Dealer bulletins from Nissan and Toyota are limiting 0W-20 and 5W-30 synthetic oil allocations, leaving U.S. service departments short of warranty-required grades.
A March attack on Shell’s Pearl GTL facility in Qatar knocked out a major Group III base-oil source, while the Strait of Hormuz closure has blocked nearly a fifth of global oil flows.
Group III supply is now about 44% below normal capacity, pushing wholesale prices above $10 a gallon; ILMA says pricing pressure is unlikely to ease before mid-2027.
Repair shops in Japan and the U.S. also report tighter supplies of paint, coatings and diesel exhaust fluid, with some body shops delaying refinishing work.
Analysts say even a preliminary U.S.-Iran agreement would not quickly restore shipments, and automakers may divert scarce petroleum-derived materials toward new-vehicle production over repairs.