09 M45 making wierd sound front left of engine [SOLVED - Idler Pulley]

[mactaite]

Hello everyone, my M started making a wierd sound yesterday. Only make it as I accelerate. I made a quick video. The vibration and sound seems like it is coming from the right of the water pump. I'm guessing that is the timing cover but I'm not sure. Any help or suggestions would be great thanks.

[mactaite]

Can someone tell me what is behind this cover. I'm at work now but planned on going through edbwoy videos when I get off to see if it is on one of his videos

[EdBwoy]

Behind that cover you have your intake camshaft and towards the bottom is your variable timing solenoid. The camshaft in turn runs a chain by a tensioner and along a chain guide.

I couldn't make out the sound clearly from the video, does it sound like a rubbing/low pitch whining sound?
The chain is metal and the guide is a plastic layer over a metal arm.

[mactaite]

It is more of a whining sound. I used a long screw driver to feel for the vibration, and it felt like it was coming from that area.

[EdBwoy]

Worst case scenario, your chain is rubbing on the guide. The tensioner could also jam and make the chain slack, but that is usually a slapping or rattle sound.
Have you been keeping up with your oil checks & changes?

Try disconnecting the plug to the solenoid and see if it has any effect on the noise. [#2 in the pic below]
Also, test to eliminate the throttle body as the source of the noise.
... as well as checking the idler pulley/AC compresdor on that side of the engine.

[LIBRILZ]

I had this happen on a G37 I worked on One of the idler pulleys was bad and the alternator was bad. To me that sounds like an idley pulley, I would take off the belts one by one until the sound went away and see whats going on. I highly doubt you have timing chain issues, you never hear that on these engines

[mactaite]

So I checked the solenoid and that didn't change anything. But I did notice a lot of vibration coming from the idler pulley. I didn't pull the belts off because the car was hot from driving but I think your right Librilz.

Do i replace the whole pulley or will changing out the bushing be enough?

[LIBRILZ]

Usually you'll have to buy a new pulley from Nissan or something like that

[EdBwoy]

You can buy a replacement idler pulley from AutoZone. It is a lot more convenient than shopping around for the bearings and pressing them in/out... And much cheaper than going the OEM route.

Part numbers here - https://forums.nicoclub.com/topic589191.html#p6763798

... But first you have to truly isolate and find the root of your issues before we get to replacing parts or taking things apart.

[mactaite]

Thanks for link Edwboy. I have taking the belt off and the idler pulley is making a sound and hard to turn by hand. I just picked up one from the auto parts store and will replace it tomorrow. My question is, do I have to take the whole pulley off with the housing? I see in your video you remove the 3 bolts holding the metal housing then remove the center bolt when it is off the car. Can I get the pulley off the housing while it is still on the car by just removing the center bolt and prying it off?

[mactaite]

Decided to go ahead and replace it. That was the culprit and the sound has stopped. I planned on doing the tensioner pulley next as preventative maintenance. I am approaching 200k miles.

Thanks for the help!

[EdBwoy]

Right on! Thanks for the update.

And btw, yes you can replace the pulley with the bracket still mounted. It could get a little tricky to get tools and secure the back of the big bolt though.