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The dreaded LS chirp


cstmg8

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After setting for about a week, I got in to drive to work this morning and there is a constant chirping coming from the motor. Sounds like it is coming from the drive belt area but does not sound like a belt squeaking. I have not had a chance to open the hood yet, I will do so when I get home. I know that chirping is a common issue on LS motors, any suggestions as to the usual suspects?

BTW, the chirping of course increases with RPM's.

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Thanks Jones

Hmm, I'll grab a belt, probably due anyway.

Strange, I just pulled in to pick up chinese take out and the chirping quit just before I got here.

A/c on, a/c off, seems to make no difference. But now no chirpy??? Perhaps more resistance on the water pump from the thermostat opening?

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Mine also made this noise while decelerating from higher rpms, which ended up being a blown exhaust manifold gasket.. probably doesn't help you with your problem though.

 

 

 

 

Here's a vid of both the chirp and exhaust leak, which again doesn't help you.. I just like posting videos.

 

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I believe it's the very slight rust build up on a smooth-side pulley. I can't remember which accessory it drives but once the rust is "polished" away, the chirping is gone. I assume 00 steel wool would take care of the problem.
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Check your belt tensioners too. I'm about to replace the tensioners for the second time in 3 years on Brian's old WS6. Brian, I still have to tighten those header bolts every 6 months. She's got 95K miles now and still running great. We both still love the car and glad we bought it off ya. If it was only a 6spd. lol
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It would still be in my garage haha..

 

I knew you was going to say that.. haha

 

So is it still chirping when cold?

 

Yep, it's doing it again only now it's doing it hot or cold. Not sure if its the cheap Autozone parts I used or if there's something out of alignment with the belts causing them to go bad.

 

Do you know if the rocker arm trunnions was ever changed in that motor?

 

OP, sorry for the hijack:)

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Do you know if the rocker arm trunnions was ever changed in that motor?

 

I bought it with 49k miles and I never changed them. I doubt the previous owner did either. He bought it from a dealership owner's son (who sold it to him after like 3k miles). Why do you ask?

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There is some GM Bulletin out there about having to line up accessories with an F'ing laser if you replace anything. Have you replaced anything? A/C or water pump or anything?

 

I've been through 2 upper and 1 lower tensioner on our Tahoe, but that was more of an annoying hum than a chirp.

 

Good luck.

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The trunnions should not need replaced at 49k miles, or even 100k miles.

 

BTW, ditch those header bolts and go with stock exhaust manifold bolts.

 

Whats the warning signs of the trunnions taking a shit on me?

 

Also, maybe a dumb question but is there a difference in header bolts and exhaust manifold bolts?

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The trunnions are needle/roller bearing assemblies that the rockers use to pivot. If they start going out, they'll make grinding noises, you may have valvetrain related noises/binding/issues, or the bearings will get swallowed by your valves.

 

As for this laser alignment, I've never heard of nor needed to utilize such on any of my LS engines, even after accessory replacement. Must be something new.

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I haven't replaced anything, but I would like to figure it out because it sucks to have your "nice" car sound its about to rattle apart lol. If it were the 4runner I would just drive it.

After some research on the g8 forum, it looks like there is a belt throwing issue with a bad tensioner, and I definitely have the crank pulley wobble. I may go ahead and get the new tensioner design from Aus, and pick up an under drive pulley from Jegs.

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