My Tahoe is making a loud tapping noise when the engine is cold. It goes away once warmed up but its getting really loud. I read about noisy lifters/valves and was wondering if additives work? Its a 1996 with over 140,000 miles so I’m not looking to do any major engine work, just make it a little quiter.
What do you have to lose?? There are additive (solvent) products that claim they can free up stuck lifters…Rislone has been around for MANY years, there are others…On many Chevy motors, the valves can be adjusted, compensating for wear up to a point…
Get an experienced mechanic listen to it and confirm what’s making the noise.
Leave it overnight.
It could also be piston slap.