# Carmakers Reformulate Engine Oils as Gulf Base-Oil Supply Stays Cut Off

Roughly 44 percent of the Group III base oil used in the United States comes from three Persian Gulf refineries, and almost none has shipped since late February.

- Published: 2026-08-16T05:05:21.347Z
- Canonical: https://polylog.news/2026-08-16/carmakers-reformulate-engine-oils-as-gulf-base-oil-supply-st
- Publisher: Polylog (Global desk)
- Section: markets
- Sources: [Financial Times](https://www.ft.com/content/161ee092-d2b6-4375-a853-e7a6fbee60e2?syn-25a6b1a6=1), [Axios](https://www.axios.com/2026/05/15/motor-oil-shortage-synthetic-oil-prices), [Gas Price Check](https://www.gas-price-check.com/research/the-2026-motor-oil-squeeze)

The world's largest carmakers are turning to new lubricant blends to avoid running out of engine oil, [the Financial Times reported](https://www.ft.com/content/161ee092-d2b6-4375-a853-e7a6fbee60e2?syn-25a6b1a6=1), as a shortage of Group III base oils works its way from the Gulf into dealer service bays. Group III is the highly refined base stock that modern low-viscosity synthetic oils are built on, and modern engines are designed around it.

The supply problem traces directly to the Gulf war. Around 44 percent of the Group III base oil used in the United States comes from three refineries in the Persian Gulf, and [almost none has left the region since the Strait of Hormuz was effectively blockaded in late February](https://www.gas-price-check.com/research/the-2026-motor-oil-squeeze). Damage to Qatar's gas-to-liquids capacity removed further volume. [Axios reported in May](https://www.axios.com/2026/05/15/motor-oil-shortage-synthetic-oil-prices) that shortages were already visible at the retail level, concentrated in the thinnest grades, 0W-8, 0W-16 and 0W-20, which are exactly the specifications most new vehicles require.

Manufacturers have responded by authorising substitutions. Toyota and Nissan have issued service bulletins permitting temporary alternatives so vehicles can stay in service, and blenders are reformulating around Group II stocks and synthetic alternatives that carry different performance characteristics. Industry estimates quoted this month put Group III base-oil prices above 10 dollars a gallon and see the market undersupplied into 2027.

The episode illustrates a feature of chokepoint disruption that headline crude prices do not capture. Oil markets can absorb a barrel shortfall by rerouting cargoes, but specialised refined products come from a small number of plants with no substitutes ready. A single closed waterway removes an input for which the replacement cycle is measured in years of capital spending, not weeks of shipping.

## What this means

Automakers and lubricant blenders absorb the cost first, through reformulation work and higher input prices, and then pass it to fleet operators and drivers through service costs. The wider signal is that concentrated specialty refining is an unrecognised dependency inside supply chains that appear diversified at the crude level. Anyone modelling the economic cost of the Hormuz closure from crude prices alone is understating it, because the binding constraints are in narrow product markets where spare capacity does not exist and new plants take years to build.

## What to watch

- Whether Group III producers outside the Gulf, particularly in South Korea and the United States, announce capacity expansions, which would show the industry treating the shortage as lasting rather than temporary.
- Warranty and service-interval guidance from major manufacturers, since further relaxation would mean substitution is spreading beyond emergency use.
- Other specialty refined products with the same Gulf concentration, such as certain petrochemical feedstocks, where the next shortage would appear if the closure persists.
- Retail oil-change prices in the United States and Europe, the point at which the disruption becomes a consumer inflation item rather than an industrial one.