Crank pulley chirp

I have a 2009 Maserati granturismo S, with 59000km. My crank pulley makes chirp noises once the engine warms up, only during idling. See these videos:

https://www.youtube.com/watch?v=DyY7f-juS-I

https://www.youtube.com/watch?v=fGRae2fWaug

I sprayed lithium grease on the inside of the pulley. See red arrow in pic.

The chirp then disappeared. See videos:

https://m.youtube.com/watch?v=5NIQxuPf5pk

https://m.youtube.com/watch?v=fnzPNHU6GWc

After a week or so, the chirp is back. Does anyone have any idea what the problem is and how to solve it? Thanks in advance.

You have a budgie in there!!

So sorry, couldn't resist!!

D Walker said:

You have a budgie in there!!

So sorry, couldn't resist!!

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LOL how do I kill that budgie in there?

Try spraying water on the pulley. If the squeak / chirp stops then you probably need a new belt or a little more tension on it to stop it chirping.

Sounds like you could do with a new belt/tensioner. I would be tempted to just try a new belt first.

spkennyuk said:

Try spraying water on the pulley. If the squeak / chirp stops then you probably need a new belt or a little more tension on it to stop it chirping.

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MGT said:

Sounds like you could do with a new belt/tensioner. I would be tempted to just try a new belt first.

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I already replaced all belts. Here's a more thorough explanation of what I've done so far.

I used the water spray method (I couldn't reach the crank pulley but sprayed water on the top pulleys and belt). Noise did not change. I replaced all auxilary belts anyways. I used a gator back (4060615) and Maserati stretch belt for the water pump belt (214271), noise was still there.

Second, I tried reconditioning the idler pulley (227894). Still nothing changed. I replaced the pulley with a new one since there was some wear and tear on the bearing. Still no change.

I greased the inner of the crankshaft pulley. Noise completely gone for a very short period of time, then came back.

Only really the tentioner left. I cant figure out why the noise is going if you spray grease behind the pulley unless not all the pulley studs / bolts are fully tight allowing the pulley to move slightly while rotating.

You could try putting some tipex or white paint on part of the edge of the pulley in a few places. When the engine is running the mark tipex marks should appear as a straight line. Any play and the line should wobble back and forth.

I haven't watched your videos, but there was a factory bulletin for the GS, which has the same basic motor, to adjust the angle of the alternator to overcome a squeak.

BL330 said:

I haven't watched your videos, but there was a factory bulletin for the GS, which has the same basic motor, to adjust the angle of the alternator to overcome a squeak.

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You are referring to bulletin 200722 for models M138 and M139. The cause of that noise is the auxiliary belt due to angle caused by alternator being to forward.

Not sure alignment is the issue here. I looked at that already, the alternator angle is off by 1 or 2 degrees on my car. I have a gator back serpentine belt which allows for that kind of misalignment. Also, a misaligned belt will provide a constant squeal, whether the engine is cold or warm, which isn't my case since it only squeals once the engine is warm, on idle, in a pulsating manner.

Also, if it was an alignment issue, the noise would have temporarily disappeared or diminished when I sprayed the belt with water. In my case that did not happen at all.

The crank pulley didnt get any water on it if im reading your post correctly.

Probably not going to help you much but if it only happens when the engine has warmed up and not under load then it suggests the play is only occuring when a metal part has expanded with heat giving more play or when a greased / lubricates part has warmed up and the grease / lubricant has thinned out.

Under load the chirp is probably still there but the noise is being masked by the higher belt speed.

I did manage to find this if it helps which also suggests the 1 or 2 degree that your alternator is off would be enough to produce the chirp.

On the link scroll down the page to the diagnosing misalignment and belt noise section.

http://www.daycoproducts.com/diagnosing-misalignment-and-belt-noise

I ordered the pulley tension. In the meantime, I'm continuing to study this entire system to better understand it. There isn't much behind the harmonic balancer that can cause that chirp (see picture). There's just a gasket. The grease I sprayed may have been spun off and landed on other parts, such as the pulley tensioner (which is not very far in distance). After I sprayed the grease, a line of grease appeared in the environment. It can't be the crankshaft pulley, focusing on the pulley tensioner for the moment. I will report back eventually when I get it and install it (it will be a long while before I can do that).