ISSAQUAH, WASHINGTON / RankWire.AI / – Costco has lifted the online price of its Kirkland Signature full synthetic motor oil to $57.99 for a 10-quart case. Each case contains two 5-quart bottles in several common viscosity grades. The retailer has also imposed a purchase limit on selected Kirkland motor oil products. Members may buy no more than two units in one transaction during a seven-day period, according to Costco’s current online listings.
The new $57.99 price is nearly twice the roughly $30 level reported for the same amount last year. Costco lists Kirkland 5W-30, 5W-20 and 0W-20 full synthetic oil at the higher online price. Prices at warehouse locations may differ from those shown on the company’s website. The change affects customers who buy larger quantities for routine vehicle maintenance, since each Kirkland package contains 10 quarts of synthetic motor oil.
Costco has also placed limits on selected Mobil 1 synthetic motor oil products. Mobil 1, an ExxonMobil brand, appears in several Costco listings with a five-unit purchase cap per membership. The affected products include six-packs of one-quart bottles in multiple viscosity grades. Some listings cover standard formulations, while others include high-mileage versions. The restrictions therefore apply to both Costco’s private-label Kirkland motor oil and selected products from a major national lubricant brand.
Motor oil restrictions extend beyond Kirkland products
Synthetic motor oil production relies on refined base oils and additives designed to protect engines under heat and heavy use. Group III base oils form a key component in many synthetic lubricant products sold in the United States. American buyers import a significant share of those supplies from overseas producers, including facilities in the Persian Gulf. Recent disruptions across Middle East energy markets have reduced the availability of some petroleum products and tightened parts of the lubricant supply chain.
Crude oil prices remained above $100 a barrel in mid-September. Brent crude traded near $107.82 on September 16, while West Texas Intermediate stood near $104.86. Middle East supply disruptions continued to affect production, exports and shipping routes. Traffic through the Strait of Hormuz remained below normal levels. Interruptions also affected Saudi Arabia’s Red Sea energy infrastructure, adding pressure across petroleum markets and the broader network that supplies refined products and lubricant materials.
Higher crude prices coincide with tighter lubricant supply
The affected Kirkland motor oils serve many passenger cars, sport utility vehicles and light trucks. Costco says its full synthetic oils help protect engines from wear and thermal breakdown. Selected products meet API SP and ILSAC GF-6A performance requirements for modern gasoline engines. The American Petroleum Institute manages API motor oil standards, while ILSAC specifications cover areas such as fuel economy, engine cleanliness and wear protection. Those standards appear on several Kirkland synthetic oil listings.
Costco has not issued a detailed public explanation for the Kirkland motor oil price increase or the new buying limits. Its website currently shows the $57.99 price and two-unit seven-day restriction on selected Kirkland products. Separate Mobil 1 listings continue to show five-unit membership limits on several formulations. The changes come during a period of elevated crude prices and tighter lubricant supplies, while Costco’s posted limits now define how much members can purchase through affected online listings.