Motor oil prices are climbing, with synthetic oil costs rising 20% to 30% compared to June, according to Robert Paffe, service manager at Dubwerx in Cincinnati. Supply disruptions tied to the Iran war have prompted retailers like Costco to limit how much motor oil customers can buy.

The shortage hits hardest for owners of newer hybrids and fuel-efficient vehicles that require low-viscosity synthetic oils like 0W-8 and 0W-16. Karl Brauer of iSeeCars says drivers due for a change soon should plan ahead and secure their oil now rather than wait.