5.3 oil pressure... too high?

[jks67ss396]

Hey guys

I took my first long freeway trip with the 71 with the 5.3/4l60 installed.

love it! and decent power

but, im trying to understand my oil pressure.

the truck was originally a 292 I6. My understanding is that the stock oil pressure gauge for I6 and sbc is 0-60psi and for the bbc 0-80

So. at idle warmed up, its about halfway up the gauge/dead center. so Im taking that to be 30 psi

at 2000 rpm/cruising freeway, im at about 45-50

at one point, i kinda got on it to pass a slow moving car and the gauge went over to full range. im assuming thats 60 psi

Ive always thought that is supposed to be around 10psi/1000 rpm

Id say passing, i got up to 4000 rpm, definitely not higher than that.

So im wondering if my oil pressure is a little high or if thats normal for these 5.3Ls.

my engines got about 75k miles on it, so its not new

thoughts?

what about you guys... what are you seeing at idle/cruise/passing?

thanks!

[crazy longhorn]

I would not bet on that stock guage? I run auto meters in my truck....the old 5.3, with 140,000 , on the clock runs 40 psi @ idle (hot, 200-205 on the temp)....stepping into the throttle , she will go 52-55 psi..... Longhorn

[truckdude239]

Mine runs 40 at idle 55-60 at 2500 or higher rpms

[Indian113]

When my motor is at running temp it idles at 45 then climbs as speed picks up I have never seen anything higher than 55 though.

[jks67ss396]

and can you guys confirm that the stock I6 and sbc oil gauges max at 60psi?

thanks!

[Blackpony]

My ls1 runs around 45-50 idle hot and 75-80 revved up.

[Big Port Jimmy 6]

Mine pegs the 0-60 gauge. but I have a high pressure LS6 pump. Jay

[ls1nova71]

60 psi guage is stock, as far as I know only the C60s ever came with 80 psi guages. My stock 5.3 will peg the stock guage when really stepping into it. The 10psi rule is just a minimum, and not even sure how accurate that is. I wouldn't worry about it.

[cableguy0]

Trusting a 40 year old gauge is iffy at best. They weren't completely accurate in the first place but it just sounds like you have a nice healthy engine with good oil pressure. The only time I would worry is if you were over 80psi.

[BR3W CITY]

If its over 20 and under 85, and the truck is still running...your fine.

[jks67ss396]

sounds like i might want to get a stock looking 80psi gauge just to make sure, but i think im fine

[mmiddle]

Originally Posted by BR3W CITY

If its over 20 and under 85, and the truck is still running...your fine.

Good rule of thumb for any engine

[BR3W CITY]

Originally Posted by mmiddle

Good rule of thumb for any engine

I have yet to melt one down yet lol.

As a note to anyone worried about the constant change of OP during use; I understand that many import cars and small american cars run a very small range of steady oil pressure, say 50psi. Our cars won't do that, nor should they be expected to. Its not unusual to see your o.p change, and respond to changes in rpm etc.
Some folks will also say that the changing o.p can be a result of worn out impellers or a leaking oil pump. While its possible, this really isn't the case on most late models. Again, a reasonable sweep in pressure is completely normal on a fully warmed up ls engine, especially if going to higher rpms. Its a mechanial pump, and like any other fluid pump (ps, coolant) it will move more liquid at higher rpms. Since the fluid is viscous and pumped through restrictions, this means pressure.
Also keep in mind that the type of oil, ambient temp, condition of the oil and volume of oil all effect oil pressure. Plenty of beat down, loose-ringed 350's will still put up 65psi at startup on a cold day, but may fall to dangerously low 10-15psi. A pushrod engine will still run on only about 10psi o.p, however the oil dependant valvetrain components may not function as they should.

Lastly, consider HOW the OP is being read. Mechanical gauges are likely to show the continued fluid changes in OP as you drive. Once your used to how your engine reads out on the OP gauge, its easy to tell if anything abnormal occurs. They are vulnerable to pinched lines, restrictions, or air in the line all causing bad readouts.
There are those that use a digital gauge with a sender. They can be "twitchy" if the connections aren't good, and the sender has to match the resistance sweep the gauge expects. They are pretty reliable, but the sender issue means a "working" gauge could be showing false results if paired to the wrong sender.
Then you have the LAN gauges, BCM controlled gauges, HUD type gauges, and high-end aftermarket stuff. These will use a bcm, control box or other type or processing unit (or in some cases the ecm) to get the signal to the gauge. Instead of the sending units that connect directly to the gauge, these sending units give an input value to the computer. The computer then reads/interprets the input value and sends an output value to the gauge. This is also what is often responsible for the "static" oil pressure that in many imports and small latemodel us cars. When the computer see's the value, it can buffer/average/interpolate the data much like we're used to seeing in the "Lie-o-meter" for MPG. This means that the 50psi the gauge or hud are seeing, could actually be a fluctuating value. Often, the refresh rate or sampling rate is fairly low. This means a car having rapid changes in o.p, would still appear to have static o.p. I haven't spent much time in the GEN IV/V stuff, but I know the ecm does get an oil pressure value, so I'm curious if its GM lan gauges use a buffered value or a direct input.


Wow, that was never meant to be so long.