Intermitent kocking
Thread Starter
7th Gear
Joined: Dec 2008
Posts: 7
Likes: 0
Intermitent kocking
I have a 1996 Silver Edition Corvette, LT4 automatic with 90,000 miles. I have the car regularly serviced and is in excellent condition. Yesterday, when I started the car I heard an intermittent clicking/low knocking sound. There is no grinding when I start the car and all fluid levels are where they should be. It is more persistent on lower RPMs and when the car idles and gets muffled on higher RPS. There is no spark misfire. It sounds like perhaps a bearing problem??? I initially thought it may be the catalytic converter. The rocker arms/pistons look fine when I removed the head covers. The computer module in the car shows no malfunctions. Without tearing down the engine I am looking for any suggestions. It has been difficult trouble shooting this problem and any suggestions would be appreciated!! Thank you!!
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I have a 1996 Silver Edition Corvette, LT4 automatic with 90,000 miles. I have the car regularly serviced and is in excellent condition. Yesterday, when I started the car I heard an intermittent clicking/low knocking sound. There is no grinding when I start the car and all fluid levels are where they should be. It is more persistent on lower RPMs and when the car idles and gets muffled on higher RPS. There is no spark misfire. It sounds like perhaps a bearing problem??? I initially thought it may be the catalytic converter. The rocker arms/pistons look fine when I removed the head covers. The computer module in the car shows no malfunctions. Without tearing down the engine I am looking for any suggestions. It has been difficult trouble shooting this problem and any suggestions would be appreciated!! Thank you!!
Change the serpentine belt.....yes -- I know it sounds silly....the belt may have streched too far and the tensioner is tapping on itself at low RPMs and creates a knocking noise....as engine RPM increase the belt deflects and makes the tensioner move towards a more loaded postion away from the tensioner's stop so the noise goes away.
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
My 2 cents:
Change the serpentine belt.....yes -- I know it sounds silly....the belt may have streched too far and the tensioner is tapping on itself at low RPMs and creates a knocking noise....as engine RPM increase the belt deflects and makes the tensioner move towards a more loaded postion away from the tensioner's stop so the noise goes away.
Change the serpentine belt.....yes -- I know it sounds silly....the belt may have streched too far and the tensioner is tapping on itself at low RPMs and creates a knocking noise....as engine RPM increase the belt deflects and makes the tensioner move towards a more loaded postion away from the tensioner's stop so the noise goes away.
This is true, it could possibly be your idler pulley itself. Other items could be a lifter or even worse a wrist pin.
