Maintaining Your Classic Car: A UK Owner's Guide

Follow the service schedule in the handbook or workshop manual; Millers Oils, for one, leaves oil change intervals to the vehicle manufacturer's specification. Those schedules assumed regular use, though, and a classic that covers a few hundred miles a year still ages. Oil degrades over time, and low mileage raises the risk of fuel dilution, which speeds oxidation. A sensible routine is to keep to the manual's mileage intervals, change the oil and filter before each winter lay-up whatever the mileage, and keep a written record of every job, part number and fluid used.

In an engine with a flat tappet camshaft, each cam lobe slides against its follower under heavy load. Protection there comes largely from ZDDP, an anti-wear additive that forms a film on the metal. High levels can harm catalytic converters, which is why modern oils carry less. Millers Oils recommends between 1,000 and 1,400 ppm for classic engines and warns that more is not better, because excess can increase wear. Choose an oil sold for classic engines, in the viscosity the handbook specifies, and ask the supplier for its ZDDP figure if the label does not state it.

Standard 95-octane petrol became E10, containing up to 10 per cent ethanol, in Great Britain in September 2021. GOV.UK lists classic and cherished vehicles among those that may not be compatible, and the FBHVC recommends that cars built before 2000 use the super E5 protection grade. Ethanol can damage some cork, shellac, epoxy resin, nylon, polyurethane and glass-fibre polyester parts, and it absorbs water from the air. Fit ethanol-resistant hoses and seals whenever fuel system parts are renewed. For a long lay-up, the FBHVC advises against leaving the fuel system dry, because seals and gaskets shrink and crack.

Glycol brake fluid absorbs moisture, which lowers its boiling point, and fluid that boils stops responding properly to the pedal. Castrol notes that most manufacturers recommend changing it at least every two years. DOT 3, DOT 4 and DOT 5.1 are glycol based and mix with each other, but DOT 5 is silicone and must never be mixed with them, so find out what the system contains before topping up. Grease and oil points need the same care: Classic & Sports Car warns that a Triumph Spitfire's lower trunnions need regular heavy oil, or they can seize and snap the kingpin.

Damp is the main enemy in storage, so keep the car in a dry, well-ventilated building and connect a battery conditioner rather than letting the battery go flat over the winter. Tyres age even when unused: the last four digits of the DOT code give the week and year of manufacture, and TyreSafe asks for particular attention to collectors' vehicles, with checks at least monthly for cuts, bulges and cracking. If the car is taken off the road, a SORN lets you stop taxing and insuring it, but it can then only be driven on a public road to or from a pre-booked MOT or other test.

A car built or first registered more than 40 years ago needs no MOT if it has not been substantially changed, but it must still be roadworthy, and many owners choose a voluntary MOT anyway. Low mileage hides wear: rubber bushes, brake hoses and fuel lines perish with age, and corrosion grows underneath unseen, so have the car checked on a hoist once a year and before any long trip. Keep the report with the service record. Classic And Retro Autos in Witton Gilbert, County Durham, offers a hoist inspection of about an hour for £65 plus VAT, by appointment on 0191 3730086.

It is best avoided. GOV.UK says owners of vehicles not listed in its E10 checker should keep using E5, the 97-plus octane super grade, and the FBHVC recommends super E5 for all vehicles built before 2000. Ethanol can damage some older fuel system materials and absorbs water, so fit ethanol-resistant hoses and seals when renewing parts.

Only some. DOT 3, DOT 4 and DOT 5.1 are glycol based and mix with each other, but DOT 5 is silicone and must never be mixed with them, so find out what the system contains before topping up. Glycol fluid absorbs moisture, which lowers its boiling point, so most manufacturers recommend changing it at least every two years.

Use the viscosity in the handbook, in an oil made for classic engines. Flat tappet engines need enough ZDDP anti-wear additive; Millers Oils recommends 1,000 to 1,400 ppm and warns that more is not better. Modern oils carry less because high levels can harm catalytic converters, so ask the supplier for the figure if the label does not give it.

Follow the handbook's mileage intervals, but do not let time slip. Change the oil and filter before each winter lay-up, because oil degrades even when a car stands and low mileage raises the risk of fuel dilution. Renew glycol brake fluid at least every two years, and check tyres monthly for cracking, since tyres on little-used cars can age out before they wear out.