Toyota’s have a wide range of discrepancies when it comes to timing belts and timing chains and this can be the difference between expensive maintenance and no maintenance whatsoever. Ensuring that you have accurate information about your model can save you from costly repairs and even the junkyard.
Do Toyota Timing Chains Need To Be Replaced?
Replacing the timing chain is one of the most important maintenance steps your Toyota will need, but timing chains have no set schedule for replacement. Timing chains may need to be replaced when the chain loosens, which may occur up to around the 250,000 mile mark. Timing belts typically require maintenance at about 60k to 100k miles, depending on the specific model and year.
Because there is a night and day difference between vehicles with interference and noninterference engines and those with timing belts and timing chains, it is important for Toyota owners to fully understand the matter.
An $80 strip of rubber can mean the difference between shelling out for a new vehicle and keeping your current ride going for a lifetime. For your convenience, we have fully explained the matter in detail below.
When Is Toyota Timing Maintenance Required?
If your timing belt or timing chain were to fail, it would immediately cause catastrophic engine damage. Toyota’s primarily use interference engines that must be run in perfect synchronicity to prevent the valves from smashing into the pistons.
If the valves smash into the pistons, you can severely damage your engine, which may require a complete engine rebuild or replacement.
Knowing the specific maintenance schedule for your timing belt is one of the most important aspects of ownership. Knowing whether your engine is an interference or noninterference type is also critical. Many shops have steered Toyota owners astray by recommending that they junk a perfectly good vehicle with a timing belt issue.
The reality is that engines are difficult to time and hard to repair when they need timing belt replacements done. The job requires numerous hours of difficult disassembly, special tools to set the timing, and clear instructions to ensure that no engine damage occurs. A lot of shops would rather not get involved when they can bolt on a new exhaust system and make even more money with zero risks.
The Difference Between Timing Chains and Timing Belts
A timing belt is a thin rubber belt with notched teeth on it that lock into timing gears along the side of the engine. The timing belt is often hidden beneath the serpentine belt assembly within a metal encasement.
This protects the belt from the elements and contamination. But being that the timing belts are made out of vulcanized rubber, they can deteriorate in just five years and break under stress.
Timing chains look a lot like a bicycle chain. They are also hidden in a metal encasement and connect gears together between the upper half of the engine and the lower half. These gears have to be perfectly timed to allow for efficient compression and combustion.
The Difference Between Interference and Noninterference Engines
In an interference engine, the moving parts of each half share the same middle space and simply change positions every split-second to prevent a collision.
A noninterference engine will completely turn a full revolution even if it is completely out of time without causing any damage.
The lower half of the engine is called the engine block. This is where the pistons are housed within sturdy cylinder walls. The pistons move up and down on a crankshaft encased within a set of smooth bearings that are lubricated with oil. The ignition and combustion of the ideal fuel and air mixture occurs in these cylinders.
The upper half of the engine is called the head. The head contains hydraulic or spring pressured mechanisms called lifters. These lifters actuate the valve train and open a port for fresh air to enter before the next ignition.
In simpler terms, the head allows the engine to breathe. The block simply allows the pistons to travel up and down and builds up the pressure to move each piston as the fuel-air mixture is ignited by the spark plugs.
When Exactly Do I Change My Timing Belt or Chain?
Rubber timing belts came about during an oil crisis when manufacturers were looking for ways to economize the costs of building a vehicle. Timing belts require maintenance at about 60k to 100k miles and should be checked every five years. You can use this chart to determine whether your Toyota model uses a timing belt or chain.
The timing chains are sturdy and only require maintenance if they’ve become loose with age and excessive wear. Normally, a timing chain can last for a quarter-million miles or longer without any problems.
There is no recommended service interval for a timing chain because they are designed to last the lifetime of the vehicle. If you hear rattling or your engine is suffering performance problems, you may remove the cover and check the timing chain for excessive play, damage, or wear.
Here is a list of interference and noninterference engines. You will probably have to do a little more research to find out what specific engine you have in your vehicle. And you still might want to double-check the next time you have service done.
What Are the Signs and Symptoms of a Bad Timing Chain or Belt?
The obvious symptoms of your engine being off basic time are hard chugging, rough idle, misfires, lack of power, poor fuel economy, and possibly whirling or whining noises coming from the engine bay. A lot of times, a timing belt will show no symptoms and will simply snap from dry rot or stress as it ages.
This is why interval replacement is so important. While a visual check can be done by simply removing the cover, you’d might as well just replace it with all the labor involved in getting that far. A visual inspection may reveal missing teeth, worn teeth, fraying, small cracks in the rubber, or that the belt is brittle or loose. In many cases, the tensioner itself may be the problem.
It is recommended that the timing belt, pullies, tensioner, water pump, and thermostat all be replaced at the same time when a timing repair is done. Because it is labor-intensive, the costs of labor can be split in half when you focus on combining the work into one job.
If the belt is frayed, this may reveal that the pulley gears are bent or that the belt is walking due to a lack of tension. The timing chains usually begin to rattle when they are worn. In either case, if the belt is stretched or the chain is loose, an engine warning light may indicate a problem by the presence of misfires.
A timing chain or belt only needs to be off by as little as half a tooth to cause serious running problems. But there are more parts in the system than the belt or chain that can cause problems.
Additional Mechanisms that Affect Engine Timing
In a lot of vehicles, they have a type of variable cam timing. Tuners have long recognized that minute adjustments to the cam timing can change how the engine performs. Advance it this many degrees to increase the power at higher RPMs. Retard the timing slightly, and the low-end power seems to shine through.
Many of the engines that feature variable cam timing are powered by hydraulic systems that retard or advance the timing with changes in oil pressure. While these items can fail and cause similar problems to a stretched timing belt, they are rarely the problem. Always rule out a problem with the basic timing before considering other factors.
Misfires and loss of power can also occur from numerous other problems. A clogged catalytic converter, fouled spark plugs, broken ignition wires, bad ignition timing, a clogged or dead injector, vacuum leaks, and a weak battery, are just a few of the other problems that can cause rough running.
If you service your Toyota regularly and stay on top of all your maintenance, it will be easier to pinpoint particular problems as they pop up. Most vehicles deteriorate and become unrepairable when the owner lapses on maintenance and the total sum of issues reduce the vehicle to junk. All the systems of a vehicle are interconnected. Failing to correct even one issue can lead to a chain reaction.
Replacing your timing belt is the most important aspect of preventative maintenance. Never lapse on maintenance or trust the word of a shop that your engine is dead without doing the appropriate research. And even if your timing belt does break, you can usually find a used head and have the vehicle repaired for under $2,000. It may require some downtime but is cheaper than buying a brand-new vehicle.