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"Chirp" sound under heavy acceleration


lothos

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Hello all. This board has been a great resource in the five months I've had my 1995 STS.

I'm getting a chirping sounding noise from the front end under heavy acceleration. It happens around the time the rpm's redline and shift. The only code I have is a P076 tranny pressure control solenoid. I've done the shift solenoids, and the tranny seems pretty strong.

The noise sounds a little bit like chirping the front wheels, but I don't think that's the source of the noise. It's short, and only lasts for a second. It seems to be coming from the right front end, and I noticed some irregular tire wear on that tire. The tread on the outer side has a strip that is worn down more than the rest.

Could this be a ball joint possibly? I've replaced the driver's side but not the passengers side. Or am I looking at an issue with the transmission? I'm not a mechanic by any means, so any suggestions are much appreciated.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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Turn off the HVAC system off and see if you still get the chirp. I'm betting you dont.

I get it whenever the AC compressor turns on.

Not sure how to fix because it has not bothered me enough. Probably a good time to find out now.

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both my wife and kid commented that the car was chirping or buzzing. it seemed to only occur under fairly heavy acceleration. i pulled the motor last summer for headgaskets and found the front motor mount was separated. i put in a new mount and the sound seems to have been greatly lessened. i think the motor was shifting and allowing something to rub. maybe the serp belt pulley on the frame rail? or the rear valve cover rubbing against the firewall? sounds like possible motor movement to me.

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Turned the heat off, and hit the gas a couple times. The noise is gone.

MAC's suggestion made sense, because I remember now hearing a rattling noise when the car was parked with the engine on. It sounded like a chain rattling, so a loose tensioner or something would make sense?

Not sure what to think now. I burst a metal coolant heater line a couple months ago, and the mechanic replaced the metal lines behind the engine next to the firewall and the rubber hoses back there. At the time he told me that there was no refrigerant in the system. Could that be related?

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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I was searching the forum for more information and it sounds like it might be the AC compressor clutch?

http://caddyinfo.ipbhost.com/index.php?sho...71&hl=chirp

That thread mentions a rattling sound as well.

Would that make sense, especially since the noise is gone with the HVAC off?

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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But the noise disappears with the HVAC off. And I remember hearing a rattling sound before. Could it still be the belt if the noise is gone with the HVAC off? Or would that point more towards the AC clutch? I'll have to take a look when the weather warms up more.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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But the noise disappears with the HVAC off. And I remember hearing a rattling sound before. Could it still be the belt if the noise is gone with the HVAC off? Or would that point more towards the AC clutch? I'll have to take a look when the weather warms up more.

Because it's possible with the heat on (particularly if you have the temp. control on 'AUTO' since the A/C will kick on to regulate temperature) the extra torque needed to run the compressor is placing sufficient resistance on the belt to cause it to slip under hard acceleration. When the compressor is not engaged the belt is not under resistance since it's spinning on the hub bearing only. This is what I view as a possibility, not necessarily what is actually happening.

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I still had the heat off on the drive to work this morning, and I got the belt chirp noise again. I'll take a look at the belt and tensioner, etc. this weekend when it's hopefully warmer out.

Thanks a lot for the help everyone.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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Given the age of your car, pull the serp belt off and grab the AC pulley hub after taking off the wheel well inspection cover and see if the hub has any play, if those bearings are loose/worn, you will bind up the hub and the belt will slip.

This is a photo of the compressor taken through the wheel well inspection cover, my compressor's pulley bearings went bad, overheated the clutch coil and blew the AC COMP fuse, shortly after that I got smoke coming off the hub and bypassed the AC compressor with a short belt

Here is discussion of how to bypass the compressor with a short belt

<a href="http://caddyinfo.ipbhost.com/index.php?sho...4&hl=bypass" target="_blank">http://caddyinfo.ipbhost.com/index.php?sho...4&hl=bypass</a>

post-2998-1207153458_thumb.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I bypassed my AC Compressor since it was driving me nuts.The chirp !!!!!!!!Aghhhhh !!!!

The only thing other than that is swtiching 1st - 2nd...

My '95 does it with ease on a cold morning....

Hey by the way... "Welcome to CaddyInfo"!

Florin

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I bypassed my AC Compressor since it was driving me nuts.The chirp !!!!!!!!Aghhhhh !!!!

The only thing other than that is swtiching 1st - 2nd...

My '95 does it with ease on a cold morning....

Hey by the way... "Welcome to CaddyInfo"!

Florin

Thanks for the welcome B)

I'll be trying to hunt down the source of the noise some time next week probably, we're supposed to be getting snow for the next couple days.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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  • 3 weeks later...

Haven't had a chance to look at things yet. I thought I'd post an update and see if someone could point me in the right direction.

The sound is kind of like a chirp, but now it reminds me of a turbo charged engine. When you floor it, and the turbo kicks in and gives that "tsss" sound.

It happens with the HVAC on or off.

The belt didn't look too bad but I'm not sure if it's original or not.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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