Classic Mustang Maintenance (1964–1973): Keep It Driving

A 1964–1973 Mustang needs more frequent, more hands-on care than any modern car: shorter oil change intervals with oil suited to flat-tappet engines, regular chassis lubrication, ignition tune-ups, and close attention to brakes, cooling and rust. The good news is that almost all of it is simple, inexpensive work you can learn to do yourself.

How a classic Mustang differs from a modern one

Modern Mustangs are designed to go a year or more between oil changes and to tell you, through a computer, when something's wrong. First-generation cars have none of that. They have carburetors, mechanical or vacuum-controlled ignition timing, grease fittings in the steering and suspension, and gauges that are your only warning system. Nothing reports a fault for you: you find problems by looking, listening and smelling.

That also means there's no OBD port and no trouble codes. Diagnosis is done with a timing light, a vacuum gauge, a multimeter and a compression tester, which are cheap tools that every classic owner should own.

Engine oil: the flat-tappet question

Most 1964–1973 Mustang V8s and sixes came from the factory with flat-tappet camshafts. Flat-tappet cams rely on anti-wear additives, chiefly zinc and phosphorus compounds (ZDDP), to protect the cam lobes and lifters. Modern passenger-car oils have reduced levels of these additives to protect catalytic converters, which is fine for modern engines with roller cams but may not be enough for a flat-tappet engine.

Practical approach:

• Use an oil specifically labeled for classic, high-performance or flat-tappet engines, or a suitable additive, unless your engine has been converted to a roller cam.
• Change oil and filter roughly every 3,000 miles or at least once a year, whichever comes first. Old engines without modern crankcase ventilation contaminate oil faster, and a car that sits gets moisture in the oil.
• Viscosity: many owners run 10W-30 or 10W-40 depending on climate and engine wear. If the engine has been rebuilt, follow the builder's recommendation.
• New or rebuilt flat-tappet cams need a proper break-in procedure. Ask the builder exactly what they want done.

Fuel: ethanol and old rubber

Most pump gas in the US today contains up to 10% ethanol. Original-style rubber fuel hoses and older carburetor components weren't designed for it, and can harden, crack or swell over time. Ethanol also absorbs water and goes stale faster when a car sits.

• Replace rubber fuel lines with hose rated for ethanol-blended fuel.
• Inspect the fuel filter and replace it periodically.
• If the car sits for more than a few weeks, use a fuel stabilizer and keep the tank full to reduce condensation.
• Watch for fuel smell in the garage or around the carburetor. A fuel leak near a hot engine is a fire risk.

Ignition tune-ups

Factory cars of this era use a points-type distributor. Points wear and need periodic adjustment of the gap or dwell angle, and the timing needs to be set with a timing light. A typical tune-up includes:

1. Inspect and gap or replace the points and condenser.
2. Set dwell, then set initial timing to spec with the vacuum advance disconnected and plugged.
3. Inspect the distributor cap and rotor for carbon tracking and worn contacts.
4. Check plug wires for cracks and resistance.
5. Read and replace the spark plugs. Their color tells you about mixture and oil burning.
6. Adjust the carburetor idle speed and mixture once timing is correct.

Many owners convert to an electronic ignition kit that fits in the original distributor. It removes points maintenance but should be documented, since it changes how the car is tuned and diagnosed. Timing and dwell specifications vary by engine and year, so use a shop manual for your exact car.

Chassis lubrication

This is the job most often forgotten by owners used to modern cars. Classic Mustangs have grease fittings (zerks) on suspension and steering joints like ball joints, tie rod ends and some steering linkage parts. Original-style parts need fresh grease regularly; factory service intervals were far shorter than anything on a modern car, so check a shop manual for your year. Replacement parts may or may not have fittings. Use a grease gun, wipe each fitting first, and pump until the old grease is pushed out of the boot without bursting it.

Brakes

Many first-generation Mustangs have four-wheel drum brakes; front discs were an option and became more common in later years. Early cars also used a single-circuit master cylinder, which means one leak can take out braking at all four wheels. Dual-circuit master cylinders became standard in the later first-generation cars.

• Flush brake fluid every couple of years. DOT 3 is typical; don't mix it with silicone DOT 5.
• Inspect rubber hoses and steel lines for cracks, bulges and rust.
• Adjust drum brakes if they don't self-adjust properly; a low or uneven pedal is the sign.
• If your car still has a single-circuit system, a dual-circuit master cylinder conversion is one of the most worthwhile safety upgrades you can make.

Cooling system

Classic V8s can run hot in summer traffic, especially with original radiators that have partly clogged over decades. Keep the system healthy:

• Flush and refill coolant every two years or so with a coolant suitable for older engines.
• Replace hoses, the thermostat and the radiator cap on a schedule, not when they fail.
• Check fan belt tension and condition, and the fan clutch if equipped.
• Make sure the fan shroud is in place, since it matters a lot at low speeds.
• Get a temperature gauge you can trust; old sending units can read wrong.

Drivetrain and electrical

Check the manual transmission and rear axle gear oil levels at the fill plugs once a year, and look for leaking seals. Automatic transmission fluid should be checked hot with the engine running, according to the procedure on the dipstick or in the manual. Electrical problems in old cars usually come down to corroded grounds, tired connections and aging wiring. Clean the battery terminals and ground straps, and fix any wiring that's been patched with tape.

Rust: where to look

A simple classic Mustang schedule

If the car goes away for the winter, follow our winter storage checklist, and use the spring startup checklist when it comes back out.

Because classics are driven occasionally, time-based reminders work better than mileage ones. In My Mustang, you can set a reminder for the chassis lube or brake fluid flush, log each tune-up with timing and dwell notes, and attach photos of restoration work so the history stays with the car.