Have a 5.7 , good oil pressure running, no noise, but on start up, lifter clack...obvious drain down symptom....any one had luck with additives that will reduce? Thoughts? I really do not want to pull the engine apart to replace lifters...
Dan

Could be oil bypassing camshaft. How many miles on it? What year?

We have an ole saying for those 350 engines that rattle at startup. That'* the heartbeat of a Chevrolet. lol. All kidding aside, Ive had good luck with Rislone. Add one quart to 4 quarts of oil. Im assuming you have good oil psi.

Thanks guys! The truck is a K3500, 1997 version...has 85k in miles and has been taken care of most of its life. The 5.7 has been strong with only occasional issues with injectors plugging up bc of poor fuel we are getting. The rattle is more annoying than anything, but any clearance is not a good thing when it comes to cam/lifter. I will give Rislone a try.

What'* your oil pressure?

start up, 55 pounds, hot 45 pounds

Good numbers.