HPL PCMO 15w-40, 120 mi Baseline; 2011 Lexus GX460, 1UR-FE 4.6L V8, 170k miles

[Hohn]

Following the prescibed method here, I’m starting my HPL history for real on my well-used GX460. The GX is coming off an 8k run of HPL PCMO in 5w30. I did not analyze that first drain. With this, I’m on a nice even 10k mile increment (170k) with my preferred oil for this vehicle, and of course, with 120 miles on this sample, this is as boring as oil samples get.

Still, it may perhaps be of interest to compare the HPL PCMO oil in 40 grade to lighter grades that might be getting the a slightly different add packs.

I’m seeing a modest Ester kick (oxidation of 23), some healthy phosphorus levels that are bang on the 800ppm limit for API SP, decent but modest calcium in keeping with more recent, lower-calcium add packs, and yet we still get a reasonable slug of Moly.

I think this is a reasonably clean sample as a useful base. I assume the silicon is supposed to be there as part of the anti-foam. The trace iron and aluminum I’d consider to be noise.

I’ll post the 5k follow up when it comes. I’m really curious to see how the 15w40 compares to 5w and 0w 40 grades or even 30 grades in PCMO in terms of general wear performance.


Apologies if this doesn’t belong in “used” oil analysis, but it’s not really a VOA since it came from the engine and not the bottle, so.

 

[folzag2]

Why did you decide to go with 15W instead of 5W or 10W, especially in Indiana? Seems like modern oils don't give up anything stretching to the lower winter ratings, and HPL base oil ought to give up even less than that.

 

[Hohn]

Why did you decide to go with 15W instead of 5W or 10W, especially in Indiana? Seems like modern oils don't give up anything stretching to the lower winter ratings, and HPL base oil ought to give up even less than that.

I've sort of addressed that in a roundabout fashion elsewhere, but it's a reasonable question and this is probably a good place to consolidate that rationale.

Here, in no particular order is why I chose this product from HPL:

• It's a unique product. The list of non-diesel, gasoline-only add pack 15w40 oils is to my knowledge, just one deep. Sort of like HPL's 10w20 grades-- nobody else is doing this.
• The 15w allows either an entirely different base oil to be used, or to use a blend that includes a thicker base oil. Why do we want a thicker base oil?
  • Thicker base oils have higher density. This raises dynamic viscosity for the same Kinematic Viscosity. In the HPL line, only the straight SAE 40 PCMO has a higher density as a 40 grade.
  • Thicker base oils can have lower volatility and/or oxidation rates. For example, in AN bases, synesstic 5 has a flashpoint of 222C but synesstic 12 is up at 258C. In PAO world, SpectraSyn 4 has a flashpoint of 220C. But SpectraSyn 10 has a flashpoint of 266C. In the HPL line, the 15w40 PCMO has the second highest flashpoint of any 40 grade. Only the SAE 40 is higher within 40 grades, and the PCMO 40 grades are higher than all the other lines 50 grades. If you value a higher flashpoint like I do, then the 15w40 is a great way to maximize that without losing acceptable winter performance.
  • Thicker base oils allow little to no VII improver, improved many of the properties listed-- density, volatility, temporary shear viscosity, etc.
• The cold weather performance loss of a 15w is smaller than one might think, depending on how you define "cold." Keep in mind that differences in "w" ratings roughly correspond to difference in degrees Celsius temperature. In other words, the cold weather performance of a 15w is roughly 10°C worse than a 5w. That's a difference of 18°F. That's not a whole lot in real world winter driving.
  • The pour point is a relevant spec because it indicates the temperature at which the oil will flow (under gravity). This is also how well oil will flow back to the pan and prevent the oil pickup tube from sucking a hole in a solid block of oil goo. It therefore represents the absolute lower limit of cold performance. You'll note the almost every HPL PCMO grade has a similar pour point. So it's helpful to think of HPL PCMO cold weather performance in terms of the slope of the curve of how viscosity drops as you rise above -40 temp. All the PCMOs are not good below -40. And they start becoming OK at different rates as you warm from there. The "w" ratings are essentially just the respective Y intercept points of those curves.
  • The 15w40 has essentially the same cranking viscosity at -25C as the 5w20 does at -35C. While both temperatures are exceedingly unlikely in Indiana, I've successfully started engines on several occasions with 5w oils at -35C (or lower!). If I find that performance acceptable, why would I not find acceptable a 15w at -25c
• Going 15w in HPL is NOT the same as using a 15w from the wal-mart aisle. While those other oils use the tight spread of 15w-40 to use the cheapest bases possible, that's not true of HPL. In other words, the tight spread in HPL truly is the chance for a performance increase rather than a cost decrease.
• DUTY CYCLE: my vehicles see a lot of short tripping and errand running. You can drive across town for us in 15 minutes, so most trips are less than that. IN my wife's usage, it's common to have 5-6 individual starts averaging less than 15 minutes. IN applications like this, it's often useful to think not in terms of "how fast can I get oil pressure?" and instead think in terms of "how slowly will my oil drain back?". IN start/stop usage with lots of short trips, I think thicker oils are preferable. I don't have many cold starts, but there are LOTS of warm starts.
  • Incidentally, this usage is often associate with fuel dilution from prolonged warmish (but not hot) temperatures. A thicker oil is more tolerant to dilution.
  • The typical start is from a relatively warm garage.
  • My vehicles all warm pretty quickly. Hondas are known for this, but my GX460 also warms surprisingly quickly for a 4.6L V8.

So there you have it: in the HPL line, the tight number spread can offer an actual performance increase in terms of oxidation resistance, temporary shear viscosity, and volatility while still having acceptable viscosity within all relevant temperature ranges.

 

[53' Stude]

I've sort of addressed that in a roundabout fashion elsewhere, but it's a reasonable question and this is probably a good place to consolidate that rationale.

Here, in no particular order is why I chose this product from HPL:

• It's a unique product. The list of non-diesel, gasoline-only add pack 15w40 oils is to my knowledge, just one deep. Sort of like HPL's 10w20 grades-- nobody else is doing this.
• The 15w allows either an entirely different base oil to be used, or to use a blend that includes a thicker base oil. Why do we want a thicker base oil?
  • Thicker base oils have higher density. This raises dynamic viscosity for the same Kinematic Viscosity. In the HPL line, only the straight SAE 40 PCMO has a higher density as a 40 grade.
  • Thicker base oils can have lower volatility and/or oxidation rates. For example, in AN bases, synesstic 5 has a flashpoint of 222C but synesstic 12 is up at 258C. In PAO world, SpectraSyn 4 has a flashpoint of 220C. But SpectraSyn 10 has a flashpoint of 266C. In the HPL line, the 15w40 PCMO has the second highest flashpoint of any 40 grade. Only the SAE 40 is higher within 40 grades, and the PCMO 40 grades are higher than all the other lines 50 grades. If you value a higher flashpoint like I do, then the 15w40 is a great way to maximize that without losing acceptable winter performance.
  • Thicker base oils allow little to no VII improver, improved many of the properties listed-- density, volatility, temporary shear viscosity, etc.
• The cold weather performance loss of a 15w is smaller than one might think, depending on how you define "cold." Keep in mind that differences in "w" ratings roughly correspond to difference in degrees Celsius temperature. In other words, the cold weather performance of a 15w is roughly 10°C worse than a 5w. That's a difference of 18°F. That's not a whole lot in real world winter driving.
  • The pour point is a relevant spec because it indicates the temperature at which the oil will flow (under gravity). This is also how well oil will flow back to the pan and prevent the oil pickup tube from sucking a hole in a solid block of oil goo. It therefore represents the absolute lower limit of cold performance. You'll note the almost every HPL PCMO grade has a similar pour point. So it's helpful to think of HPL PCMO cold weather performance in terms of the slope of the curve of how viscosity drops as you rise above -40 temp. All the PCMOs are not good below -40. And they start becoming OK at different rates as you warm from there. The "w" ratings are essentially just the respective Y intercept points of those curves.
  • The 15w40 has essentially the same cranking viscosity at -25C as the 5w20 does at -35C. While both temperatures are exceedingly unlikely in Indiana, I've successfully started engines on several occasions with 5w oils at -35C (or lower!). If I find that performance acceptable, why would I not find acceptable a 15w at -25c
• Going 15w in HPL is NOT the same as using a 15w from the wal-mart aisle. While those other oils use the tight spread of 15w-40 to use the cheapest bases possible, that's not true of HPL. In other words, the tight spread in HPL truly is the chance for a performance increase rather than a cost decrease.
• DUTY CYCLE: my vehicles see a lot of short tripping and errand running. You can drive across town for us in 15 minutes, so most trips are less than that. IN my wife's usage, it's common to have 5-6 individual starts averaging less than 15 minutes. IN applications like this, it's often useful to think not in terms of "how fast can I get oil pressure?" and instead think in terms of "how slowly will my oil drain back?". IN start/stop usage with lots of short trips, I think thicker oils are preferable. I don't have many cold starts, but there are LOTS of warm starts.
  • Incidentally, this usage is often associate with fuel dilution from prolonged warmish (but not hot) temperatures. A thicker oil is more tolerant to dilution.
  • The typical start is from a relatively warm garage.
  • My vehicles all warm pretty quickly. Hondas are known for this, but my GX460 also warms surprisingly quickly for a 4.6L V8.

So there you have it: in the HPL line, the tight number spread can offer an actual performance increase in terms of oxidation resistance, temporary shear viscosity, and volatility while still having acceptable viscosity within all relevant temperature ranges.

I may consider this for my Dakota. It’s parked outside all the time.
I’m not having any issues with HPL 5w30 CK4 HDEO so far

 

[Hohn]

I may consider this for my Dakota. It’s parked outside all the time.
I’m not having any issues with HPL 5w30 CK4 HDEO so far

Nor would I expect any. What benefits were you seeking using the ck4 HDEO vs their PCMO?

 

[53' Stude]

Nor would I expect any. What benefits were you seeking using the ck4 HDEO vs their PCMO?

Easier startup in winter and see if it cleaned better than a PCMO. I’m pleased so far.

 

[folzag2]

So there you have it: in the HPL line, the tight number spread can offer an actual performance increase in terms of oxidation resistance, temporary shear viscosity, and volatility while still having acceptable viscosity within all relevant temperature ranges.

Interesting. Thanks for the thorough reply.

You also hit on something that's always bothered me. Here in Portland, OR, I don't need a 5W, and certainly don't need a 0W. But the base oils in the 10W's and 15W's aren't as trustworthy as in the 0 & 5 W's so I end up going with them with more VII's than I really want because they have the base oil I want. But, yeah, what I really want for all but about 10 days a year is a 15W, but with the high quality of base oil's that are in the 0W's.

What's more, of those 10 days, 5 of them would work with a 10W, and the other 5, heck, I'd just leave it parked.