focus on that for a moment so you can be sure it's okay. If that's all good, you need to look at other possible causes like the alternator, water pump, air conditioning compressor.

A FIRST stop after checking the turbo is to get a can of silicone lube spray (you can never do without that stuff, it's brilliant - Bunnings sell it) and put a squirt on the idler pulley bearing and start the engine again. Has the noise gone? It's just a bearing, pop it out and take it to a bearing place to have it matched. Nissan buy the bearings for $5.20 each and on-sell them to you at a discount of $247.93 (not including GST).