150,000miles unknown records 4X4 chevy Z-71 W/NO maintence book!
i just put castrol 20/50 full sintech oil
what should i be expection to break down internally now??????? what do i do to prevent any down time ? also change the tranny fluid(no flush)looks good.
Just because there's no maintenance book doesn't mean some, or all, the maintenance wasn't done. If you just got this thing, its expectation to break down internally should have been considered before purchase. That said, it's probably ok for a while.
I don't really understand your question. What motor is this? 150k in 6 years is probably at least some easy highway mileage. It won't self-destruct that soon unless random misfortune strikes or the previous owner knows something you don't. If you still have your old oil laying around you can mail it off for analysis from a site sponsor.
Yes you should change your tranny fluid and filter via a pan drop. You should also consider a tranny cooler if there isn't one already. Change your antifreeze. People get hung up on oil when cooling failures kill more motors, and transmission problems send more vehicles to the junkyard.
Unless you have a "real good reason", and living in Texas isn't enough, lose the 20w50 next change. If you want to go "thick" 15w40 is more than plenty.
I would be more concerned about the 4L60e transmission than the motor.
I would drop the trans pan, change the filter, clean and reinstall the pan.
OReily's has the filter and gasket for $10.
Change the trans filter, and refill, then drain the pan and refill at the next couple of OCI's.
Use Lubeguard for good measure.
20/50 is to "heavy" for the 350 with summer approaching.
I would Seafoam the motor, then change the air filter, fuel filter, PCV, plugs, cap and rotor, and plug wires.
When you seafoam the motor through the PCV, run a half bottle of Seafoam in the crankcase and let idle for 10-15 minutes. Drain, and refill with 10-30 or HD 30 and use a new AC Delco filter.
The I would hit the rear diff, and transfer case. with drains and refills.
Finally, I would change out the radiator fluid, refill, and use a bottle of NAPA Kool.
Finally, suck out the old power steering fluid and brake fluid with a turkey baster and refill. Do this twice in one week (clean or use different basters).