Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hi, My Name is ***** ***** for posting your question to just answer. I am a ASE Certified Master Auto Technician with 20 years experience. I am confident we can resolve your problem together.Please remember I don't know your skill level. I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies to get to a satisfactory resolution.I also try to give all of the information you may need expecting a positive rating.
How did you determine it has a burnt valve? did you use a vacuum gauge?
The lean condition typically cannot cause the knocking sound. Because your vehicle has Variable valve timing it is not unheard of for the lean condition to make a knocking noise. Likely the cam actuators knocking. I would reseal the intake and try again before going in to far. Problem is the lean condition may have contributed to a burnt valve.
Get a vacuum gauge and check your vacuum while idling. If the needle is nice and steady there is no reason to tear apart. If it fluctuates then you will need to tear apart. You should have about 18 in/hg at idle. let me know your results. a vacuum gauge is inexpensive and available at most parts stores. (less that 20 dollars) and will verify if teardown is required.
It has been a couple of days since I have heard from you. Do you still need assistance? I have also noticed that I have not received a rating from you. If for some reason you question did not get answered please reply. I am only compensated for my time when you leave a positive rating. Your understanding is appreciated.