you got a lifter thats bleeding off its pressure. gm says as long as it stops in a minute or so its fine.

my old engine would do this right about 3,000 miles after its last oil change. so i started to run a mix of 40 and 30 weight oil (3 of 40 and 2 of 30) and it hardly ever did it again.

you could run 40 weight too. like 10 w40.

if you used 5w30 thats more of a winter oil, so once its hot its thinner. and its been nice and hot out here lately in the NE.