I have a 96C Chevy stepside Cheyenne show truck. Obviously 5.7 engine, via title.
I use 10w30 PUP, or PPHM, basically swap between each change, every 5k miles, or 6months.
At cold idle/start, with it being 80-100 degrees outside, I get about 75psi. Once warmed up about 55-60 at 55-75mph. And idle at around 40. Always been that way since I bought it restored 8yrs ago.
Sometimes I use a 0w40 or 5w30, if it's abnormally cold winters, but see no difference, maybe a few psi in either direction.
My concern is I notice a lot of other 96-98s that I have in the family or know of read about 45cold idle 25hot idle, 40-50 Highway.
What has me even more puzzled my own 99 GMC slt Suburban same engine, I had redone is in the same 25 idle 40 Highway range. Which sees the same oil.
BUT! On the 96, I also notice a oil film in the air intake boot. And oil inside the air tube that leads up to it, not the one with the pcv valve, the opposite one on the passenger side. And my Valve covers always seem to keep a oily mist on them that collects dust. And this is not the case on the 99 dry as a bone.
Only mods on the 96 are, a coolant filter kit, a power steering filter kit, and a power aid intake. With a DRY filter no oil. With a built up 4L60e trans, and true duel exhaust, Magna flow cats.
Things that have been ruled out are, all gaskets, and pcv valve, all oem or better, example being the updated felpro steel lower intake gasket set.
So I'm pulling my hair trying to figure this out. Any ideas you have are welcome. Only thing I can figure is maybe a high volume oil pump was used, as this is common on SBC rebuilds, but I don't see how a at most 15-20% increase in pressure from the pump would cause this. But maybe I'm wrong.
Thank you in advance for any ideas you might have, all ideas are welcome.
I use 10w30 PUP, or PPHM, basically swap between each change, every 5k miles, or 6months.
At cold idle/start, with it being 80-100 degrees outside, I get about 75psi. Once warmed up about 55-60 at 55-75mph. And idle at around 40. Always been that way since I bought it restored 8yrs ago.
Sometimes I use a 0w40 or 5w30, if it's abnormally cold winters, but see no difference, maybe a few psi in either direction.
My concern is I notice a lot of other 96-98s that I have in the family or know of read about 45cold idle 25hot idle, 40-50 Highway.
What has me even more puzzled my own 99 GMC slt Suburban same engine, I had redone is in the same 25 idle 40 Highway range. Which sees the same oil.
BUT! On the 96, I also notice a oil film in the air intake boot. And oil inside the air tube that leads up to it, not the one with the pcv valve, the opposite one on the passenger side. And my Valve covers always seem to keep a oily mist on them that collects dust. And this is not the case on the 99 dry as a bone.
Only mods on the 96 are, a coolant filter kit, a power steering filter kit, and a power aid intake. With a DRY filter no oil. With a built up 4L60e trans, and true duel exhaust, Magna flow cats.
Things that have been ruled out are, all gaskets, and pcv valve, all oem or better, example being the updated felpro steel lower intake gasket set.
So I'm pulling my hair trying to figure this out. Any ideas you have are welcome. Only thing I can figure is maybe a high volume oil pump was used, as this is common on SBC rebuilds, but I don't see how a at most 15-20% increase in pressure from the pump would cause this. But maybe I'm wrong.
Thank you in advance for any ideas you might have, all ideas are welcome.
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