Dispelling Vintage and Classic Gear Oil myths

Classic car driving next to flowers

Our Technical Support Team receive many questions about how to properly look after your treasured classic cars. Automotive oils that meet today’s vehicle specifications contain the very latest base oil and additive technologies. However, due to changes in fuel and engine design over the years, these products are not always suitable for classic vehicles. Millers Oils has developed a full range of products specifically for older vehicles, taking today’s lubrication technology and formulating it to protect and enhance yesterday’s cars.

At Millers Oils, we produce gear oil for the two main areas of the classic car market, Vintage/Veteran (pre-war) & Classic (post-war). Gear oils meet certain specifications and performance criteria in a range of different viscosities. Close attention should be paid to what is required by the vehicle to ensure full protection and performance of the lubricant. Applications can differ in terms of shock loading capability which is linked to the amount of extreme pressure (EP) additive in the oil.

Due to the design of gearboxes & differentials in the pre-war period: lower power density and gear loading, the main requirement of a lubricant is the oil fill the gaps and provide a hydrodynamic film to protect with a general performance level of API GL-1. As technology progressed and power density/gear loading increased after the war, a lot more was placed on the lubricant, which led to additive being used in the formulation to protect in high load gear mesh scenarios. This was the birth of the ‘EP’ gear oil, with this additive working at boundary conditions (additive) and mixed lubrication (additive and oil film – hydrodynamic). The performance required was generally API GL-4 in gearboxes and API GL-5 in differentials.

To clarify Classic gear oils with EP additive should not be used in Vintage/Veteran applications that require an API GL-1 gear oil, and vice versa that you cannot use a Vintage/Veteran API GL-1 in an API GL-4 or API GL-5 application. However, you can use an API GL-5 gear oil in an API GL-4 application – but not the other way round.

Find out more about the range here: Vintage and Classic Vehicle Oil – Millers Oils

Or buy here: Classic Car Products – Millers Oils Shop (millersoils-shop.co.uk)

Our Technical Support Team are always happy to discuss any further questions you have. So give us a call on 01484 475060 or e-mail technical@millersoils.co.uk.