Costco has raised the price of its Kirkland Signature full-synthetic motor oil and imposed weekly purchase limits as higher crude costs and disruptions in the Middle East strain lubricant supplies. A two-pack of 5-quart Kirkland oil now sells for $57.99, versus roughly $30 a year earlier, while members may complete one transaction and buy no more than two units every seven days. Mobil 1 full-synthetic one-quart six-packs, priced at about $44, are limited to five per membership. Group III base oils used in motor oil are largely refined from crude, and more than 40% of U.S. supplies come from the Middle East. Brent crude traded at $107.34 a barrel, while AAA reported regular gasoline at $4.3163 a gallon and diesel at a record $6.2301 a gallon. Senators Elizabeth Warren and Chuck Schumer criticized President Donald Trump over energy costs linked to the Iran war, while Trump said gasoline prices should decline after the war ends.