How to Deal with Abnormal Noises from Valve Tappets?
3 Answers
There are three main methods to address abnormal noises from valve tappets: 1. Valve leakage noise: Typically occurs outside the valve chamber, more noticeable under high load and low RPM conditions, with the noise intensifying as the load increases. The solution involves removing the cylinder head, lapping the valves, checking the valve spring tension, and readjusting the valve clearance. 2. Valve tapping noise: During engine idling, a continuous tapping sound occurs between the valve stem end and its driving component. The remedy is to readjust the valve clearance to the engine's standard specifications. If the locking nut on the adjustment screw is loose, it should be securely tightened. Severely worn components should be replaced, and broken valve springs must be replaced promptly. 3. Valve seat noise: Caused by seat ring detachment, rough valve seat surface, or substandard machining precision. The solution is to reinstall the valve seat according to assembly specifications, ensuring the upper surface is flush with the body plane and any protruding parts are ground flat.
As a mechanic who has worked on numerous engines, I've encountered quite a few cases of valve lifter noise. When dealing with it, you need to follow a step-by-step approach: First, start the engine and listen carefully to pinpoint the exact location of the noise to confirm if it's indeed the lifter causing the issue. If the lifter is confirmed as the source, check for any looseness or signs of wear, and gently pry it with specialized tools to see if it's stuck. If dirt or debris is causing the blockage, remove the lifter, clean it thoroughly, and apply high-temperature grease before reinstalling. If the noise persists after lubrication, consider replacing the lifter. Don't overlook the oil system, as lifter noise is often related to insufficient oil pressure—check the oil level and quality to see if it's too dirty or has inadequate viscosity, and change it promptly if needed. After the repair, take the car for a test drive to monitor any changes in the noise and ensure no other components are affected. If you can't resolve it yourself, visit a professional repair shop early to avoid prolonged damage to the valves or even the entire engine. Regular checks of the oil and valve system can significantly reduce such issues.
Having driven for many years, I've personally experienced the issue of tappet noise several times, and the solution isn't complicated. First and foremost, for safety, check the engine oil condition after parking—low oil pressure often causes the noise, so ensure the oil level is in the middle of the dipstick, and replace the oil if it's aged. Next, inspect the tappet area, carefully cleaning any accumulated sludge or debris, being gentle to avoid damaging surrounding components. I usually apply a small amount of high-viscosity oil as a temporary lubricant to test if the noise subsides; if not, the tappet components need replacement. Remember to also check the valve rocker arms and camshaft, as linkage issues can indirectly cause noise. After repairs, test-drive to confirm the noise is gone, and for long-term maintenance, check the oil quality every 5,000 km to prevent recurrence.
