Everything posted by Jon Goyette
James, Thanks for the reply. The 4.3 is basically a Gen 2 vortec, 5.7 flat tappet engine with 2 cylinders lopped off. My 1st thought was oil pump, pickup, tube or screen. but then I thought if there was a blockage it would have to be on the post pump side of the oiling system to cause the increase in pressure. This lead me to think it was the ticking lifter that was the cause, even though I can't really wrap my head around that due to the symptoms. Looks like I will dive into the lifters, probably about due to put a new spider on it anyway. Should probably pull the pan and go after the oil pump too just to be safe...and why not do a timing set and cam...but thats why I didn't want to get into it in the first place...
I can see a bad lifter causing a drop in pressure, but would it cause an increase too? When the engine is operating in "no tick" mode, oil pressure tops out at 45psi and is steady regardless of rpm. In "tick" mode, oil pressure increases to 65 at higher rpm and drops to 15 at idle. You think a bad lifter is the culprit? Not trying to be a dick here, just want to verify the issue before replacing parts. Thanks for the input.
Here's an issue that has me stumped. 2000 Silverado, 4.3, 200K mi. Truck runs great, no oil consumption. I have a very random oil pressure fluctuation, normally I have 40 psi (+ or - 5psi) pretty steady, not affected by rpm or temp. about 20,000 mi. ago I started getting a lifter tick on start up accompanied by crazy fluctuation in oil pressure relative to rpm ( 15psi at idle and 60+ at 3500) It will do this for maybe a week and then stop....no tick and steady oil pressure again. Truck has always had regular oil changes with quality oil (dino) and a Wix filter, I've tried Lucas oil additive, Marvel, different viscosities between 10-30 and 15-40 nothing makes it worse or better. Seems to go away by itself and then return completely at random. Sometimes it will go 5k with no issues, other times maybe 2k. Not affected by oil changes or mileage...just comes and goes. Always lifter tick and oil fluctuation....tick goes away and so does crazy oil pressure. WTF is going on?
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