Hello All, I have a question pertaining to my 2002 Blazer. It is making loud clicking noise at start up and lasts for 30 seconds and then goes away. Any Ideas to what it may be? I was thinking it maybe a lifter sticking, Or one of my friends said it could be the A.C. Unit needing fluid. Any help will be appreciated.

 

Possibly you might be hearing pcv valve clatter ?
Btw, my lifters clattered once when I first bought mine, after oil change, it's never happened again.

 

i would say lifters. try a differ brand oil filter, i like wix napas are wix. have a good drain back vavle so overnight the oil wont run back and aeroate the system. a bottle of stp treatment in the oil will help too if a lifter is weak, becoming a little common on these especiallt if collant has gotten into the oil, check that too.often