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The timing belt is so crucial to your engine’s operation that its failure is often catastrophic – meaning, not only does your vehicle suddenly not run, the internal engine is likely damaged. It is one of those parts that as much as the replacement is painful as routine maintenance, choosing not to perform this maintenance will absolutely lead to a catastrophic failure, and an even bigger bill.

Below is what you need to know about a timing belt, its function, and how to make sure you stay on top of its replacement.

What a Timing Belt Does

If you have heard of the term “Timing Chain” before, both a timing belt and chain perform the same duty. Their job is to keep the mechanical timing of the engine – the intake and exhaust valves opening and closing at the exact precise time needed. Today’s engines are composed of multiple valves per cylinder, sometimes as many as 5 – and doing this properly requires exact precision between the moving pistons and the opening of the valves.

The timing belt (or chain) is located toward the front of the motor beneath the timing cover. The belt is made with high-quality rubber and reinforced with nylon chords. This belt is under precise tension, and as the engine’s crank turns, it then turns the camshafts (and many times, the water pump) to keep everything in perfect timing.

If a timing belt is not set up properly, “jumps time”, or worse yet – breaks, that functioning will cause the valves to be open at the wrong time. Because most engines are made with zero clearance between the piston top and the valves, this then causes in many cases the piston to collide with one or more valves in the cylinder head, causing bent valves and major damage.

When to Replace Your Timing Belt

As stated before, timing belts are composed of rubber, no different than a regular drive serpentine belt. Over years and constant heat cycling, the rubber begins to degrade, to the point where the belt finally fails. In most cases, a faulty timing belt will provide no warning of an impending break. You will be driving along, when suddenly the car dies. 

Because of severity of a belt breaking, every vehicle equipped with a timing belt will have a manufacturers recommendation on when to change the timing belt. These intervals are usually somewhere between 70,000 miles and 90,000. You can find recommendations specific to your vehicle by checking with the owner’s manual that came with your car or researching online.

Another thing to consider is that miles are only a general indicator, older, low mileage vehicles should always be considered for a timing belt change because usage is not the only thing that degrades the rubber – time will as well. For example, you own a 2016 vehicle with 60,000 miles on it, and its timing belt recommendation is 70,000 miles. At this point, it is time to start planning your timing belt service. In contrast, you own a 2001 vehicle that has been minimally driven, only has 40,000 miles, but there is no evidence of a timing belt ever being replaced. Because this belt is over 20 years old, it is prime for replacement. Either way, this is one maintenance item you absolutely want to plan for, and do not want to neglect.

Can You Tell When the Timing Belt is Going Bad?

Unfortunately, timing belts rarely give any warning of impending doom. While there are other things that can speed up a timing belt’s decay, like oil or antifreeze leaking into the timing belt area (and often seen as an oil leak or water pump leak), in most cases, the belt is simply old, brittle, and breaks.

Most timing belt covers are plastic and have one or several inspection plugs, or ports, where you can quickly remove and look at a small portion of the timing belt. One of the first things to inspect is cracks on the belt. Rubber as you know will crack and chip as it gets older, and any evidence of cracks on the belt should immediately raise a red flag for a belt change.

Another thing to consider is service records. Whenever buying a used car that is equipped with a timing belt, always ask about timing belt service. When was the last time it was performed, if ever? Does the owner have documentation in the form of receipts or invoice? Has the vehicle been to the dealer? Keep in mind, calling the dealer and asking for service records may lead to clues on when the belt was last changed, or if it was at all. Finally, when in doubt, change the belt!

How Much Does It Cost to Replace a Timing Belt

A timing belt service is more than just the belt itself. While traditionally, everyone thinks of this change as “just the belt,” it is not. A timing belt is tensioned and held in the proper track by a series of tensioners and idler pulleys, all of which have bearings and the ability to fail. Likewise, many vehicles have a water pump that is driven by the timing belt. In these cases, it makes complete sense to change the water pump with a new unit at the same time, since the labor to expose the pump is being completed anyway.

There is nothing worse than paying for a timing belt service, declining the water pump replacement for an additional $100.00, only to find out 6 months later that the water pump is leaking, and now everything must be replaced again.

In most cases, a timing belt kit will consist of the belt itself, 2-3 idler pulleys, and a tensioner. When the job is done, all these components will be changed out. In most cases, a timing belt kit will run between $100.00-350.00.

Labor on most timing belts is between 3-5 hours, putting your total cost between $400.00-1,000.00. Remember, do not opt for a “just the belt” replacement. While the cost is cheaper, the chances of further failure increase significantly. If the water pump is being done at the same time, the labor should be minimal, and less than 1 hour, as the work to expose the water pump and remove the timing belt is being done anyway.

If you decide to do the job yourself, make sure you follow each step of removal and reassembly perfectly, and research as much as possible on the job. Many timing belt jobs require the camshafts to be held in place by a special tool – do not let this scare you. While these tools are readily available, many of them are vehicle specific, so there can be a multitude of them. Many other tricks are shown online on how to keep the camshafts properly in place when installing the new belt, and many more do not require any tools for this at all.

Remember that once the new belt is in place and properly tensioned, always rotate the engine slowly by hand, checking and double-checking the belt alignment and make sure everything looks proper. If any resistance is encountered, stop! Recheck the alignment.

Remember, if your timing belt breaks, the damage is much, much worse. At this point, the cylinder head must be removed, valves replaced, or new remanufactured heads installed. This takes that timing belt job from $400.00-1,000.00 and just raised it to $3,000.00-5,000.00. In many cases, repairing a timing belt breakage is so expensive it is more than the value of the vehicle.

What to Do Next

If you suspect your vehicle is up for a new timing belt, come see the folks at AutoZone for all the parts, tools and advice you’ll need. If you need additional help with the job, check out our list of Preferred Shops in your area that can help you get the job done quickly!

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