OIL PSI / BRAND / WEIGHT

[YukonLover]

Hi everyone,

I know oil pressure seems like a common question. But, what I don't understand is the constant variations; especially when there is void of any precursor. I have a 2003 4x4 with a 5.3. I replaced the pump, timing equipment, and pick up tube, gaskets ect. And it ran 35-40 PSI cold or hot idle, and around 45-55 under load. This truck had around 224k.

I have another 2001 2 wheel drive, and when I got it, it idled around 30 PSI cold, and 25-30 hot, and under load 39 PSI. I have been delivering for a company packages 3x a week for several weeks, the truck has been running 8-12 hour days, 80 miles a day and idling with limited start and stops. The oil, when cooled and dropped to the pan is a bit tacky, but not dirty. I maybe burned off at most half a quart since I changed the oil about 1500-1800 miles ago. Just last night my oil PSI seemed to be warm fighting 20-25 PSI sometimes not going past 20-22 PSI, and under load various pressures between 32-39 PSI approximately. Noticing a drop here.

I am getting ready to change the oil, and I did some research and shows that Royal Purple HPS has the most zinc at 1275, most oils are more more than 950. Apparently RP is not API standard, so they can add whatever they want, and their film strength is also superior, as I have seen in several test videos. Im looking for a bit more zinc and some extra film strength to keep it going longer. I was hoping to increase some pressure by having a thicker oil. I was thinking of adding some lucas to my current oil brand. But then I seen the natural lucas thickness, and I said what if I just use that and increased to 5w40 instead of 5w30? I heard a lot of people allege lucas made their bearing tolerances worse, so it improved temporarily, but just made the inevitable happen with just straight weight oil. I ahve been using Valvoline MAXlife high mileage for over a decade, but I feel in this engine maybe its not appropriate.

My plan was to use RP 5w40 and a good quality filter, possible replace the oil sending unit. And then say in 1,000 miles run some marvel mystery through it for another 500 miles, and then do a complete straight RP 5w40 swap until I have to change the pump out. Sound like a good idea?

 

[strutaeng]

Have you watched Lake Speed Jr's videos on oil additives on YT? He's got a lot of excellent videos out there.

I don't remember all of the names and stuff of what's what... because I've since slept, LoL. But I just remember that regular oil changes with quality oil is better than adding additives, which can actually cause bad effects due to the chemistry mixing up. I believe high zinc is only for initial break-in of engine parts like piston rings and such. Too much of it can actually cause catalytic converters to die faster. That's why they reduced the zinc in the oil. Auto manufacturers wanted cats to live something like 200k. I think that's what I read.

I wouldn't worry too much about what your needle is saying, unless it's zero. The cluster isn't even calibrated to "psi", I don't know if you knew this or not...I literally had just mentioned this on another forum. If you really want to know what the pressure is, hook up a mechanical guage.

Just do oil changes based on "severe use," whatever that is.

 

[Marky Dissod]

Why not do a used oil analysis, see what they have to say?
We all got fixated on oil pressure, which is almost too easy to measure, then somehow decided 'more is better'.
Reminds me of wanting and getting more boost, then wondering why the engine isn't making more power.
(Then when he finally learns enough to make more power, he wonders why it doesn't translate to a quicker 1/4mile ...)

More difficult to measure but more important is whether or not oil is getting where it belongs, and moving smoothly through it all.
Once it does that, it carries away contaminants and other stuff, suspending much of it, some of it getting trapped in the filter.

Think you're better off getting a used oil analysis.

 

[YukonLover]

Thank you for the ideas.
I was not aware of the lack of calibration. Although it is not expressly printed on the dash, I assumed GM would have made something close to calibration at least.

I spoke to Royal Purple, Valvoline, and Lucas today. I hate to say this, but I feel Lucas may be pointless. One company said testing showed extra wear on the engine, and the Lucas product essentially warmed up and most if not all of the added viscosity almost quickly disapeared. I used it 10 years ago, and I really don't remember it. Valvoline confirmed the Maxlife BLEND that I have been using has the Zinc ad 790 PPM and the full synthetic at 820PM. Compared to the 800 in royal purple standard synthetic.

Accoding to the PQIA-
Royal purple ZINC is 800PPM, Phosphorus at 690PPM and Boron at 211
Valvoline Max Life Blend ZINC 887PPM, Phosphorus at 765PPM and Boron at 186

I have seen videos where Royal Purple is just superior on film strength though, how and why?
can our 5.3s take a 5w40? how much PSI wold increase by a thicker oil ?

I ordered an oil test kit a while back waiting for this moment.

 

[strutaeng]

Thank you for the ideas.
I was not aware of the lack of calibration. Although it is not expressly printed on the dash, I assumed GM would have made something close to calibration at least.

I spoke to Royal Purple, Valvoline, and Lucas today. I hate to say this, but I feel Lucas may be pointless. One company said testing showed extra wear on the engine, and the Lucas product essentially warmed up and most if not all of the added viscosity almost quickly disapeared. I used it 10 years ago, and I really don't remember it. Valvoline confirmed the Maxlife BLEND that I have been using has the Zinc ad 790 PPM and the full synthetic at 820PM. Compared to the 800 in royal purple standard synthetic.

Accoding to the PQIA-
Royal purple ZINC is 800PPM, Phosphorus at 690PPM and Boron at 211
Valvoline Max Life Blend ZINC 887PPM, Phosphorus at 765PPM and Boron at 186

I have seen videos where Royal Purple is just superior on film strength though, how and why?
can our 5.3s take a 5w40? how much PSI wold increase by a thicker oil ?

I ordered an oil test kit a while back waiting for this moment.

https://www.silveradosierra.com/threads/oil-pressure-issues.768412/#post-7510672

Post #5....is what I was saying...

I will try to find the Lake Speed Jr's videos I was talking about later today...I think it will surprise you if you haven't seen it about "oil additives"...

 

[YukonLover]

Did the 2001 XL have an oil cooler? I know my 2003 does

 

[strutaeng]

Engine oil cooler was more like a towing RPO code option. Not related to year or another...

You can always just add one too.

 

[strutaeng]

Here's a link to the video and discussion on tbe topic: https://www.tahoeyukonforum.com/threads/lake-speed-jr-oil-additives-snake-oil-video.148337/

 

[Marky Dissod]

Thank you for the ideas.
I was not aware of the lack of calibration.
Although it is not expressly printed on the dash, I assumed GM would have made something close to calibration at least.

Even if that assumption were true, my '02 Tahoe now idles at operating temp @ 360RpM ...
... at least according to my tachometer's needle, which has clearly escaped its original tolerances.

Can't wait until a fully digital / non-mechanical dashboard replacement becomes a thing ...

 

[PPV_2018]

I wouldn't worry too much about what your needle is saying, unless it's zero. The cluster isn't even calibrated to "psi",

Wait a minute.. So then what is it calibrated to? Even if the dummy gauge as i call them are not entirely accurate.. which i never truly believe they are, it’s still got to be reading in psi…. Even if it is not a precise reading..

Right ?

 

[YukonLover]

Wait a minute.. So then what is it calibrated to? Even if the dummy gauge as i call them are not entirely accurate.. which i never truly believe they are, it’s still got to be reading in psi…. Even if it is not a precise reading..

Right ?

It reads like I solve calculus... and I can't do that. lol

 

[strutaeng]

Wait a minute.. So then what is it calibrated to? Even if the dummy gauge as i call them are not entirely accurate.. which i never truly believe they are, it’s still got to be reading in psi…. Even if it is not a precise reading..

Right ?

Umm. IDK if anyone has actually done a direct comparison of cluster gauge vs mechanical guage. Maybe with a tee/plumbing and both sender a mechanical guage hooked up at the same time?

To me it's more like "low, medium, and high" readings. I believe Fords of this generation show this on the cluster. I think most cars don't even show an oil pressure gauge, no?

 

[PPV_2018]

Umm. IDK if anyone has actually done a direct comparison of cluster gauge vs mechanical guage. Maybe with a tee/plumbing and both sender a mechanical guage hooked up at the same time?

To me it's more like "low, medium, and high" readings. I believe Fords of this generation show this on the cluster. I think most cars don't even show an oil pressure gauge, no?

Well that’s actually kind of the way i look at it but instead of low/normal/high more like “here’s a ballpark range of the pressure”

Again i never believe the dummy gauges are particularly accurate, but still feel like some sort of system/sensor is measuring psi and pushing the needle around more or less psi.

I am not saying you are wrong, you could be totally correct but also with your theory I think like there would be less inconsistencies in the readings if it was basically reading at low/normal/high. Ie: the gauges would basically only read at 20/40/60 psi (save 0 and 80 psi for equipment failures). But if your gauge is reading 30-35 psi in the city, then 40 on highway, then 25 idling at a red light , just seems like these readings (even if not particularly accurate) are coming from something giving more precise readings than just low/med/high.. but honestly i really don’t know, so. . . Just saying for the sake of discussion.

As far as other vehicles, i really have no idea. Practically every vehicle I’ve ever owned or driven has been a large Chevrolet or Ford SUV or pickup truck with a V8 that definitely *did* have an oil pressure gauge, and the few exceptions I don’t particularly remember. I don’t doubt that most passenger sedans and coupes/crossovers may not even have an OP dummy gauge on the dash, especially newer vehicles.

 

[Donal]

Hi everyone,

I know oil pressure seems like a common question. But, what I don't understand is the constant variations; especially when there is void of any precursor. I have a 2003 4x4 with a 5.3. I replaced the pump, timing equipment, and pick up tube, gaskets ect. And it ran 35-40 PSI cold or hot idle, and around 45-55 under load. This truck had around 224k.

I have another 2001 2 wheel drive, and when I got it, it idled around 30 PSI cold, and 25-30 hot, and under load 39 PSI. I have been delivering for a company packages 3x a week for several weeks, the truck has been running 8-12 hour days, 80 miles a day and idling with limited start and stops. The oil, when cooled and dropped to the pan is a bit tacky, but not dirty. I maybe burned off at most half a quart since I changed the oil about 1500-1800 miles ago. Just last night my oil PSI seemed to be warm fighting 20-25 PSI sometimes not going past 20-22 PSI, and under load various pressures between 32-39 PSI approximately. Noticing a drop here.

I am getting ready to change the oil, and I did some research and shows that Royal Purple HPS has the most zinc at 1275, most oils are more more than 950. Apparently RP is not API standard, so they can add whatever they want, and their film strength is also superior, as I have seen in several test videos. Im looking for a bit more zinc and some extra film strength to keep it going longer. I was hoping to increase some pressure by having a thicker oil. I was thinking of adding some lucas to my current oil brand. But then I seen the natural lucas thickness, and I said what if I just use that and increased to 5w40 instead of 5w30? I heard a lot of people allege lucas made their bearing tolerances worse, so it improved temporarily, but just made the inevitable happen with just straight weight oil. I ahve been using Valvoline MAXlife high mileage for over a decade, but I feel in this engine maybe its not appropriate.

My plan was to use RP 5w40 and a good quality filter, possible replace the oil sending unit. And then say in 1,000 miles run some marvel mystery through it for another 500 miles, and then do a complete straight RP 5w40 swap until I have to change the pump out. Sound like a good idea?

Maybe you can check the operating oil level when the engine is warm and on level ground. Engine at normal idle speed.

 

[Joseph Garcia]

Interesting. As part of an ongoing major mod, I just had my oil pressure measured with a mechanical oil pressure gauge to test the accuracy of my cluster oil pressure gauge, and both gauges were within a few PSI of each other, both at idle and and at 2500 RPM.

 

[strutaeng]

Interesting. As part of an ongoing major mod, I just had my oil pressure measured with a mechanical oil pressure gauge to test the accuracy of my cluster oil pressure gauge, and both gauges were within a few PSI of each other, both at idle and and at 2500 RPM.

That's good to know. Maybe I'm completely wrong and just don't know it then? This is on a GMT900, right? I believe in those vehicles the oil pressure is actually shown on a PID, no? Maybe something changed?

The GMT800s don't show oil pressure on PID, as far as I know.

Thanks for sharing your findings.

 

[Joseph Garcia]

That's good to know. Maybe I'm completely wrong and just don't know it then? This is on a GMT900, right? I believe in those vehicles the oil pressure is actually shown on a PID, no? Maybe something changed?

The GMT800s don't show oil pressure on PID, as far as I know.

Thanks for sharing your findings.

Yes, it is a GMT900 truck.

 

[rockola1971]

Umm. IDK if anyone has actually done a direct comparison of cluster gauge vs mechanical guage. Maybe with a tee/plumbing and both sender a mechanical guage hooked up at the same time?

To me it's more like "low, medium, and high" readings. I believe Fords of this generation show this on the cluster. I think most cars don't even show an oil pressure gauge, no?

Why do believe the mechanical gauge is "more or less" accurate than the sender type? They both have a percentage of error. Doubt GM lists the accuracy range. I would hazard to guess that its a +10/-10% error range which is only +/- 3psi at 30 PSI. While not truly significant error at just 3psi range, it is still an error. The problem with the sender type is the error stacking. You have the sender, wiring connection, Cluster wiring, board connections and traces with the silver migration problems and then ultimately the DC stepper motor for the gauge needle itself. All of those can add to the overall error. Sure the whole system is accurate enough when the vehicle rolls off the line with that new car smell but thing degrade over time and our generation chassis aint getting any younger. Take for instance a wore out front suspension which creates havoc alone on the electrical system with all the jolts every time a decent rough spot in the road or offroad is encountered.

 

[nonickatall]

At first, my truck's oil pressure was relatively low.

I started by replacing the O-ring on the oil pump. That helped a little.

But what helped the most was that for the last four oil changes I have added 1 liter of diesel to the oil before each oil change and driven 20 to 30 km with it.

That loosens the carbon in the engine. I don't know why that increased the oil pressure. According to my technical understanding, it should actually reduce it, because the back pressure in the system is reduced. Maybe it loosened the carbon from the pressure relief valve.

I have no idea.

But my oil pressure is much better. And the ticking noise of my hydross is almost gone.

Of course it is lower when the car is in idle, than when it is driving, and of course it is lower when the oil is very hot, than when it is cold.

But it is never too low since.

 

[Marky Dissod]

Why do you believe the mechanical gauge is "more or less" accurate than the sender type?
They both have a percentage of error. Doubt GM lists the accuracy range.
I would hazard to guess that its a +10/-10% error range which is only +/- 3psi at 30 PSI.
While not truly significant error at just 3psi range, it is still an error. The problem with the sender type is the error stacking.
You have the sender, wiring connection, cluster wiring, board connections and traces with the silver migration problems,
and then ultimately the DC stepper motor for the gauge needle itself.

All of those can add to the overall error.
Sure the whole system is accurate enough when the vehicle rolls off the line with that new car smell,
but things degrade over time and our generation chassis ain't getting any younger.

... my '02 Tahoe now idles at operating temp @ 360RpM ...
... at least according to my tachometer's needle, which has clearly escaped its original tolerances.

I know my engine ACTUALLY idles at 600RpM, because I checked.