Q: Loud chirping from valvetrain

asked by on December 22, 2016

Have a loud chirping sound coming from cylinder number three. I know this issue isn't belt related because an engine compression test revealed it has between 60-80 psi while cranking compared to 150 on all other five cylinders. Could it be a valve not seating properly? Need some advice moving forward with a plan of action.

My car has 212000 miles.
My car has an automatic transmission.

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Hello, thank you for writing in. There are several causes for low compression. It was a great idea to test all cylinders. With only having low compression in one cylinder, the issue is likely an exhaust valve. The vehicle should have no more than a 10% difference in compression across all cylinders. Your other cylinders are right on the point, needing to be between 140-160 PSI as a general rule of thumb. From here you are going to need to do one of several tests to determine if the issue lies with the piston ring or the valves. For more help isolating the failed component, you may contact our service department to set up an appointment at your home or office.

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