Noise in my D 40s engine.

[Jeff]

My 2007 - D 40 (118,000Ks)developed a noise similar to that of a loose fan belt which only appeared after travelling 5-6ks and seemed to be connected in some way to the throttle position.
It would come and go as I applied only light pressure to the throttle.
It would scream at me under acceleration from lights etc then shut off once on the go.
Silly me took it to Nissan who told me it was the alternator $1270.00 plus fitting so I took it to my man who agreed re the alternator and replaced it for $850 - what a bargain - until I drove it home and the noise came back.
Took it back to my man (who was very appologetic) and spent several hours working on it and when I picked it up he said all they did was tighten all nuts,bolts and hose clamps and the noise stopped - and so far (3 weeks) it has.

Any Ideas???

Also I tried to get onto the forum re the above but my puter said you had a bad bad virus and would not connect me until I tried again today.
Was it my puter or was there something going on??

Thanks.
Jeff.

 

[Old.Tony]

It was a stuff up by Google. We didn't have a virus here. Some google results were sending people off to a virus - it was Google being dumb. We don't host executable files here!

Anyway, try spraying the idler pulley near the alternator with silicone lube. You'll need to have the engine off, you'll need to use the little stick extension for the nozzle, and spray in behind the round cap to get to the bearing.

Those idler pulleys have been a problem before.

 

[Simsy]

Mine made some similar strange noises turned out to be a leak in the air box. it would scream during exceleration and would go quiet at cruise speed.

 

[4 naving]

Yea I was thinking boost hoses might be leaking.

 

[Jeff]

Thanks all.
Old Tony - thats the first thing I tried and the mechanic did the same but no result.

Simsy - sounds just like it - I always thought it had something to do with an air leak, when the engine was under pressure.
The overall performance was not affected it just made a horrible noise.
I tow a 2.5 tonne van and it did not reduce engine power when towing.
I assume that when they spent a few hours tightening everything they may have accidently fixed the problem.
They said they didnt know how they fixed it but maybe they know but arent telling me.
You tend to think of all the expensive things it could be rather than something relative simple.
At least I know I have a nice new alternator thanks to the "Experts".
Glad I didnt let Nissan do the job as $850 is much better than $1500 that they were happy to charge me.
Ill put it down to experience and try to forget it.

Thanks again.

Jeff.

 

[Simsy]

its a common problem with them when I rang Nissan and explained the noise to them they said air box leak instantly they then said drop by when you can and we will fix it for free. they just put some tape underneath it around 1 of the bolts and said it should last a fair while, haven't heard a peep out of it since.