Pressure drop when using pennzoil full synthetic

[Gokhan]

Originally Posted by ZeeOSix
M1 full synthetic is HTHS of 3.1 per their latest spec sheet. I can't see a 0.1 or 0.2 difference in HTHS making the oil pressure get cut in half.at idle. Here's some data that shows the oil pressure isn't that sensitive to HTHS ... at least not as sensitive as the OP numbers seem to be. Could be each engine has it's own HTHS vs OP "curve slope", but I just can't see the line slope being as drastic as the numbers the OP has given.

Originally Posted by OVERKILL
In my experience with an SBF, going from a 0w-20 to a 0w-40 had less than a 10psi impact on oil pressure hot at idle (not an SBC I know). So I have a hard time with two oils that are maybe .1 off from each other in HTHS and with nary identical KV100's showing that much of a difference.

In a healthy engine, yes, the oil pressure should be more or less proportional to the HTHSV so that you would see about a 7% difference when going from 3.0 to 3.2 cP.

However, if the bearing clearances have increased a lot due to wear, there would be a critical viscosity where the side leakage from the bearings is large enough so that you don't have enough oil going further up the engine to maintain the oil pressure when the viscosity falls below this critical value. It could be that this critical viscosity is right around 3.2 cP now and it may get higher in the future.

This is some simple but nice explanation of causes of low oil pressure:

https://www.chicagotribune.com/news/ct-xpm-2001-01-15-0101150132-story.html

 

[Gokhan]

Originally Posted by Tyler13
I have been concerned and curious about this for probably about a couple years now. Thanks for explaining how same viscocity oil can have such variance in pressure. At this point I will stick with the Valvoline and as long as the pressure remains on the higher side between change cycles, as it has with Valvoline, will just "go with the flow". Until there is degradation using the Valvoline, which I have not seen up to now, I will live with it as is.

Thanks to those who read and responded seriously. You have allayed any serious concerns, will switch back to the Valvoline as planned, and prepare to enjoy Easter weekend up on Cape Breton Island. I will also look for a local source for the Kendall Euro.

Thank you

You're welcome.

Yes, since your problem seems to be cured by going to a slightly higher viscosity, I would definitely go with a Euro 5W-30, 0W-40, or 5W-40 with ACEA C3 or A3/B4 specs or even a 5W-30 or 5W-40 HDEO with API CK-4/SN specs. They would have HTHSV in the range 3.5 - 4.5 cP, depending on the viscosity and brand. This would give you a much safer margin of viscosity than the 0.2 cP between PPPP 5W-30 and VAS 5W-30.

I would also do a used-oil analysis (UOA) to see how much bearing materials (usually lead and copper) show up. You might not have much lead overlay left though. Avoiding extended UOAs will also decrease the lead and copper wear by reducing the corrosion of these elements.

 

[ARCOgraphite]

Tyler - So you dont waste that pennzoil, just drain a quart and replace with a qt of PP Euro 5w40. and see what happens.

A Bit of trouble but for less than 10 bucks youll get a good data point and an oil sump viscosity near where your Valvoline would be.

 

[Gokhan]

Originally Posted by ARCOgraphite
Tyler - So you dont waste that pennzoil, just drain a quart and replace with a qt of PP Euro 5w40. and see what happens.

A Bit of trouble but for less than 10 bucks youll get a good data point and an oil sump viscosity near where your Valvoline would be.

He seems to need HTHSV > 3.2 cP. PPPP 5W-30 has 3.0 cP. If PPPPE 5W-40 has 3.7 cP, he would need 2 - 3 qt of it depending on his oil-sump capacity.

An HDEO like Delo XSP 5W-40 has 4.2 cP. 1 qt of it could be sufficient to boost his HTHSV.

 

[ARCOgraphite]

But A little VM goes a long way.

Hows that 0W20 M1 EP treating you? Chicken Kung PAO?!
Id like to run it on a stick car but don't have an application.

 

[Gokhan]

Originally Posted by ARCOgraphite
Hows that 0W20 M1 EP treating you? Chicken Kung PAO?!
Id like to run it on a stick car but don't have an application.

The PAO-based M1 EP 0W-20 SN PLUS has been fabulous! I don't remember my engine running anywhere as smooth! I feel like my car is soaked in butter when I drive. Seriously, it has made a huge difference in the smoothness of my engine. It probably has picked up a few percent in hp and mpg. It's probably a combination of the PAO/POE and Infineum OFM.

 

[ARCOgraphite]

I don't know if you are kidding or not, but, if you are NOT then - sounds good to me! I keep mentioning the the "real" synthetics have noticeably better performance from the phony group III blends at Extreme cold starts and ring land cleanliness - thus equal cyl balance and smoothness. OR its just a figment.

Wonder what the diff between VW 508 spec and M1 EP or AP .... I feel odd being out of the oil loop being at the mercy of the VW dealer during my lease and ANNUAL (gasp!) OCI

 

[dave1251]

Originally Posted by ARCOgraphite
I don't know if you are kidding or not, but, if you are NOT then - sounds good to me! I keep mentioning the the "real" synthetics have noticeably better performance from the phony group III blends at Extreme cold starts and ring land cleanliness - thus equal cyl balance and smoothness. OR its just a figment.

Wonder what the diff between VW 508 spec and M1 EP or AP .... I feel odd being out of the oil loop being at the mercy of the VW dealer during my lease and ANNUAL (gasp!) OCI

What do you consider "fake" synthetic. Group III's are not created equal.

 

[Gokhan]

Originally Posted by ARCOgraphite
I don't know if you are kidding or not, but, if you are NOT then - sounds good to me! I keep mentioning the the "real" synthetics have noticeably better performance from the phony group III blends at Extreme cold starts and ring land cleanliness - thus equal cyl balance and smoothness. OR its just a figment.

No kidding. I'm 100% serious. I don't kid about the motor oil in my sump.

Originally Posted by ARCOgraphite
Wonder what the diff between VW 508 spec and M1 EP or AP .... I feel odd being out of the oil loop being at the mercy of the VW dealer during my lease and ANNUAL (gasp!) OCI

According to the MSDS, Castrol LL IV 0W-20 VW 508.00 is half-PAO-based, similar to M1 AFE 0W-20 in that respect.

These European OEM 0W-20 oils are based on ACEA C5. One thing I noticed about them is that, according to the (1 - A_Harman index)/2, which gives a rough estimate of the VII treat rate, they have very little VII, with the VII treat rate at or below 1%. M1 EP has a VII treat rate about three times as large. So, this is a good thing about these European OEM 0W-20 oils.

Also, M1 AFE 0W-20 and M1 EP 0W-20 have 650 ppm phosphorus, which is below the 700 - 900 ppm ACEA C5 range, which would disqualify them from certifiable for it, even though it probably doesn't make much difference in terms of wear if at all.

So, the main disadvantage of Castrol LL IV 0W-20 is that it has only about half the PAO of M1 EP 0W-20. VIIs do increase the turbo deposits but M1 EP 0W-20 is still low in them and it probably uses the low-deposit type OCP VII anyway. So, you would be OK using it out of the warranty period, assuming it still stays PAO. You may get better results with it than with the Castrol LL IV 0W-20 and save a lot of money as well.

 

[OilUzer]

Originally Posted by ZeeOSix
Originally Posted by MrMoody
Originally Posted by ZeeOSix
A positive displacement oil pump is going to force the same oil flow volume through any filter at idle.

Even if this was true, much less on a worn pump, the pressure is measured after the filter, and different filters can have different delta-p at the same flow and viscosity. Not that it should be much on a new filter with hot oil.


You missed the point. With a positive displacement oil pump (assume it's healthy) the same flow will be at the pressure sensor (especially at idle RPM) regardless of the filter's flow restriction. The only thing that happens with a more flow restrictive filter is the delta-p across the filter increases with the same flow. If the flow is the same coming out the filter at the point of the pressure sensor (ie, because of the positive displacement oil pump), then there will be no loss in measured oil pressure because of oil filter restriction.


I was looking for this info some where else and ran into it in this thread ... Anyways was going to to mark it with a "." but decided to ask this question instead.

Most cars that I have seen with oil pressure gauge don't have any specific marking for what the psi should be. Mine has a dummy gauge with no marking at all. No numbers, no high or low, no color (e.g. Red zone, etc.) ... and it usually sits somewhere in the middle +/- so if I change the oil and it's a little higher or lower, I wouldn't know if it's good or bad. Wondering if op is over thinking this?

 

[Merek]

I'd like to know how many miles are on the truck and the oil filter that was used from both oil change places. I have a 2004 Sierra w/ 5.3 110k and I use PP 5w30 and have for the last several changes and no issues with oil pressure, I use the regular and not the HM.

The only sure fire way to know what was used is to either watch them pour it in or to change it yourself which is why I change my own oil, the OP could have samples tested and see what the results are. I'm wondering if the Pennzoil that was used could possibly be a 5w20 whereas Valvoline is using 5w30.

You have to really be careful at these oil change places and even the dealerships sometimes with them using the correct oil for your vehicle. I know with my Civic that Honda states you can use 5w20 back to 2000, mine is a '99 and honestly there wasn't any real changes at least not internally from 96-00, I think they only went as far back to 2000 for the age of the vehicle but being so close someone could mistakenly use 5w20 instead which I did once just to use up a jug of oil I had sitting around and didn't experience any issues, it was Castrol Edge Titanium in the gold bottle, a great oil but not cheap by any means. I do not have an oil pressure gauge hooked up but I didn't notice anything different while it was in there, no noises or knocking.

 

[Merek]

Originally Posted by OilUzer
Originally Posted by ZeeOSix
Originally Posted by MrMoody
Originally Posted by ZeeOSix
A positive displacement oil pump is going to force the same oil flow volume through any filter at idle.

Even if this was true, much less on a worn pump, the pressure is measured after the filter, and different filters can have different delta-p at the same flow and viscosity. Not that it should be much on a new filter with hot oil.


You missed the point. With a positive displacement oil pump (assume it's healthy) the same flow will be at the pressure sensor (especially at idle RPM) regardless of the filter's flow restriction. The only thing that happens with a more flow restrictive filter is the delta-p across the filter increases with the same flow. If the flow is the same coming out the filter at the point of the pressure sensor (ie, because of the positive displacement oil pump), then there will be no loss in measured oil pressure because of oil filter restriction.


I was looking for this info some where else and ran into it in this thread ... Anyways was going to to mark it with a "." but decided to ask this question instead.

Most cars that I have seen with oil pressure gauge don't have any specific marking for what the psi should be. Mine has a dummy gauge with no marking at all. No numbers, no high or low, no color (e.g. Red zone, etc.) ... and it usually sits somewhere in the middle +/- so if I change the oil and it's a little higher or lower, I wouldn't know if it's good or bad. Wondering if op is over thinking this?




The oil pressure gauge does have markings and you can figure it out by calculating how much each line or increment is worth, the gauge reads 0-40-80 with lines in between. It's not some oil pressure gauge used on old tractors that only list low-high or Ford's that just say "Normal", a quick google search of 2004 GMC Sierra gauges will show you how it is, his truck is a 2003 and a Chevrolet but is exactly the same as mine.

 

[ZeeOSix]

Originally Posted by Merek
Originally Posted by OilUzer
I was looking for this info some where else and ran into it in this thread ... Anyways was going to to mark it with a "." but decided to ask this question instead.

Most cars that I have seen with oil pressure gauge don't have any specific marking for what the psi should be. Mine has a dummy gauge with no marking at all. No numbers, no high or low, no color (e.g. Red zone, etc.) ... and it usually sits somewhere in the middle +/- so if I change the oil and it's a little higher or lower, I wouldn't know if it's good or bad. Wondering if op is over thinking this?

The oil pressure gauge does have markings and you can figure it out by calculating how much each line or increment is worth, the gauge reads 0-40-80 with lines in between. It's not some oil pressure gauge used on old tractors that only list low-high or Ford's that just say "Normal", a quick google search of 2004 GMC Sierra gauges will show you how it is, his truck is a 2003 and a Chevrolet but is exactly the same as mine.


Some of those archaic oil pressure gauges are not very linear. You would have to put a mechanical oil pressure gauge on the engine and essentially check the "calibration" of the dash gauge against a good know accurate pressure gauge.

 

[Merek]

Originally Posted by ZeeOSix
Originally Posted by Merek
Originally Posted by OilUzer
I was looking for this info some where else and ran into it in this thread ... Anyways was going to to mark it with a "." but decided to ask this question instead.

Most cars that I have seen with oil pressure gauge don't have any specific marking for what the psi should be. Mine has a dummy gauge with no marking at all. No numbers, no high or low, no color (e.g. Red zone, etc.) ... and it usually sits somewhere in the middle +/- so if I change the oil and it's a little higher or lower, I wouldn't know if it's good or bad. Wondering if op is over thinking this?

The oil pressure gauge does have markings and you can figure it out by calculating how much each line or increment is worth, the gauge reads 0-40-80 with lines in between. It's not some oil pressure gauge used on old tractors that only list low-high or Ford's that just say "Normal", a quick google search of 2004 GMC Sierra gauges will show you how it is, his truck is a 2003 and a Chevrolet but is exactly the same as mine.


Some of those archaic oil pressure gauges are not very linear. You would have to put a mechanical oil pressure gauge on the engine and essentially check the "calibration" of the dash gauge against a good know accurate pressure gauge.


Agreed, also these trucks have the stepper motors that can go bad in the gauge cluster, my speedometer stopped working a long time ago and found a place online that replaced all of those motors, under warranty or if you have the dealer repair it they will only replace the one(s) that are defective... However the odd thing is when he uses Pennzoil the gauge reads low and Valvoline is normal which leads me to believe different Oil Viscosity's were used or something is up with the oil filter.

 

[ZeeOSix]

Originally Posted by Merek
However the odd thing is when he uses Pennzoil the gauge reads low and Valvoline is normal which leads me to believe different Oil Viscosity's were used or something is up with the oil filter.


Last thing I'd suspect is the oil filter as explained earlier. A positive displacement oil pump will ensure the flow is kept the same as long as the pump isn't in pressure relief, which it will not be at lower RPM with hot oil, unless the pump's pressure relief valve is malfunctioning (ie, stuck cracked open).

 

[Garak]

Originally Posted by ZeeOSix
Some of those archaic oil pressure gauges are not very linear. You would have to put a mechanical oil pressure gauge on the engine and essentially check the "calibration" of the dash gauge against a good know accurate pressure gauge.

Heck, even when an OEM (GM comes to mind) used a properly functioning oil pressure gauge, there were complaints because people didn't realize that oil pressure varies by temperature and RPM.

 

[ZeeOSix]

Originally Posted by Garak
Originally Posted by ZeeOSix
Some of those archaic oil pressure gauges are not very linear. You would have to put a mechanical oil pressure gauge on the engine and essentially check the "calibration" of the dash gauge against a good know accurate pressure gauge.

Heck, even when an OEM (GM comes to mind) used a properly functioning oil pressure gauge, there were complaints because people didn't realize that oil pressure varies by temperature and RPM.


LoL ... yeah, when I see or read that someone doesn't know that oil pressure in a PD oil pump system changes with oil temp and engine RPM I just go ...

 

[Garak]

I preferred when GM had it right. In the taxis and so forth, you could have an idea of what the oil pressure was actually doing. Damped gauges and gauges that are actually idiot lights in disguise do not impress me.

 

[Propflux01]

What about the 'lifter' noise he described in the OP?

 

[ARCOgraphite]

Originally Posted by dave1251
Originally Posted by ARCOgraphite
I don't know if you are kidding or not, but, if you are NOT then - sounds good to me! I keep mentioning the the "real" synthetics have noticeably better performance from the phony group III blends at Extreme cold starts and ring land cleanliness - thus equal cyl balance and smoothness. OR its just a figment.

Wonder what the diff between VW 508 spec and M1 EP or AP .... I feel odd being out of the oil loop being at the mercy of the VW dealer during my lease and ANNUAL (gasp!) OCI

What do you consider "fake" synthetic. Group III's are not created equal.

I suppose GTL doesnt belong in group III but its a paraffin as are other III's It's NOT an PAO or POE that many are familiar with when purchasing true synthetic oils decades ago. And they do not have even close to the same perceived performance IMHO.