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06 3.5L noise??

Posted By: 1E2C

06 3.5L noise?? - 06/23/11 02:49 AM

Just picked up a noise in the 300. It's almost like a knock but with a rattle to it. It's not a clearly defined one shot noise, more drawn out. I've only heard it at an idle, got home tonight and heard it when I pulled in the garage. Seems to have a frequency of just over a second, but didn't actually time it. Broke out the stethoscope and couldn't hear anything unusual anywhere I could reach with the probe, but the stethoscope quit working before I played too long. Seems to be most audible when I get my ear down near the right front gap under the intake but I'm not positive it's not reflecting from there. Any ideas on where to start?

Oh, does anyone have a picture of the head with the valve covers off?

Thanks,
Mike
Posted By: 71yelladustr

Re: 06 3.5L noise?? - 06/23/11 03:55 AM

Those late model 3.5 are notorious for the dowel pins that hold the exhaust rocker shafts in posistion to break and allow the rocker shafts to turn and not allow oil to ger to the lash adjusters in the rocker arms. Pull the valve covers and look at the notches in the end of the rocker shafts. They should be facing straight up. The notches are at the front on the drivers side and at the rear on the passengers side. Mopar now sells the rockers, shafts, and stands as a pre-assembled package.
Posted By: Blown71X

Re: 06 3.5L noise?? - 06/23/11 05:57 PM

The shaft pins are not the only thing to look for, I have seen several lately that have worn the rocker into the holddown and make similar noise, this set is off of a 16,000 mile one.
You are pulling the valve covers either way, pay attention to the rocker to holddown, in the picture the left side of the holddown is fine, obviously the right is not.

As was stated they come as assemblys but beware you can still get indivdual pieces....you DO NOT want to screw with it, removing the pins in itself is a disaster waiting to happen.

Rick

Attached picture 6696795-3.5_rocker-wear.JPG
Posted By: 1E2C

Re: 06 3.5L noise?? - 06/24/11 03:31 AM

Well, you guys had me worried, but rocker issues was my biggest fear to start with. Anyway, in accordance with the KISS (keep it simple, stupid) theory I did start with the basics when I got a chance to play tonight. Pulled the serpentine belt and fired it up, the noise is gone. Neither idler nor the tensioner seemed very bad, but it appears one of them is the issue. Lots cheaper and easier, need to get some parts tomorrow.
Thanks all,
Mike
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