The term “tune-up” has drastically changed since the phrase was coined during the dawn of automobiles. For over 50 years, a tune-up meant that the vehicle’s ignition system – breaker points and condenser, were replaced and/or adjusted, a new distributor cap, rotor, and spark plugs were installed, ignition timing was set, and the vehicles carburetor was adjusted and “tuned” (hence the term) for optimal performance. The process was as intricate as tuning a musical instrument – ignition and fueling had to work in perfect tune with each other for optimal performance, thus the term.
With vehicles of old, this was a regular occurrence. As electronic ignition replaced points-style systems, the need was still there for plugs, cap, rotor, and carb adjustments, but ultimately, even that became extinct once DIS (distributorless) ignition systems and computer-based fuel injection became the norm. Today, the vehicle’s engine computer and engine components constantly keep these systems running right where they should.
Today, at its simplest, a tune-up is a bit of a misnomer – simply a carry-over word of old to describe any time a host of basic routine maintenance is performed on your vehicle. Regular tune-ups can extend the life of a vehicle and help ensure it is operating at its full performance potential. Typically, when to do a tune-up is included in the regular maintenance section of owner’s manuals.
Tuning-up your car today can mean a lot of things. It’s a good idea to check the car’s filters, belts, hoses, and fluids. Also, it’s a good idea if you don’t know the last time you replaced your spark plugs and/or wires/coil boots, now could be a good time. Many may not need to be replaced, but it will give you a chance to stop small issues that could develop into big problems if left unchecked. If you want to learn how to do some of the repairs listed below, consult one of our How-To articles. If you need more detailed vehicle-specific information, check out our Repair Help guides and diagrams.
Check out the list below to find the parts and systems that you should check in a tune-up. You don’t need to do all of these things every time, but it’s always a good idea to make sure these are working correctly.
You can get great benefits from performing a tune-up on your vehicle. It’s one of the best ways to maintain original performance. In fact, fixing a car that is badly out of tune can give a noticeable boost to both engine performance and fuel economy*. A vehicle running in top shape today prevents and lessens costly repairs tomorrow. AutoZone’s tune-up guide will show you the common parts that are replaced when tuning up a vehicle such as spark plugs, plug wires, air filter and fuel filter. It’s also a great time to check other components under the hood such as belts, hoses, and fluids.
What Does a Tune-Up Consist of?
1. Replace Plugs, Wires, and Other Ignition Parts
The ignition system consists of spark plugs, plug wires, coils, and other electrical components that ignite the air/fuel mixture in your combustion chamber. The system has changed drastically over the years, where newer ignition systems require only spark plugs and wires/coil boots to be changed at a certain mileage. Older vehicles, as stated before, can have a distributor cap and rotor, and even older, can have breaker points.
Spark Plugs
Spark plugs have a metal tip (electrode) that wears down over time from high heat and constant electrical arc.
A symptom of worn spark plugs is a misfire, when the fuel/air mixture in a cylinder fails to ignite.
When replacing spark plugs, it is highly recommended to use plugs of the original equipment (OE) recommended metal. Consult your owner’s manual, repair manual or the experts at AutoZone to learn which is the recommended spark plug metal is right for you or check out our other blogs on spark plugs.
Be sure to use a light application of anti-seize on the threads of the plugs prior to installation (avoid getting anti-seize anywhere else but the threads).
In DIS (distributorless) applications that use one coil for multiple plugs, be sure to use either Double Platinum or Iridium plugs as recommended by the manufacturer.
If you need some help on replacing yours, check out our guide on how to change spark plugs.
Ignition Wires
Ignition wires will break down over time and eventually fail.
Symptoms of a failed wire are rough idle, misfire, performance loss, and eventually a dead cylinder.
When replacing a distributor cap or ignition wires, transfer one wire at a time from the old cap to the new cap. This prevents the ignition system from becoming cross wired, which result in a rough running engine. You can make this job easier by using a spark plug boot tool.
Use dielectric grease in the boots to help prevent arcing and help make future boot removal easier.
Be sure that your wires are secure and routed away from exhaust components.
Ignition Coils
Coils transform low battery voltage into thousands of volts. Over time this high voltage electricity wears out the coils out.
Signs your coils may be worn out include engine misfires, weakened acceleration, rough idle, and reduced gas mileage.
Some vehicles use coil packs, which are typically located near the valve covers, while others use a coil-on-plug design that are over or close to the spark plugs.
Put dielectric grease on the boot of coil-on-plug coils.
Distributor Cap and Rotor and Breaker Points (If Applicable)
Numerous rotations of the rotor inside the distributor will cause the metal contact point to wear down.
A failed distributor cap causes misfires or in more severe cases a non-start.
When performing a tune-up it is suggested to replace both the cap and rotor at the same time.
Transfer ignition wires one at a time from the old cap to the new cap. This prevents the ignition system from becoming cross wired, which result in a rough running engine. You can make this job easier by using a spark plug boot tool.
Older vehicles pre-1974 usually contain breaker-points which need to be adjusted / replaced on a regular basis.
2. Let Your Engine Run Clean with New Filters
Filters in your vehicle consist of: oil, fuel, air, and cabin air filters. Filters keep contaminating particles from reaching vital components in your engine and related systems. Having a clean filter improves engine performance and efficiency. Dirty filters make your vehicle work harder to get the air, fuel, and oil that it needs. This can choke off your engine or decrease the ability to deliver air, oil or fuel at the proper pressure.
Engine Air Filter
Filters thousands of gallons of air for every gallon of fuel and will clog over time.
Clogged air filters can reduce performance, but not MPGs on fuel injected engines*.
Clogged air filters in carbureted engines can reduce MPG’s by 2-6% and up to 14%*.
Replacing your air filter is generally a simple task, check out our air filter replacement guide if you need help.
Some vehicles are equipped with a cabin air filtration system and thus have a replaceable filter element to keep the air inside the vehicle clean.
A dirty cabin air filter can allow dust, pollen, exhaust fumes and other contaminants into your vehicle’s passenger compartment and restrict airflow into the vehicle.
Most cabin air filters are easily accessible and take less than 15 minutes to change. Learn how from this cabin air filter guide.
Oil Filter
Dirty oil can lead to excessive wear on internal engine components.
An oil filter is used to filter vital engine oil of contamination and can clog if not replaced at recommended intervals.
Can lead to high oil pressure in severe circ*mstances of clogging.
Should be replaced with every oil change at recommended intervals. Learn more from oil change guide.
Fuel Filter
Dirty fuel and contaminated fuel tanks can clog your fuel filter and lead to low fuel pressure, sometimes resulting in hesitation while accelerating or rough idling.
Can lead to premature fuel pump failure in severe circ*mstances.
Should be replaced with every oil change at recommended intervals.
PCV Valve
Over time the Positive Crankcase Ventilation Valve can become clogged by carbon build up.
Failure can cause the engine to consume oil at a much faster rate, cause poor fueling conditions, misfires, and actually blow out gaskets due to pressure accumulating in the crankcase.
The PCV Valve is usually easy to replace. In many cases, it can be swapped out in a matter of a few minutes.
3. Keep Your Auxiliary Systems in Check with New Belts and Hoses
Belts connect the pulleys of your accessory drive system which transfer the rotating force of the crankshaft pulley to the alternator, water pump, power steering pump, and other systems. Hoses transfer vital fluids throughout the engine. Over time, belts and hoses wear down due to the elements they are exposed to such as heat and cold as well as the constant use they see with day to day operation of the vehicle. They eventually wear down, glaze over, turn brittle, crack and even break.
Serpentine Belt
The serpentine belt rides in a series of pulleys on the front of your engine.
The belt wears down, and needs replacement because of exposure to heat and stress.
Inspect the belt(s) for cracks, fraying, glazing or fluid contamination. Any of these conditions can cause the belt to slip or break.
If you need help changing the belt out, check our serpentine belt replacement guide.
Belt Tensioner
The belt tensioner maintains the correct belt tension.
A weak belt tensioner will cause premature belt wear.
A ‘tight or sticking’ belt tensioner will cause premature wear to the water pump and other accessory bearings.
With the belt off, rotate the tensioner through its arc of travel. It should move smoothly and provide firm tension.
While the belt is off check the idler and tensioner pulley, plus accessory pulleys for proper alignment and smooth rotation – if any roughness or noise is detected in any pulley – replace it at this time.
Timing Belt
The timing belt controls the internal mechanical timing on many engines. This belt usually has an 80,000 – 100,000 mile life cycle, and then must be replaced, along with any tensioner or idler components that run the belt.
When a timing belt breaks on most vehicles, the piston can and will come in contact with valves that are stuck open which causes catastrophic damage.
The timing belt is an intricate job, and should be replaced on the recommended mileage intervals.
When inspecting your timing belt, take the time to check the cam and crank seals for leaks.
Some vehicles feature a timing chain instead of a timing belt. Timing chains typically do not need to be replaced as often, and usually have a much longer life cycle, although tensioner components which keep the chain tight can fail.
Hoses
Radiator hoses and heater hoses circulate coolant through the engine and the radiator to expel the heat absorbed.
Most hoses are made of rubber and will break down over time. You can find out of it is time to replace your hoses by inspecting them for swelling, bulging, or leaks. When the engine is cool, squeeze the hoses to feel for hard spots and soft spots.
Check the hose clamps for damage or loss of tension too. You don’t want one to let go while your engine’s hot.
If a hose were to fail, the engine could overheat. Overheating can cause serious, sometimes irreparable damage to the engine.
4. Maintain Your Car with the Right Fluids
Engine oil, coolant, brake fluid, transmission fluid, and power steering fluid are necessary for your vehicle to operate properly. Contaminated fluids can lead to excessive wear on internal components. You can save money in the long run by servicing these fluids before expensive damage occurs. Regular change intervals exist for each type of fluid and as such, they need to be replaced at recommended service intervals, find out more by consulting your owner’s manual or by visiting Repair Help.
Motor Oil
As oil circulates through your engine and is exposed to heat and pressure, the oil will become contaminated.
An oil filter will keep large particles from being recirculated, but will not keep the oil from providing a protective barrier of lubrication.
Replace the oil filter during an oil change.
Oil should be replaced at manufacturer recommended mileage or time intervals, consult your owner’s manual.
Coolant
Your cooling system keeps your engine from overheating in the summer and prevents your engine from freezing in the winter.
Coolant will eventually break down and become contaminated which results in degraded flow and the fluid’s ability to fight corrosion.
Flushing your cooling system with a flush product specifically designed to remove deposits regularly will improve the performance of your cooling system.
Always refer to your owner’s manual to determine the recommended coolant for your vehicle. Different manufacturers require the use of different types of coolant and using a fluid other than what’s specified by the manufacturer can result in engine damage.
Be sure to mix the coolant with the correct amount of water or use a pre-mixed product that’s ready to pour in.
Should you decide to change your coolant, check out our coolant flush and fill guide.
Brake Fluid
Brake fluid is a vital fluid in your vehicle, without it you would not be able to stop.
DOT 3 and DOT 4 brake fluid are hygroscopic, which means the fluid will absorb moisture from the air. This added moisture lowers the fluids ability to operate efficiently as a hydraulic fluid and causes internal corrosion in the braking system.
Dark or muddy looking fluid is a sure sign of hygroscopic contamination.
It is recommended that the brake fluid be changed out for fresh fluid and the brake system bled to ensure that new clean fluid is flowing throughout the entire system.
2 years is the recommended changing interval. Learn how to do it yourself with our guide on how to bleed brakes.
Automatic Transmission Fluid (ATF)
Automatic transmissions use friction packs, along with gearing to operate, which in turn needs a fluid to regulate that friction. This creates a ton of heat and results in wear of internal components and contamination of transmission fluid. This wear and tear makes it imperative to follow manufacturer’s recommendation for transmission fluid and filter change.
Brown transmission fluid is an indication that the fluid needs to be changed but, if the fluid is muddy or smells very burnt, do NOT change, instead, take your vehicle to a professional for a professional diagnosis and opinion on how to proceed.
Be sure to consult your owner’s manual for recommended change intervals as well as the correct fluid type to be used.
Power Steering Fluid
Over time contamination can cause wear to the power steering pump.
Be sure that your power steering fluid does not appear muddy and is between the MAX and MIN levels in the reservoir.
Be sure to consult your owner’s manual for recommended change intervals as well as the correct fluid type to be used.
You can get great benefits from performing a tune-up on your vehicle. It’s one of the best ways to maintain original performance. In fact, fixing a car that is badly out of tune can give a noticeable boost to both engine performance and fuel economy*. A vehicle running in top shape today prevents and lessens costly repairs tomorrow. AutoZone’s tune-up guide will show you the common parts that are replaced when tuning up a vehicle such as spark plugs, plug wires, air filter and fuel filter. It’s also a great time to check other components under the hood such as belts, hoses, and fluids.
Consider purchasing a repair manual or register on AutoZone.com to view free repair guides that give information on how to replace these parts as they relate to your vehicle’s specific needs.
*In vehicles with major emissions issues or carbureted vehicles.
Introduction: My name is Van Hayes, I am a thankful, friendly, smiling, calm, powerful, fine, enthusiastic person who loves writing and wants to share my knowledge and understanding with you.
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