Not ussually posted by scottmt21 on August 16, 2012 at 03:53 PM
Message
Yes lifters. They are hydraulic so when they get clogged up or if oil gets thin they can make a loud tapping sound kinda like rod knock. It would be louder at idle due to lower oil pressure. When revved up oil pressure increases wich will quiet it up. It is a stretch but it sounds like he is deperate to find a possible reason not to pull motor. Hey it cant hurt to check it out first! Lol