Don’t ignore a worn timing belt! This crucial engine component is under extreme stress, so manufacturers recommend regular replacement. Worn belts can snap, leading to catastrophic engine failure costing thousands in repairs.
Learn to recognize common symptoms of a bad timing belt and proactively replace it before major damage occurs. While timing belt replacement is anything but cheap, it can get a whole lot more expensive if you simply keep putting it off.
Symptoms of a Bad Timing Belt
If you have a bad or worn out timing belt, the following are symptoms that may occur. Once you experience one or more of these symptoms, have a certified auto technician or mechanic inspect the timing belt and then replace it if necessary.
A timing belt that is worn or damaged will typically show some signs that everything isn’t all right. If you experience one or more of the symptoms below, make it a priority to have a trusted service center inspect and replace the belt if necessary.
#1. Rough Engine Idle.
Rough idling is often one of the first noticeable symptoms of a timing belt issue. When your engine is idling, it should run smoothly with minimal vibration. But with a worn or damaged timing belt, that’s not the case.
When the teeth on the belt are worn or broken, it can cause the belt to slip, leading to the engine’s timing being off. This misalignment often results in a rough idle because the engine’s valves and pistons are not operating in sync.
#2. Misfire of the Engine.
A worn timing belt can slip, disrupting the precise synchronization between the camshaft and crankshaft. This misalignment can cause cylinders to open and close at incorrect intervals, resulting in engine misfires.
You may experience irregular engine performance, hesitation during acceleration, or a noticeable loss of power.
#3. Excessive Exhaust Smoke.
When the timing belt is not functioning properly, it can cause the engine’s timing to be off, leading to incomplete combustion. This incomplete combustion can result in excessive smoke from the exhaust.
The color of the smoke can vary depending on the specific issue: white smoke may indicate coolant entering the combustion chamber, while blue or black smoke could suggest oil burning due to improper valve timing.
#4. Oil Pressure Drop.
A failing timing belt can cause camshaft gear damage, potentially releasing metal fragments into the oil pan. These debris can clog oil passages, leading to a sudden drop in oil pressure throughout the engine.
Low oil pressure can result in inadequate lubrication, increased friction, and potential engine failure.
If you notice oil pressure warning lights or unusual engine noises, immediate inspection is necessary no matter if it ends up being a timing belt issue or something completely different.
#5. Broken Pistons or Valves.
The most severe consequence of a broken timing belt is potential piston and valve damage. When the belt snaps, the crankshaft and camshaft lose synchronization, allowing pistons to collide with open valves if your vehicle has an interference engine.
This can result in bent valves, damaged pistons, or even more extensive engine damage. If you experience sudden engine failure or loud noises, stop immediately to minimize potential damage.
#6. Ticking or Clicking Noise.
A distinctive ticking or clicking noise coming from the engine bay is another sign of a possible timing belt problem. This sound, typically most noticeable when the engine is idling, occurs as the worn belt’s teeth struggle to maintain proper grip on the pulleys.
As the belt’s condition worsens, its ability to smoothly transfer motion between the crankshaft and camshaft diminishes, resulting in this audible symptom. The noise may start intermittently and gradually become more persistent as the belt’s condition gets worse.
While other engine components can produce similar sounds, a rhythmic ticking that increases with engine speed often points to timing belt issues.
Timing Belt Replacement Cost
The replacement cost of a timing belt is dependent on the number of labor hours that were spent on the replacement job. After all, with some cars, it is a lot harder to gain access to some of the components like the timing belt.
For economy cars with small engines, the labor should be cheaper for this because they are easier to disassemble. But if you’re driving an SUV or a truck, they have bigger engines which mean you’ll be paying more money.
The average cost to replace a timing belt will be anywhere from $300 to $500 in total (more for larger cars, trucks, and SUVs). The price of a timing belt itself is usually less than $50 but the majority of a timing belt job is spent on labor.
The cost of the labor will be anywhere from $250 to $450 or more. There will likely be taxes and fees added onto these prices too.
NOTE: It’s often recommended to replace the water pump at the same time while in there since it’s in the same area. It may cost a bit more for a new water pump but you’ll save a lot of money on labor costs if you were to do it later on.
When Should a Timing Belt Be Replaced?
A timing belt is one of those things that’s critical to replace according to the auto manufacturer’s schedule. Most often this will be between every 75,000 and 100,000 miles. Check your owner’s manual for the exact schedule for your vehicle.
Replacing your timing belt is not one of those things you can just put off indefinitely. Eventually, the belt will break and you may have thousands of dollars in engine damage. It’s simply not worth the risk.
Timing Belt Replacement Process
Unless you have a lot of auto repair experience, a timing belt replacement is not an easy DIY job and should be handled by a professional.
The mechanic needs to gain entry to the timing cover of the engine by removing various accessories. After removing the cover, the mechanic will analyze the timing belt and its pulleys to see what is in need of replacement.
At this point, he will begin to remove the timing belt and replace it with a new one. They will likely replace the pulleys, tensioners, and water pump if they feel it is important to do so.
Once all the new parts are in, he will put the timing cover back on and any other parts that were removed. Now that it is all put back together, it can be tested with the start of the engine.
Is the engine running like it should? Is the timing of the engine good? If the answer to both of these is yes, then you are in good shape. Pay the mechanic and then you are done.
How a Timing Belt Works
Unless you drive an EV, all modern vehicles have either timing belt or timing chain. For more info about timing chains.
A timing belt is responsible for synchronizing the rotation of the crankshaft and camshaft(s).
This precise timing makes sure that the engine’s valves open and close at the correct intervals relative to the position of the pistons, allowing for proper intake of air and fuel, and exhaust of combustion gases.
The belt is typically made of reinforced rubber with teeth that mesh with sprockets on the crankshaft and camshaft.
As the crankshaft rotates, driven by the power of combustion, it turns the timing belt, which in turn rotates the camshaft(s) at exactly half the speed of the crankshaft.
Engines are classified as either interference or non-interference types, and an engine’s type has a major effect on timing belt failure:
- In interference engines, the pistons and valves occupy the same space in the cylinder at different times. If the timing belt breaks, the piston can collide with open valves, which can cause severe (and expensive) engine damage.
- Non-interference engines have adequate clearance between pistons and valves, even if the timing is off. While a broken timing belt will still cause the engine to stop running, it’s less likely to result in catastrophic damage.