Why regular fluid changes saves money

Killer Fluids!

Drum roll please… I am going to sound dramatic! The biggest killer of Classic Cars is manky, old fluids! They are the cancer that eats away at our cars unseen.

When our cars were new, they had short, regular service intervals. There was a comprehensive service manual that gave details of ‘Summer and Winter’ Oils, showed us how to drain the coolant and even how to grease the chassis components. If your car was registered before 1980, as an owner, you were expected to check the level and condition of fluids and in most cases, change them every 3,000 miles or 6 months.

In the modern day, with service intervals at 18,000 miles or 2 years plus, the concept of having to change fluids regularly seems alien and unnecessary. After all, we don’t use our cars as often as we used to, so why keep changing them?

The thing is, oil, brake fluid and coolant all lose their efficacy over time as well as use. Mineral based fluids do that faster than modern synthetics, with a life span in your vehicle of between 1 and 2 years.

How do I know what engine oil is best?

The good news is that there are just a few formulations of oil that span the 20th century for road cars. As long as you choose a quality classic brand, it is pretty simple to choose the right formulation.

Vintage cars, those built before 1950, use a single weight oil between SAE 30 and SAE 50. At the workshop we usually split the difference, using a heavy weight oil in cars before 1930 and the lightest one after. We would also use an SAE 30 in any post 1950 car with an oil strainer rather than a filter, such as oil-cooled VW’s.

Between 1950 and 1970, which covers the lion’s share of traditional classics, we use a quality 20W50 mineral oil. Changed yearly it offers the perfect combination of protection and lubrication. From 1970 oils became a little more sophisticated. Whilst most British classics from the period are still happy with a heavy mineral oil, German and Japanese cars are best run on a semi-synthetic, usually a 15W/50. The game moved on again in the 80’s and 90’s where oils became model specific, but the majority still used either a 10w/40 and later a 10w/30.

How often should I change engine oil and why?

With a car in classic use, the best practice is to change your engine oil and filter once a year or every 6,000 miles, whichever comes first. Fresh engine oil helps clean out oilways and keeps the pump free of debris which maintains good oil pressure.

Keep your engine cool and protect it from corrosion!

Coolant is neglected more than any other fluid and over a period of time that causes all sorts of issues and damage. In the majority of cars you need a 50/50 mix of quality glycol based antifreeze and distilled water and it needs to be changed every 2 years. This minimises damage done by corrosion and keeps the radiator clean. Every year we see at least half a dozen engines written off because of overheating caused by blocked waterways or rusted out pumps and studs.

Brake fluid – Best kept yellow

Most Classics run DOT 4 brake fluid. It is hygroscopic, which means that it absorbs water from the atmosphere. It takes about two years in the UK for the water content to get to a point where it is damaging the inside of your brake system. When your car had regular use and followed a manufacturer service schedule it would be changed every two years along with the coolant. When new your brake fluid will be bright yellow, it should be changed when it turns bronze. For cars kept in normal humidity this will be between 2 and 3 years.

Best Fresh!

The simple fact is that regular fluid changes, regardless of how little you use your classic will save you thousands of pounds over long term ownership. It will also show the next owner that you took maintaining the car seriously, adding to its value.