8 parts covered
The heart of your vehicle. Engine components are critical to performance, fuel economy, and emissions. Failures can range from minor inconveniences to catastrophic damage requiring full engine replacement.
Spark plugs ignite the air-fuel mixture in your engine's cylinders, creating the controlled explosions that power your car. They're one of the most commonly replaced engine components and a key part of routine maintenance.
Total Cost
$100 – $350
Lifespan
30,000 – 100,000 miles depending on type
DIY Difficulty
If It Fails
Ignition coils transform your car's low-voltage battery power into the high-voltage spark needed to ignite fuel. Modern cars use one coil per cylinder (coil-on-plug design), so a single failure affects only one cylinder.
Total Cost
$150 – $400
Lifespan
80,000 – 120,000 miles
DIY Difficulty
If It Fails
The timing belt or chain synchronizes the rotation of the crankshaft and camshaft, ensuring that engine valves open and close at precisely the right moments during the combustion cycle. Belts require periodic replacement; chains are designed to last the life of the engine but don't always.
Total Cost
$500 – $2,000
Lifespan
60,000 – 100,000 miles
DIY Difficulty
If It Fails
The water pump circulates coolant through the engine, radiator, and heater core. It's driven by the timing belt, timing chain, or serpentine belt depending on the engine design. When it fails, your engine can overheat within minutes.
Total Cost
$300 – $1,000
Lifespan
60,000 – 100,000 miles
DIY Difficulty
If It Fails
The thermostat is a valve that regulates engine coolant flow. It stays closed when the engine is cold (allowing it to warm up quickly) and opens when the engine reaches operating temperature (allowing coolant to flow through the radiator).
Total Cost
$150 – $400
Lifespan
80,000 – 150,000 miles
DIY Difficulty
If It Fails
The head gasket seals the joint between the engine block and cylinder head. It's one of the most critical gaskets in your engine, sealing combustion gases, coolant passages, and oil passages simultaneously. Head gasket failure is one of the most expensive common repairs.
Total Cost
$1,000 – $3,000
Lifespan
150,000+ miles
DIY Difficulty
If It Fails
The oil filter removes contaminants from engine oil as it circulates through the engine. It's replaced with every oil change and is one of the cheapest yet most important engine components.
Total Cost
$5 – $20 (part only; included in oil change cost)
Lifespan
3,000 – 10,000 miles
DIY Difficulty
If It Fails
The engine air filter prevents dust, debris, insects, and other contaminants from entering the engine's intake system. A clean air filter ensures optimal airflow for efficient combustion.
Total Cost
$15 – $50
Lifespan
15,000 – 30,000 miles
DIY Difficulty
If It Fails