coolnick

I have a bone stock (well, not anymore...) 05 CTS-V with 93k miles that developed a loud chirp noise at idle to 1500 rpms or so. It sounded like it was coming from the serpentine belt and with the mileage I figured it might need a new belt. When I removed the belt I found some play in the tensioner pulley, so I replaced that along with the belt.

I started the car and the chirp was still there. I then took out my trusty harbor freight stethoscope and began checking all the accessories. The noise appeared to be coming from the power steering pump, so I ordered one of those. Just before installing, I decided I had better do a sanity check. I removed the serpentine belt and started the car. With no belt on the car I still had the chirp, in hindsight this should have been the first step. I quickly returned the PS pump.

I grabbed the stethoscope and began listening again. The noise was definitely coming from the driver's side towards the rear (it had sounded like the PS pump earlier because the PS bracket is bolted to the driver's side head and I was only checking accessories and their corresponding brackets). I removed the valve cover and started the car. You can do this without making a massive mess if you stuff some rags on the low side of the valve cover opening. With the stethoscope I listened to each rocker and determined that the noise was coming from the #7 (farthest back) cylinder. I could not tell if it was coming from the exhaust or intake rocker, so I decided to swap both of those rockers with the #1 cylinder rockers.

The noise stayed in the #7 cylinder. At this point I knew I had to pull the heads to investigate further and was hoping it was only a lifter. This is my only car so I had to order parts ahead of time hoping that I could tear it down and put it back together in one weekend. I went ahead and ordered a full set of new LS7 lifters and trays, all the gaskets and new timing chain from Texas Speed and a TR TruTorq level 3 cam with springs and pushrods from another V owner on this site.

And this is what I found when I pulled the head:


I have never been so happy in my life to find a failed part. When I removed the cam I found a similar mark on the #7 intake lobe. This seems to be a fairly common failure on this older style lifter. I won't get into what I think the root cause would be, but in my case this was a bone stock car that rarely saw a beating and has been properly maintained.

I just thought I would share my experience, as this was the first place I searched and I found a lot of different threads on the dreaded chirp. If you are experiencing a loud chirp that sounds like lifter tick, minus the tick, I would immediately pull the serpentine belt and see if the noise goes away. From that point you will be able to make a much more accurate diagnosis without throwing parts and money at the car in hopes that it cures itself.

Thanks to all the other threads on this forum and thanks to my ricer friends on my other ricer forums.

joecar

Thanks for sharing

dr_whigham

iTrader: (49)

Dude, this is a REALLY good thread. I have 140k on my car, and am about to cam her. I'm really thinking about just pulling the heads as well and doing the lifters now as well.

I'd hate for a lifter to ****-the-bed on me and destroy a brand new cam.

Thanks for posting this.

coolnick

Pulling the heads is one of the easier procedures on these motors, I would not hesitate to do it if I were you. That is exactly why I replaced all 16.