Product Tested

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Ozark Automotive Distributors

Company and Product Information

Corporate Office:
Ozark Automotive Distributors
233 S Patterson Ave
Springfield, MO 65802


Ozark Automotive is one of the nation's Premier suppliers of replacement parts, accessories and supplies for virtually all makes of automobiles, light to heavy-duty trucks, off-road equipment, marine and agricultural equipment. Ozark Automotive also distributes the highest quality tools, equipment and paint & body supplies available in the automotive aftermarket. Ozark Automotive prides itself on providing proven, quality service and seeing the needs of each customer.
Source: Ozark Automotive's Website

SAE 15W-40 Motor Oil

Product: O'Reilly
Viscosity Grade: SAE 15W-40
Labeled: API CK-4, CJ-4, CI-4 PLUS, CI-4, CH-4/SN

Distributed By: Ozark Automotive Distributors, Springfield, MO

Purchased at: Piedmont, SC

Date of purchase: 7/26/2018


Website(s): and

Test Results and Assessment:

The results of the tests conducted on this sample meet the SAE J300 specifications for the SAE Viscosity Grade listed on the product label, and are consistent with the listed API Service Categories.


bottle icon Physical Properties pass
Elemental Analysis pass
Labeling warning
Viscosity @ 100°C, cSt (ASTM D445)

The results of the Kinematic Viscosity @ 100ºC test conducted on this sample meet the requirements of SAE J300.
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Cold Cranking Viscosity, mPa s (cP) (ASTM D5293)

The results of the Cold Cranking Viscosity test conducted on this sample meet the requirements of SAE J300.
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Phosphorus, ppm (ASTM D5185)

The results of the Phosporus test conducted on this sample meet the requirements of API CK-4/SN.
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Note1: Although laboratory tests alone cannot be used to establish if engine oil meets an API Service Category, they can be used to determine if it doesn't. Note2: The specification for cold cranking viscosity includes only a maximum value; the minimum value shown in the “standard” area of the chart is truncated for illustrative purposes.

PHYSICAL TESTS (click for test details) - a Standard O'Reilly
TBN, mg KOH/g (ASTM D2896) 9.53
Viscosity @ 100ºC, cSt (ASTM D445) 12.5 to <16.3 15.7
Viscosity @40ºC, cSt (ASTM D445) 117
Viscosity Index (ASTM D2270) 142
Viscosity @-20ºC mPa s (cP) (ASTM D5293) 7,000 Max 5,722
ELEMENTAL ANALYSIS (click for test details) - a, b
Calcium, ppm 1,008
Magnesium, ppm 983
Phosphorus, ppm 1,200 Max-c 994
Zinc, ppm 1,127
Molybdenum,  ppm 60
Barium, ppm <1
Boron, ppm <1
Silicon, ppm 4
Potassium, ppm <1
Manganese, ppm <1
Titanium, ppm <1
Copper, ppm <1
Sodium, ppm <1
Vanadium, ppm <1
Silver, ppm <1
Aluminum, ppm <1
Chromium, ppm <1
Iron, ppm <1
Nickel, ppm <1
Lead, ppm <1
Antimony, ppm <1
Tin, ppm <1
  1. Standards, shown in yellow are established by API, SAE and others.
  2. Test Method for metal analysis is ASTM D5185.
  3. This specification is expressed to one significant figure, therefore results up to 1,249 are considered on specification.