Please post your UOA here to compare.

I'm genuinely curious. Why did you obtain this? It's in the neighborhood of the price of 2 quarts of oil. How will it help you save money and/or fuel?

 

First thing I noticed on this report is that it lists the engine as 1.5L; the 2010 should be 1.8L engine! Perhaps the testing agency made a mistake?

 

Your question was about 5W-20 vs. 0W-20. My practice is to send a reference sample to the lab and get a 40C and 100C viscosity test. The ratio of viscosities gives a true measure to confirm the oil type. Since the 20W refers to the 100C viscosity, I would expect a 40C viscosity or a 'pour' test to determine if the oil is 5W or 0W.

I use a different lab because they analyze the oil including the 40C/100C viscosity test for $20:

R&G Laboratories, Inc.
217 Hobbs Street, Suite 105
Tampa, FL 33619
​

I have no interest in R&G except as a repeat customer.

I've been more interested in transaxle lubrication because all power has to pass through enroute to the wheels. I've uploaded the transaxle oil samples here. This is an overflow area for "Prius Technincal Stuff."

It is interesting to compare and contrast the differences between this ICE and my ZVW30, 5k mile, transaxle oil sample:

• Molybdenum, Zinc - the ICE oil is loaded but the transaxle is free. Molybdenum is a dry lubricant often used to assemble engines and zinc helps with high pressure lubrication. I suspect there is a materials issue with molybdenum that precludes its use in the transaxle ... possibly the magnets? Perhaps the stator potting compound? This is not an experiment I look forward to testing. But the transaxle should be free of the cylinder ring stress that zinc would help.
• Calcium - the ICE oil has 20 times the amount in the transaxle.
• Phosphorous - the ICE has 3 times the transaxle oil level.
• Silicon - probably leaching from the sealant, just as in the transaxle.

Near as I can tell, the straight line approximation suggests the initial transaxle oil is good for ~15,000 miles. Certainly I'll wait until reaching 20k miles before the second change. However, the microscopic examination and particle loads from R&D Labs suggests an early change may be warranted:

The "red oxide" is often used to color silicon sealants so I don't have much concern about it. What I was more concerned about were wear particles and my initial change probably flushed must out.

Bob Wilson

 

Wow Bob, they really took a close look at the particles. How is this done?

 

A little pricy, I asked for a microscopic analysis.

Bob Wilson

 

The general recommendation is:

• NHW20 - 60k miles based upon the samples tested
• NHW11 - 30k miles based upon the samples tested

The ZVW30 is new and I don't think anyone has tried a series of transaxle oil tests from the beginning. My hope is the 20k mile test (5k + 15K) will come in with less than a 5% loss in viscosity and low Si. This would suggest at least a 45k or larger change interval after the first one.

I was pretty impressed by the cold-weather, roll-down test of my NHW11 after the first transaxle change. But it takes someone willing to investigate ... to measure ... before we have trustable data.

Bob Wilson

 

are you guys buying the kits online or from auto parts store? can't remember ever seeing an oil analysis kit and amazon only has a couple types.

 

What does the acronym UOA mean? University of Arizona? Universal Outdoor Adventure?

 

they run fast and loose with the acronyms here My guess is Used Oil Analysis

 

I thought it was User Oil Analysis but used makes more sense.

Bob Wilson

 

I get the small water bottles and after draining and drying, use them to hold the sample. Collect half a cup or more; put the lid on tight; double bag; and off it goes.

Bob Wilson

 

3rd Oil Change

Blackstone Labs
Equipment Make & Model: 2008 Toyota Prius
OIL TYPE & GRADE: Mobil 1 5w30
Mobil 1 filter
Make-up oil: 0
OIL USE INTERVAL: 10,000
Miles on unit: 37,000
Sample Date: 11/10/2009

We found no significant change in the latest sample from your Prius. The 10,000 mile oil changes are
working well for you but we think you could easily be going longer on your oil. Try ~12,000 miles next time
and check back for another look at wear. Silicon improved a little here and should continue to do so with
each oil change. The trace of fuel that we found isn't an issue and no other harmful contaminants showed
up. You still had plenty of active with a TBN reading of 3.5. We consider a reading of around 1.0 too low for
extended use. All in all, a good report.




ALUMINUM -4
CHROMIUM -0
IRON -14
COPPER -2
LEAD-0
TIN-2
MOLYBDENUM-84
NICKEL-0
MANGANESE-1
SILVER-0
TITANIUM-0
POTASSIUM-2
BORON-38
SILICON-23
SODIUM-5
CALCIUM-2333
MAGNESIUM-12
PHOSPHORUS-666
ZINC-809
BARIUM-0


cSt Viscosity @ 100°C 55.72
SUS Viscosity @ 210°F 8.99
Flashpoint in °F 365
Fuel % TR
Antifreeze % 0.0
Water % 0.0
Insolubles % 0.3
TBN 3.5
TAN
ISO Code

 

ATF Fluid

Blackstone Labs

31,365 miles on car and fluid
Factory Fill
No make up fluid





This being the first ATF sample since the transmission was new, the higher-than-average metals
and silicon are not surprising. Universal averages show typical wear levels for this type of transmission after
about 19,600 miles on the oil. The elevated metals readings are from new parts wearing-in, as well as
accumulated from normal use. Silicon is from sealers. The viscosity was a little light, likely from the long
ATF use. The TAN reading of 1.6 shows the ATF was somewhat acidic. Check back after 20K miles on the next oil.




ALUMINUM 46
CHROMIUM 3
IRON 103
COPPER 12
LEAD 1
TIN 3
MOLYBDENUM 1
NICKEL 6
MANGANESE 4
SILVER 0
TITANIUM 0
POTASSIUM 1
BORON 56
SILICON 184
SODIUM 3
CALCIUM 130
MAGNESIUM 3
PHOSPHORUS 282
ZINC 6
BARIUM 3





cSt Viscosity @ 100°C 42.7
SUS Viscosity @ 210°F 5.02
Flashpoint in °F 335
Fuel %
Antifreeze %
Water %
Insolubles % TR
TBN
TAN 1.6
ISO Code


I refilled with Redline D6, no noticeable change in performance.

 

2nd Oil Change

This second sample out of your Prius looks really good. The metals that were high last time have
improved here. They were just left over from the break-in period. You've kept this oil in place 10,000 miles
and wear is a little higher than average, but everything is properly balanced. You could try 12,000 miles next
oil change. The oil's TBN read 3.3, so there's still active additive remaining for a longer oil change. No fuel
found at all, compared to the 3.0% we found last time. No other contaminants found, either. This Prius is in
very good shape. No problems found.

Miles on oil 10,000
Miles on Unit 27,000
Sample Date 4/09/09
Make-up oil 0

Filter Purolator Pure One
Oil: Mobil 1 5w-30

ALUMINUM 5
CHROMIUM 0
IRON 14
COPPER 2
LEAD 0
TIN 1
MOLYBDENUM 41
NICKEL 0
MANGANESE 1
SILVER 0
TITANIUM 0
POTASSIUM 2
BORON 24
SILICON 27
SODIUM 6
CALCIUM 2863
MAGNESIUM 13
PHOSPHORUS 619
ZINC 732
BARIUM 0

SUS Viscosity @ 210°F 57.7
cSt Viscosity @ 100°C 9.55
Flashpoint in °F 370
Fuel % 0.5
Antifreeze %
Water %
Insolubles % 0.3
TBN 3.3
ISO Code

 

1st Oil Change

Blackstone Labs.

Miles on unit:17k

Miles on oil:15k

Make-up oil: .5 quarts.

Amsoil SS0 0w-30

Amsoil filter


You've run this oil for about 88% of this young engine's life, and that's the reason that we are still finding high
iron, copper, and silicon. We normally expect wear-in to be past by the time you get to about 10,000 miles, but when
you run long oil changes from the start, the process takes longer. You'll get there eventually, though you could speed
the process along by changing the oil at 7,500 miles next time. Note fuel at 3.0%. This is more than we like to see but
hopefully it's from rings seating. The TBN read 4.1 showing some active additive left. Check back.

ALUMINUM 5
CHROMIUM 0
IRON 18
COPPER 9
LEAD 1
TIN 11
MOLYBDENUM 1
MANGANESE 1
NICKEL 1
SILVER 0
TITANIUM 0
POTASSIUM 3
BORON 5
SILICON 58
SODIUM 6
CALCIUM 3206
MAGNESIUM 11
PHOSPHORUS 594
ZINC 711
BARIUM 1

cSt Viscosity @ 100°C 8.85
SUS Viscosity @ 210°F 55.3
TBN 4.1
Flashpoint in °F 315
Fuel % 3.0
Antifreeze % 0
Insolubles 0.3