ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. Each case comprises two 5-quart bottles across various common viscosity grades. The retailer has also implemented a purchase restriction on certain Kirkland motor oil products. According to Costco’s current online listings, members may purchase no more than two units in a single transaction within a seven-day window.
This new $57.99 price tag is nearly double the approximately $30 cost reported for the same quantity last year. Costco offers Kirkland 5W-30, 5W-20, and 0W-20 full synthetic oils at this elevated online rate. Prices at warehouse stores may vary from those listed on the company’s website. The change primarily impacts customers purchasing larger quantities for routine vehicle maintenance, as each Kirkland package contains 10 quarts of synthetic motor oil.
In addition to Kirkland products, Costco has placed purchase limits on certain Mobil 1 synthetic motor oils. Mobil 1, a brand owned by ExxonMobil, appears in several Costco listings with a cap of five units per membership. These restricted items include six-packs of one-quart bottles available in multiple viscosity grades. Some listings cover standard formulations, while others include high-mileage variants. Consequently, the restrictions apply both to Costco’s private-label Kirkland motor oil and select Mobil 1 offerings from a major national lubricant producer.
Restrictions on motor oil extend beyond Kirkland products
Manufacturers of synthetic motor oils rely on refined base oils and special additives designed to safeguard engines under high heat and heavy use. Group III base oils are a key component in many synthetic lubricants available in the United States. A significant portion of these supplies is imported from overseas producers, including facilities in the Persian Gulf. Recent disturbances within Middle East energy markets have constrained the availability of certain petroleum products and have tightened segments of the lubricant supply chain.
Crude oil prices remained above $100 per barrel in mid-September. Brent crude traded near $107.82 on September 16, while West Texas Intermediate hovered around $104.86. Ongoing supply disruptions in the Middle East continue to impact production, exports, and shipping routes. Traffic through the Strait of Hormuz remained below normal levels, and issues affecting Saudi Arabia’s Red Sea energy infrastructure further added to the strain on petroleum markets and the broader network supplying refined products and lubricants.
Rising crude prices tighten lubricant supplies
Many passenger cars, sport utility vehicles, and light trucks rely on the affected Kirkland motor oils. Costco claims its full synthetic oils provide essential engine protection against wear and thermal stress. Certain products meet API SP and ILSAC GF-6A standards, which are designed for modern gasoline engines. The American Petroleum Institute oversees API motor oil standards, while ILSAC specifications focus on fuel economy, engine cleanliness, and wear protection. Multiple Kirkland synthetic oil listings display these standards.
Costco has not provided a detailed public explanation for the increase in Kirkland motor oil prices or the introduction of purchase limits. Its website currently displays the $57.99 price and a two-unit weekly restriction on specific Kirkland items. Meanwhile, separate Mobil 1 listings continue to show a five-unit per membership limit across several formulations. These adjustments coincide with higher crude oil prices and tightening lubricant supplies, with Costco’s current limits defining members’ purchase quantities through affected online listings.