Product Tested

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Circle K Stores Inc.

Company and Product Information

Corporate Office:
Cirlce K Stores Inc.
Tempe, AZ

Website(s): www.circlek.com

Circle K is an international chain of convenience stores, founded in 1951, in El Paso, TX. It is owned and operated by the Canadian-based Alimentation Couche-Tard, which is one of the largest company-owned convenience store operators in the world with more than 16,000 stores across Canada, the United States, Europe, Mexico, Japan, China, and Indonesia. The company operates its corporate stores under mainly Couche-Tard, Mac’s, Circle K, On the Run and also under the affiliated brands 7-jours, Dairy Mart, Daisy Mart and Winks.


The Petroleum Quality Institute of America (PQIA) is an independent resource for information and insights on the quality of lubricants in the marketplace. Our mission is to serve the consumer of lubricants by randomly sampling and independently testing lubricants taken from the field. Test results are posted along with the brand names on the PQIA website. This webpage provides an analysis on the brand detailed below.

The following are the test results for the sample examined.

Circle K SAE 10W-40
Premium Motor Oil

Product: Circle K
Viscosity Grade: SAE 10W-40
Labeling: API SN

Distributed By: Circle K Stores Inc., Tempe, AZ
Manufactured By: Pinnacle Oil, Indianapolis, IN

Purchased at: Hugoton, KS

Date of purchase: 4/13/2016


Website(s): www.circlek.com

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

Note: 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.

PHYSICAL TESTS (click for test details) - a Standard Circle K
TBN, mg KOH/g (ASTM D2896) 8.69
Viscosity @ 100ºC, cSt (ASTM D445) 12.5 to <16.3 14.53
Viscosity @40ºC, cSt (ASTM D445) 96.18
Viscosity Index (ASTM D2270) 157
Viscosity @-25ºC mPa s (cP) (ASTM D5293) 7,000 Max 5,173
Volatility, mass % loss, 1 hr, @ 250ºC (ASTM D5800) 15 Max -c 13.0
ELEMENTAL ANALYSIS (click for test details) - a, b
Calcium 2,454
Magnesium 14
Phosphorus, ppm 600 Min 773
Zinc, ppm 855
Molybdenum,  ppm 44
Barium, ppm <1
Boron, ppm 5
Silicon, ppm 5
Potassium, ppm <5
Manganese, ppm <1
Titanium, ppm <1
Copper, ppm <1
Sodium, ppm <5
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 two significant figures, therefore results up to 15.5 are considered on specification.