Modern combustion engines require timing belts in order to maintain the precision timing of the engine. If you have a car that runs on gasoline or diesel then there's a good chance your engine has either a timing belt or a timing chain installed. While timing chains are made of a much more durable metal than the rubber composite material used to make timing belts, not every car uses a chain. If you are still using a belt, then replacing that timing belt is part of the routine maintenance that you need to keep your car running smoothly. Your manufacturer will tell you in your owner's manual exactly when you need to replace your timing belt, but there are some signs and symptoms you could be on the lookout for to let you know when something's going wrong.
What Is a Timing Belt and What Does a Timing Belt Do?
The timing belt in your car's engine is a rubber belt with teeth on the inside that connects your camshaft to your crankshaft. When you first start your car, the crankshaft will start to rotate. This is what causes the pistons to rise and fall in the cylinders of your engine. As the crankshaft rotates it causes the camshaft to rotate with it which in turn opens and closes the valves at the top of your cylinders.
The pistons will rise through the cylinders and through the open valves. The fuel and air mixture are injected into the combustion chamber where your spark plug is able to ignite it causing a small explosion that forces the piston back down. This reaction will occur again and again, hundreds of times per minute in every cylinder of your engine. That's what provides the power to keep your car moving. However, it is the timing belt itself that ensures everything happens exactly what it needs to. if your timing belt isn't working the way it's supposed to, either because the teeth are worn off or it's become loose or broken then timing of your engine will suffer as a result and your combustion reaction will not occur when it needs to. This could result in things like engine stalls and misfires.
If your timing belt were to break your engine would cease functioning entirely. The camshaft would stop rotating which would prevent the valves from opening. However, your crankshaft will continue to rotate causing the pistons to crash into the closed valves. This can cause extensive damage to the pistons, the valves, and the cylinder heads. The damage caused by a broken timing belt could be extremely severe and end up costing you upwards of $4,000 to $5,000 or more. It's possible you'll need a total engine replacement to fix this.
What is the Average Cost to Replace a Timing Belt?
The cost of replacing a timing belt very much depends on a number of factors. The make and model of your vehicle has to be taken into consideration as well as where you take your car to get the timing belt replaced. If you head to a dealer, they're going to charge you more than a mechanic will, and the price range for one mechanic to another can vary extensively. Because of that, the average cost of replacing the timing belt is across a very large range. You can expect to pay anywhere from $300 at the low end to well over $1,000 at the high end of the scale.
If you want to just get the part, you can head to a site like AutoZone and you'll see that timing belts cost anywhere from as little as $20 to as much as $400. The rest of the cost is made up of labour fees the mechanic is going to charge you. Replacing a timing belt is a very labor-intensive repair job and will probably take your mechanic a couple of hours to get done. They have to get deep into your engine bay to replace this part.
It's possible that you could replace your timing belt on your own at home, but it's not recommended unless you have a lot of experience doing engine repairs already. This is not a beginner repair job by any means so if you're not comfortable working under the hood of your car then leave this one to the professionals.
How Do You Know When to Replace a Timing Belt?
If your car has a timing belt installed in the engine then your owner's manual is going to tell you exactly when it needs to be replaced. The lifespan of a timing belt can vary greatly from one model to another. Something like a Toyota Camry will require you to replace your timing belt every 60,000 miles. However, a Honda Civic might not need a timing belt replacement for 110,000 miles depending on the year. With such a great discrepancy between those two numbers, you can't really rely on the averages that you'll find on the internet about when to change the timing belt. For the most part it's between 60,000 miles and 90,000 miles, but obviously if your timing belt can last 110,000 miles switching it at 60,000 miles would be unnecessary. Likewise, if it needs to be done at 60,000 miles you definitely don't want to wait another 50,000 miles and take any chances.
Signs and Symptoms of a Bad, Loose, or Slipped Timing Belt
When your timing belt begins to fail on you there are a handful of signs and symptoms you can be on the lookout for to let you know you have a problem. The moment you start experiencing any of these you should get yourself to a mechanic as soon as you can so they can inspect your timing belt and see if it needs to be replaced or not.
Unusual Ticking Sounds
When your timing belt begins to fail it will start producing a fast-paced ticking sound, which is the most obvious sign that you have a problem with your timing belt. Normally when a belt in your engine goes bad it produces a squealing sound, this is what happens when your serpentine belt fails. It is possible that you will hear some squealing from your timing belt when it fails as well, but it's very rare and we'll only happen intermittently. The ticking sound will be a constant noise, sounding a bit like a fast-spinning roulette wheel. It's caused by the teeth on the inside of the belt wearing down and clicking as they rotate between your camshaft in your crankshaft.
When your timing belt is slipping off the gears or too loose to maintain precise timing, you're going to start experiencing engine misfires as a result. This occurs when the combustion reaction is not able to take place when it's supposed to, resulting in your engine firing too late or not at all. This is going to cause severe performance problems with your engine and can potentially lead to damage and engine stalls as well.
When your timing belt isn't able to maintain the proper tension between your camshaft and your crankshaft, maybe as a result of the teeth getting stuck in the gears, it can cause your engine to lurch and surge unpredictably. This results in rough idling when your car seems to shake for no reason whatsoever. Over a long enough time, this can cause some serious engine damage.
Oil Pressure Problems
When the teeth on the inside of your timing belt begin to break off, they will collect in the oil pan beneath your engine. Eventually they will clog in the pan and prevent your oil from filtering back through your engine properly. This drop in oil pressure can end up causing additional problems like your engine overheating and lead to it seizing up or experiencing more severe damages. An overheated engine can end up costing you quite a bit of money to repair.
How Long Can You Drive with a Bad Timing Belt?
If you know your timing belt is showing signs that it's wearing out or coming loose, there is no safe amount of time that you can continue to drive with it. When the timing belt breaks it's not like your engine slowly overheating because you need to have the oil changed. You're not going to get that moment when you realize something's wrong so you can safely pull over to the side of the road and call a mechanic or a tow truck to fix it for you.
When your timing belt fails it happens instantly. The moment your timing belt breaks your engine stops working. You have no reaction time to deal with this. The pistons will crash into the close valves of your engine and likely cause your engine to immediately seize up. This will cause your entire car to stall and could potentially cause an accident especially if it happens while you're driving on the highway. So, if you know you have a problem with your timing belt, then you need to get it addressed as soon as you can before it becomes a safety risk, and also a much more expensive repair job.