The serpentine belt is the silent powerhouse of your car, driving vital engine components like the alternator and water pump.
Ever wondered what happens to a car when a serpentine belt breaks?
You’ll have to deal with a host of problems like a dead battery, overheating engine, and steering wheel issues.
But don’t worry!
We’ll explain what to expect if a serpentine belt breaks, the replacement process, and its costs, so you can be fully prepared.
This Article Contains:
- 7 Things That Happen When the Serpentine Belt Breaks
- How Long Can You Drive with a Broken Serpentine Belt?
- How to Replace a Broken Serpentine Belt
- How Much Does It Cost to Replace a Serpentine Belt?
- How Do You Prevent a Serpentine Belt From Breaking?
7 Things That Happen When the Serpentine Belt Breaks
A malfunctioning serpentine belt (drive belt or alternator belt) affects every car part, from the alternator to the engine.
Here’s what happens to a car when the serpentine belt breaks:
1. You’ll Hear a Squealing Noise
Notice a squealing noise from under the hood?
This happens when a serpentine belt slips on an idler pulley.
Additionally, if some engine components are misaligned, such as the crankshaft pulley or water pump, you’ll hear a chirping sound as the belt slides down on the pulley grooves.
2. Your Air Conditioner Stops Working
The serpentine belt drives the AC compressor, which circulates refrigerant to cool the cabin air.
If the belt breaks, the compressor will stop working, causing the system to blow hot air and leaving passengers uncomfortable.
3. The Engine Overheats While Driving
A broken serpentine or accessory belt stops the water pump from circulating coolant through the engine and radiator.
Without coolant flow, the engine’s heat can’t be dissipated. This results in engine overheating and can cause the temperature gauge to spike into the red zone, triggering the Check Engine Light.
4. You’ll Be Unable to Steer Easily
A bad drive belt can cause the power steering pump to fail, preventing it from circulating hydraulic fluid. This results in a loss of steering assistance and makes the steering wheel difficult to turn.
Since moving the steering wheel would require more force, driving, especially in heavy traffic, can be dangerous.
5. The Battery Dies Quickly
The alternator belt drives the alternator, which charges the battery and powers the vehicle’s electrical components.
When an old belt breaks and doesn’t turn the alternator, the battery can no longer recharge. This leads to a dead battery and a loss of power for essential functions like lights and ignition.
6. You’ll See Black Smoke From the Exhaust
A broken serpentine belt can cause voltage drops due to a malfunctioning alternator. This affects the engine sensors and results in inaccurate sensor data.
Based on the incorrect data, the ECU may instruct the fuel injectors to deliver excessive fuel, resulting in a rich air-fuel mixture. This results in incomplete combustion, and the unburnt fuel is expelled as black smoke from the exhaust.
Note: An overheating engine and failed emission control components, like an air filter, can also cause black smoke.
7. Your Dashboard Will Be Lit Up With Warning Lights
When a worn belt fails, the car’s sensors can identify various issues. For instance, the coolant temperature and power steering pressure sensors can detect voltage drops, increased engine temperature, and steering problems.
These sensors send signals to the ECU, triggering the Check Engine Light, battery light, and power steering warning lights.
Note: A broken timing belt can also cause similar problems. A timing belt synchronizes the crankshaft and camshaft rotations to ensure the engine’s valves open and close correctly. So, it’s best to consult a mechanic for the right diagnosis.
Curious how far a broken serpentine belt can take you?
How Long Can You Drive with a Broken Serpentine Belt?
It’s not recommended to drive in case of serpentine belt failure, as it can cause severe engine damage and costly repairs.
However, if you must get to a mechanic, the distance you can cover with a failing serpentine belt depends on several factors:
- Engine temperature: A car may be able to cover 3 to 5 miles before you notice signs of engine overheating, like steam coming from under the hood.
- Battery life: If the battery is fully charged, it’ll last around 30 minutes to an hour.
- Vehicle speed: Driving slowly through traffic extends your range by several miles, whereas highway speeds can reduce it.
So, instead of going to a repair shop, the safest bet is to call a mobile mechanic.
Next, let’s explore how a professional will deal with serpentine belt failure.
How to Replace a Broken Serpentine Belt
Replacing a broken serpentine belt is best left to a seasoned mechanic due to the technical expertise and tools required.
Here’s the process they follow for serpentine belt replacement:
Step 1: Disconnect the Battery
The mechanic will lift the hood and allow the engine to cool down. Then, they will disconnect the battery’s negative terminal.
Step 2: Locate the Belt
They will inspect the front of the engine to locate the fan belt (serpentine belt). The mechanic may refer to the owner’s manual to determine the belt’s path around the pulleys.
Step 3: Remove the Old Belt
Using a ratchet and socket, the mechanic will rotate the belt tensioner to reduce tension and release any part of the broken belt caught on the pulley. The tensioner is typically located near the front of the engine and connected to a small idler pulley.
Once the belt tension is reduced and the fan belt is free, the mechanic will slip it off one of the idler pulleys.
Step 4: Replace the Tensioner (If Required)
The mechanic will inspect the tensioner, idler pulley, and tensioner pulley for signs of wear and tear or irregular movement. If any parts are malfunctioning, they will repair or replace the parts.
Step 5: Install the New Belt
The mechanic will thread the new serpentine belt around all necessary parts, including the alternator, power steering pump, water pump, AC compressor, and crankshaft pulley.
They will then use a ratchet to turn the belt tensioner, allowing them to slip the new belt over the last pulley. For vehicles without an automatic belt tensioner, the mechanic will manually adjust the tension to the proper specification.
Step 6: Run a Test
Finally, the mechanic will start the engine and let it idle for a few minutes to ensure the serpentine belt doesn’t slip and rotates correctly.
But how much will this process cost you?
How Much Does It Cost to Replace a Serpentine Belt?
A serpentine belt replacement costs around $90 to $250. Let’s break it down:
- Cost of part: $15 to $80
- Labor charges: $75 to $170
The replacement process usually takes less than an hour. However, if other related parts, like the alternator or water pump, need replacing, it can take an additional 3-5 hours.
To avoid these costly repairs, we’ll share some preventive maintenance tips to extend the belt’s life.
How Do You Prevent a Serpentine Belt From Breaking?
Here are some car care tips to prevent the drive belt from failing prematurely:
- Regularly inspect the belt and related engine accessories for any signs of wear.
- Ensure the belt tension is properly adjusted. For a modern car, ask your mechanic to verify if the automatic belt tensioner is functioning correctly during regular maintenance.
- Avoid driving through puddles or floodwaters to prevent water from splashing onto the drive belt.
- Keep the belt and pulleys free of oil and debris, as it can cause slipping and wear.
Replace Your Broken Serpentine Belt with AutoNation Mobile Service
Driving to a mechanic with a failing serpentine belt can be difficult and can even lead to more expensive repairs, like severe engine damage.
Fortunately, you can avoid this risky drive by having AutoNation Mobile Service professionals fix the problem right from your driveway.
We’re a mobile auto repair and maintenance solution that offers easy online bookings and a 12-month | 12,000-mile warranty on every auto service.
Contact us to handle all your car repair and preventive maintenance needs.