ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has increased the online retail price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart pack. This bundle includes two 5-quart bottles and spans multiple common viscosity grades. The retailer has also implemented a purchase limit on this item, allowing members to buy no more than two units in a single transaction within a seven-day window. This restriction is visible on selected Kirkland Signature motor oil listings on the company’s website.
The new price represents a significant jump from the levels recorded about a year earlier, when the same quantity was priced at approximately $30. Currently, Costco lists various Kirkland full synthetic options online at $57.99, including formulations such as 5W-30, 5W-20, and 0W-20. Prices in warehouse stores might differ from those online and can vary depending on location. Each pack contains 10 quarts, making the price increase notable for customers who typically purchase oil for regular vehicle maintenance.
This purchase restriction also extends to several Mobil 1 products sold through Costco. Mobil 1, a brand owned by ExxonMobil, is one of the most recognized synthetic motor oil brands in the United States. Selected six-packs of one-quart bottles now have a limit of five units per membership. Listings affected include both standard and high-mileage formulations across various viscosity grades. The restrictions therefore apply not only to Costco’s private-label motor oil but also to a major national lubricant brand.
Limits on purchases extend beyond Kirkland oils
Manufacturing synthetic motor oils relies heavily on refined base oils and additives that satisfy current engine protection standards. Group III base oils are a key component in many synthetic lubricants, and the United States depends on foreign suppliers for a substantial portion of these materials. Major suppliers in the Persian Gulf contribute a large share of the global Group III output. Recent disruptions across Middle East energy markets have led to tighter supplies of various petroleum products and refining components used industry-wide.
Crude oil prices remained above $100 per barrel in mid-September, with Brent crude trading near $107.82 on September 16, and West Texas Intermediate around $104.86. The energy markets continued to reflect ongoing disruptions impacting major Middle East production and shipping routes, with traffic through the Strait of Hormuz well below typical levels. Additionally, Saudi export infrastructure on the Red Sea experienced interruptions, further straining regional petroleum supply chains.
The synthetic oil market faces broader supply challenges
Costco’s Kirkland range includes grades suitable for many passenger cars, SUVs, and light trucks. The company states that these oils protect against engine wear and thermal breakdown. Several formulations meet API SP and ILSAC GF-6A standards, which cover engine cleanliness, fuel efficiency, and wear protection. The Mobil 1 products available at Costco also include standard, fuel-economy, and high-mileage options, with purchase limits now set at five units per membership for six-packs of one-quart bottles.
Costco has not offered an explicit detailed explanation for the increased prices of Kirkland motor oil or the new purchase restrictions. Its online listings currently display the $57.99 price along with the two-unit purchase limit for selected products, while separate Mobil 1 pages continue to show a five-unit limit across various formulations. These changes coincide with a period of elevated crude oil prices and tighter lubricant supplies, with Costco’s posted limits providing members with clarity on current availability and purchasing guidelines.