# Weird knocking noise..



## lasoya113 (Mar 19, 2011)

Hey everyone I have a a issue with my 06 GTO. About few months ago I installed a cam,fast intake manifold,headers and exhaust. I then recieved a HP tuner and started to work with it to tune my car. Shortly after that I started to hear a weird knocking noise coming from under the motor. Its not very loud but it does get faster when I raise the rpm's. The first shop I took it to put it up on the lift and tried to pin point the noise but they couldnt. I then took it to a engine performance shop and they said it didnt sound like a a lifter or anything in the valvetrain. They couldnt figure it out either because it stays the same no matter if the car is cold or hot and its been making the same noise for months now and nothings changed. The performance shop didnt put it on a lift but they thought it might be in the trans but when I pushed in the clutch nothing changed so they went back to thinking its in the lower part of the engine. The noise isnt extremely loud but its loud enough to get my attention. Theres no loss in power and like I said before its been like this for awhile and its been the same. I took a video of the noise but Im having issues posting it so I will just put the link to it below. Any suggestion will be appreciated. Thanks
http://www.youtube.com/watch?v=bwgjUb_l2mE&feature=youtu.be

Oh I also want to add that the car only has 23,000 miles on it..


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## lasoya113 (Mar 19, 2011)

Anything?


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## GTO JUDGE (May 14, 2005)

Was it ruled out the cam is NOT thumping something as it turns. i.e. not enough clearance and it hits as it rotates? Or any other parts doing the same from internal clearance problems? Did the outfit that performed the modification take an internal look to see what gives? If something is hitting it will leave evidence. IMO: it may be running ok now just making a thumping noise, but down the road more than likely a failure will occur from wear or breakage from a possible obstruction.


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## SRT LOL (Dec 1, 2011)

I had the same issue after a cam swap.. After a few thousand miles it got loud out of nowhere. ended up being a broken rocker arm. Wait for it to completely fail, if it was your bottom end, you'd for sure hear it screaming at you


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## lasoya113 (Mar 19, 2011)

The problem is that you cant really hear the knock from the top. Its sounds like its coming from the bottom. I took it to the dealer yesterday "wed" to see if they could find the problem but there having issues finding it. They are taking the valve covers off tomorrow and checking the valvetrain when the car is running. I really hope they can figure it out. If anyone else has any ideas I would appreciate it. If they find out whats wrong Ill post it. Thanks


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## GTO JUDGE (May 14, 2005)

lasoya113 said:


> The problem is that you cant really hear the knock from the top. Its sounds like its coming from the bottom. I took it to the dealer yesterday "wed" to see if they could find the problem but there having issues finding it. They are taking the valve covers off tomorrow and checking the valvetrain when the car is running. I really hope they can figure it out. If anyone else has any ideas I would appreciate it. If they find out whats wrong Ill post it. Thanks


Only suggestion I have is DON'T drive it until its diagnosed and repaired.


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## lasoya113 (Mar 19, 2011)

Update: I took the car to the dealer and all they told me was they think they can hear the knocking noise coming from the number 6 cylinder. I took the lifters out and took the heads to a performance shop over here and we couldnt find anything wrong with the lifters, springs, or pushrods. I went ahead and bought a new cam, lifters, pushrods, and dual valve springs. Im installing everything right now so if the noise is still there after Im done then the knock has to be in the bottom end.


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## lasoya113 (Mar 19, 2011)

So after replacing my lifters, valve springs, cam, and oil pump and also a tune I still have the knocking noise. Im stumped on what the noise is. It starts knocking after about 15 sec after I start my car up in the morning. also no one seems to know what the noise is. The knock hasnt got louder or worse and ive drove my car for about 10,000 miles since the noise started. Does anyone have any idea what it could be? thanks

http://www.youtube.com/watch?v=bwgjU...ature=youtu.be


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## 06-GTO-SLP-Bobcat455 (Nov 8, 2018)

Was this issue ever resolved?


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## Beeroni (Oct 4, 2021)

lasoya113 said:


> So after replacing my lifters, valve springs, cam, and oil pump and also a tune I still have the knocking noise. Im stumped on what the noise is. It starts knocking after about 15 sec after I start my car up in the morning. also no one seems to know what the noise is. The knock hasnt got louder or worse and ive drove my car for about 10,000 miles since the noise started. Does anyone have any idea what it could be? thanks


Any update to the knocking noise?


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## An0maly_76 (Dec 25, 2021)

Exhaust leaks can sound like a knock sometimes. Another possibility is a cracked or warped flexplate (sits between crankshaft and torque converter, has a ring gear used by the starter). I have seen cracked ones rattle to the point they sounded like a rod knock, and had one warp on a TH350 once that sounded for all the world like a serious knock. Turned out one segment was smacking the block as it spun.

Try this -- take a piece of pipe, and touch it to any non-moving parts in the area. Folding your earlobe and putting to the pipe will help isolate ambient noise. The louder it is, the closer you are to the source.


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## Beeroni (Oct 4, 2021)

I had similar issue to laysoya113 above..started with ticking noise on my '06 GTO after running it pretty hard. Turned out to be a failed oil pump and stuck/broken lifter. It chewed up the cam. My shop changed out the high flow oil pump, replaced LS7 lifters, new cam..then still knocking. Next they check the rod bearings and sure enough they were bad. Seems metal got down in the pan from the partially broken lifter and/or engine ran starved of oil just enough(which was not long at all)since the pump took a dump on me. So long story longer.. had to rebuild the darn thing with new Clevite rod and Main bearings, crankshaft journals polished and now going back together.


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## 1st2004gto (Dec 15, 2021)

I would take a look at the oil? Cut open the the oil filter and look for metal particles. It's possible something dropped into the motor through an oil drain hole when the motor was apart. It could have damaged the rod bearing of the number 6 cylinder. Disconnect the plug wire to #6 and see if the noise goes away. Try the other cylinders also.


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