AUTO PARTS & SIGNS OF WEAR
Hear a rattle? Smell something unusual? Is your car or truck just not feeling “right”? These can all be small signs of a bigger problem. Knowing what to look for in-between regular maintenance visits can help keep a small issue from becoming a major auto repair.
Below you will find an overview of the major systems and auto parts within your vehicle and signs of significant wear and tear. When the time is right, or if you ever have concerns, bring your vehicle back to your Chevrolet, Buick, GMC or Cadillac dealer for any type of auto service — major or minor. Your Certified Service experts are trained to know every part of your vehicle.
HVAC & ENGINE COOLING
Accumulator/Drier The accumulator in your vehicle gathers and stores liquid refrigerant until it’s converted into a gas refrigerant. | Sign of wear: Lack of or insufficient cooling in the cabin |
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Thermostat The thermostat regulates the temperature of the engine coolant to maintain proper engine operating temperature. | Signs of wear:
Engine overheats Reduced fuel economy Insufficient heat in cabin |
Compressor The compressor compresses refrigerant. The compression leads to a change in the refrigerant’s boiling point that helps create the cold air that is delivered through the HVAC system. | Signs of wear: Lack of or insufficient cooling Excessive clicking sounds Unusual noises during A/C operation |
Water Pump The water pump is responsible for circulating engine coolant through the radiator and engine system to help maintain optimal engine operating temperatures. | Signs of wear:
Engine overheating Leaking coolant |
Condenser The condenser cools refrigerant gas back into a liquid state. | Sign of wear: Reduced cooling capacity in vehicle cabin due to physical damage or debris |
Compressor Clutch A critical component of your HVAC system, the compressor clutch engages and disengages your compressor. | Signs of wear: Reduced cooling in vehicle interior Noise when running A/C system Rubbing/grinding noise when A/C is off |
Blower Motor Your vehicle’s blower motor drives air through the HVAC system and into your cabin. | Signs of wear:
Lack of or diminished airflow through cabin vents Unusual noises coming from blower motor |
Engine Cooling Fan The engine cooling fan, located behind your radiator, draws cool outside air through the condenser and radiator at low-speed operation to cool the engine. | Signs of wear:
Engine overheats Fan doesn’t turn Poor A/C performance |
Expansion Valve The expansion valve restricts the flow of refrigerant, allowing it to change from a high-pressure liquid to a low-pressure gas, which provides the cooling effect of A/C. | Sign of wear:
Lack of cooling in cabin |
Evaporator Warm air from inside your vehicle is delivered to your evaporator. Moisture and heat are then removed from the air and returned to your cabin. | Sign of wear:
Lack of cooling in cabin |
Heater Core Hot engine coolant from the cooling system circulates through the heater core to provide warm air to the passenger compartment. | Signs of wear:
Sweet smell coming from vents Insufficient heat from vents Wet carpet on passenger side |
Radiator Engine coolant flowing through the radiator is cooled by wind and the radiator fan to help keep the engine within proper operating temperatures. | Signs of wear:
Leaking (often a bright green colour) Engine overheats Sweet smell |
IGNITION & BATTERY
Ignition Coil The ignition coil increases electrical system voltage to help ignite the air/fuel mixture. | Signs of wear: Engine won’t start Engine misfiring Visible cracks in coil body |
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Spark Plug Spark plugs provide the spark that ignites the air-fuel mixture within an engine’s cylinders. | Signs of wear: Lack of power Sluggish acceleration Poor fuel economy |
Ignition Modules Later-model vehicles with a distributor and coil pack use an ignition module as a switch that, when engaged, supplies power to the coil which in turn creates the spark that ignites the air-fuel mixture. | Signs of wear: Engine won’t start Engine misfiring |
Ignition Wire Set This specialized wire set carries voltage from the ignition coil, electronic coil pack or distributor to the spark plugs. | Signs of wear: Difficult engine starting Misfiring Decreased fuel economy |
Starting Motor & Solenoid When starting the engine, the solenoid is energized, which engages the starter pinion into the flywheel, while the starter motor drives the pinion to crank the engine. | Signs of wear: Poor starting qualities including repeated starting attempts Grinding while cranking Intermittent starter engagement while trying to start the engine |
Battery Your car’s battery supplies and stores electrical energy from the alternator when the vehicle’s engine is running. The car battery provides energy to start the engine, plus supplies power to accessories when the engine is not running. For the best combination of longevity, power, and price, We proudly offer a wide range of ACDelco batteries. | Signs of wear: Slow cranking Weak/dim lights while cranking |
FUEL & ENGINE EMISSIONS
Modular Fuel Pump/Sender Limited Lifetime Parts Warranty Protection This two-part component delivers fuel from your tank to the fuel injectors while monitoring and sending fuel level information to your fuel gauge. | Signs of wear: Difficult engine starting Slow acceleration qualities Intermittent power loss Inaccurate fuel gauge reading |
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Muffler & Tailpipe The exhaust muffler reduces the noise levels of the engine exhaust by the use of tuning tubes. The tuning tubes create channels inside the exhaust muffler that lower the sound levels created by the combustion of the engine. The tailpipe carries the exhaust gasses from the muffler to the rear of your vehicle. | Signs of wear:
Exhaust is louder Clunking noise in rear of vehicle |
Engine Control Module (ECM) This module monitors and synchronizes the operation of the ignition, emission and fuel injection systems. All sensors input information to the ECM to constantly adjust the air-fuel mixture for optimum emissions, drivability and performance. | Signs of wear: Engine won’t start Reduced or loss of engine power “Service Engine Soon” light illuminates |
Exhaust Gas Recirculation Valve (EGR)
The EGR valve recirculates some of the engine’s exhaust gas back into the intake manifold to be reburned, reducing emissions. | Signs of wear: Rough-running engine Engine hesitation or stalling “Service Engine Soon” light illuminates |
Fuel Injector The fuel injector sprays a fine mist of fuel into a vehicle’s intake manifold or cylinders a fraction of a second before the spark plug ignites it. | Signs of wear: Sluggish engine performance Poor acceleration “Service Engine Soon” light illuminates |
Mass Air Flow Sensor This sensor measures the amount of air entering the engine. | Signs of wear: Engine hesitation Stalling Decline in engine performance “Service Engine Soon” light illuminates |
Oxygen Sensor The oxygen sensor measures the amount of leftover oxygen from the combustion process in the exhaust. | Signs of wear: Rough-running engine Poor fuel economy “Service Engine Soon” light illuminates |
Engine Coolant Temperature Sensor Constantly measures the engine’s coolant temperature. | Signs of wear: Cooling fan(s) on high all the time Poor fuel economy “Service Engine Soon” light illuminates |
Intake Air Temperature Sensor Constantly measures the temperature of the incoming air to the engine. |
Signs of wear: Rough-running engine Poor fuel economy “Service Engine Soon” light illuminates |
Humidity Sensor Constantly measures the humidity of the incoming air to the engine. | Sign of wear: “Service Engine Soon” light illuminates |
Knock Sensor Constantly measures the spark knock from the engine so the engine control module can adjust the ignition timing to reduce it. | Sign of wear: “Service Engine Soon” light illuminates |
Throttle Position Sensor (throttle body) Constantly measures the opening of the throttle body as you depress the accelerator. | Sign of wear: “Reduced Engine Power” light illuminates |
Accelerator Pedal Position Sensor Constantly measures the amount the accelerator is depressed so the ECM can open the throttle proportionately to increase acceleration. | Sign of wear: “Reduced Engine Power” light illuminates |
Fuel Pressure Sensor Constantly measures the fuel pressure in the fuel rail so the ECM can maintain the pressure at optimum levels. | Signs of wear: Ticking noise from engine “Service Engine Soon” light illuminates |
Fuel Composition Sensor On vehicles equipped to run on E85 ethanol, this sensor constantly measures the amount of ethanol in the fuel. | Sign of wear: “Service Engine Soon” light illuminates |
Positive Crankcase Ventilation (PCV) Valve Your vehicle’s PCV valve was designed to regulate unspent combustion gasses so they can be burned in the engine. | Signs of wear: Engine runs rough or unexpectedly stalls “Service Engine Soon” light illuminates |
Catalytic Converter(s)
The catalytic converter is an emission control device added to the engine exhaust system in order to reduce hydrocarbons, carbon monoxide and oxides of nitrogen pollutants from the exhaust gas. | Signs of wear:
Exhaust is louder Rotten-egg smell |
Resonator
Some exhaust systems are equipped with a resonator. The resonator, located either before or after the muffler, allows the use of mufflers with less back pressure. Resonators are used when vehicle characteristics require specific exhaust tuning. | Signs of wear: Exhaust is louder Clunking noise in rear of vehicle |
DRIVELINE & POWERTRAIN
Wheel Bearing The wheel bearing is mounted on a wheel hub, which in turn is connected to the axle. The bearings reduce friction and increase your control of the vehicle as the wheel turns over the surface of the road. | Signs of wear: Grinding Whining or squealing noises Looseness or roughness felt in the steering-wheel |
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CV Joint/Boot The CV boot protects the CV joint (in front-wheel-drive automatic transaxle vehicles) from harmful moisture, sand, dust and other roadway debris. If the boot is worn or damaged, these particles can eat away at the CV joint, potentially causing the need to replace the CV joint or even a half axle. | Signs of wear: Lubricant leak Clicking sounds during turning Clunks during acceleration Front-end vibrations |
Engine The engine is the heart of your vehicle. Most engines use combustion (igniting an air-fuel mixture to create mechanical energy) to create power that is delivered to the wheels, which in turn propels the vehicle. | Signs of wear: Rough running High oil or fuel consumption Visible smoke while engine is running |
Transmission/Transaxle The transmission/transaxle in your vehicle uses a combination of hydraulics and gears to transfer power from the engine to the wheels. Transmissions are typically utilized in rear-wheel-drive applications and transaxles typically on front-wheel drive. However some high-performance vehicles, like the Chevrolet Corvette, use a rear transaxle for weight distribution purposes. | Signs of wear: Noticeable transmission/transaxle slippage Lack of acceleration Transmission fluid emits a burning odour |
Differential/Rear Axle The differential receives power from the drive shaft and delivers power to rear-drive wheels through a series of gears. | Signs of wear: Clanking noise Whining or humming noise at steady speed or during coast down |
Flywheel This round, multi-toothed disc connects the engine, clutch system and automatic transmission. | Signs of wear: Noticeable transmission slippage Lack of acceleration Failure to engage Erratic transmission operation |
Clutch Manual vehicles use this combination of components to engage and disengage the engine to and from the transmission for changing gears. | Signs of wear: Clutch slippage Clutch engage failure |
SUSPENSIONS
Shocks & Struts The ride and handling system supports your vehicle’s weight, keeps the wheels in contact with the road and helps provide a comfortable ride. | Signs of wear: Excessive ball joint play Leaking oil along the shock body Broken mounts or mounting hardware Worn or missing bushings Excessive vehicle bounce Cupped tire wear |
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Control Arm Control arms join wheel hubs to the vehicle frame, allowing for a full range of motion while maintaining proper wheel alignment. | Signs of wear:
Uneven tire wear Suspension noise or misalignment Steering-wheel wobble or vibration |
Shock Absorber: The shock absorbers on your vehicle minimize spring bounce, helping to keep wheels in contact with the road and providing a smoother ride. | Sign of Wear: Excessive vehicle bounce Cupped tire wear |
Strut Mount/Bearing The strut mount helps improve strut operation by absorbing energy and restoring smooth steering while the bearing allows the strut to turn with the wheels while steering. | Signs of wear: Suspension noise Uneven tire wear Steering-wheel does not easily return to centre position |
Ball Joint The ball joint is a pivot point for the wheel assembly, allowing the wheels to turn and move up and down with the suspension. | Signs of wear: Rough ride Play in steering-wheel Slow or stiff steering-wheel return Excessive tire wear on one side |
Coil Springs Your suspension system’s coil springs support the weight of your vehicle and maintain vehicle ride height. | Signs of wear: Low vehicle ride height Rough, unstable or uncontrollable ride Excessive tire wear on one side |
Bushing The bushings attached to the suspension system provide a cushioned link between control arms and chassis. | Signs of wear: Excessive steering-wheel play Hard steering Noise Wobble Irregular tire wear |
STEERING PARTS
Power Steering All GM vehicles are equipped with either an electrically-assisted or a hydraulically-assisted power steering system. On hydraulically-assisted systems, the power-steering pump is a constant displacement pump that provides hydraulic pressure and flow for the power-steering gear. The hydraulic power-steering pump is belt-driven off your engine. | Signs of wear: Fluid leakage Difficult low-speed steering Whining noise while turning Steering-wheel wobble Pump housing leakage |
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Rack-And-Pinion This steering assembly uses a long steel bar that is meshed with a pinion gear and connected to rods that turn the front wheels. The rack-and-pinion can be hydraulically assisted by a power steering pump or electrically assisted. |
Signs of wear:
Excessive play in steering-wheel Steering-wheel vibration Unusual noises while turning the wheel |
Idler Arm The idler arm in your vehicle acts as a pivot point to the steering linkage assembly. | Sign of wear:
Irregular tire wear, such as feathering or scrubbing |
Pitman Arm On vehicles that utilize a steering gear, the pitman arm connects the steering gear and steering linkage. | Sign of wear: “Wandering” and excessive steering with little directional change |
Tie-Rod End The tie-rod end connects or ties the steering linkage to the wheel hub assembly, allowing for the transfer of motion to the wheel. | Signs of wear:
Rough or stuttered steering Play in steering-wheel Inner or outer tire edge wear |
BELTS, HOSES & FILTERS
V-Ribbed Serpentine Belt This belt transfers power from the crankshaft to the alternator, water pump, air conditioning compressor and power steering pump (if applicable). | Signs of wear: Slipping and/or squealing belt Dimming headlamps while driving Loss of battery charging |
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Cabin Air Filter Cabin air filters prevent a majority of airborne particles from entering the cabin. | Sign of wear: Decreased climate control (heating and A/C) airflow |
Timing Chain/Belt Your vehicle’s timing chain/belt synchronizes the engine’s camshaft and crankshaft. | Signs of wear:
Engine stops Engine backfires |
Air Conditioning Hose Refrigerant stored under high pressure is transferred from your vehicle’s evaporator in the engine compartment to the condenser in front of the radiator. | Sign of wear: A/C inoperative |
Heater Hose The heater hose within your vehicle routes the hot engine coolant to the heater core to heat the cabin. | Signs of wear: Coolant leak Cracking/hardening/brittleness of hose |
Radiator Hose The radiator hose moves coolant from the engine to the radiator to be cooled. | Signs of wear: Leaking Elevated engine temperature Coolant leak Cracking/hardening/brittleness of hose “Check Engine” light illuminates |
Engine Air Filters These filters prevent harmful debris from entering your engine. | Signs of wear:
Sluggish acceleration Decreased fuel efficiency |
Oil Filter Your vehicle’s oil filter cleanses engine oil to help reduce wear on the engine’s internal components. | Signs of wear:
Oil leaks Burning oil smell |
Automatic Transmission Filter This filter keeps certain abrasive particles in the transmission fluid from reaching the transmission’s internal components. | Signs of wear:
Late shifts Slipping in and out of gear |
In-Line Fuel Filter This filter was designed to trap fuel contaminants before they enter the engine’s fuel delivery system. | Signs of wear:
Lack of power Vehicle will not start Vehicle only runs in idle or low speeds |
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