This is one of the most common questions with a car nowadays. It is no longer a question of comparing a timing belt with a timing chain, but to understand the quality of the engines on both sides. Why is that? The short explanation is that the technology has advanced and modern engines work better with one drive system or the other. The issues can come from the engine design along with lack maintenance, not from the chain or the belt itself.
The question of "which is better?" can never be answered. Both systems are permanently being further developed and updated. Mechanically, there is no difference between a timing chain and a timing belt. Both perform the same action and are attached to the same parts of your vehicle. The difference is in the material and location within the automobile. A timing belt is made of reinforced rubber and is housed outside the engine casing. A timing chain is made of metal links and housed within the engine unit.
While timing belts have been steadily giving way to chains due to their longer service life, belt manufacturers have made strides to improve their belt life to more than 120,000 miles, in some cases. Even though belts will not last as long as a chain, they are quieter, create less friction, and are easier to service.
In most cases, if the engine is properly maintained, service interval would be the main advantage to a chain over a belt. The chain is also, for lack of a better word, more durable. Thinking back to the days of timing belts, if the front crank seal leaked on an engine to the point of coating the belt with oil, you would most likely find the belt nearly shredded when inspecting it due to the oil saturation. On a chain-driven timing set, you simply change the crank seal, clean up the mess from the oil leak and move on.
The easiest way to know if your engine has a chain or a belt system is to take a quick look at the engine. If it has plastic covers on the front, it probably runs a timing belt because the timing belt runs dry and does not need more protection. However, if it has a sealed metal cover (to prevent the engine oil from leaking out) then it is usually a chain system.
Unfortunately, in most cases, there are no obvious signs the timing belt is near its end of life; it can break, loose teeth or jump its timing any time. There is no visual timing belt inspection required. Timing belts have a scheduled replacement life specified by your vehicle manufacturer (check your vehicle owners manual). The recommended timing belt replacement interval is usually 60,000 to 105,000 miles depending on the vehicle and engine. In comparison, the replacement intervals for modern timing belt engines have been greatly extended (to 150,000 – 200,000 miles) due to further development and new materials.
Originally, or rather back when engines were built with sturdy chains, these chains lasted forever. In today's downsized compact engines, things look different. The chains do not have a replacement interval specified by the manufacturer, but they often have to be replaced quite early because the chain has elongated (sometimes between 80,000 and 130,000 miles).
As a general rule, if an engine has a timing chain and the oil was changed on a regular basis, the timing chain should last the lifetime of the engine, however, service technicians are seeing timing chains fail much sooner. For an internal combustion engine to operate properly, it must exhibit exact, mechanical engine timing. More specifically, the crankshafts and camshafts must rotate in concert with one another. Timing chains are the critical link between the crankshaft and camshaft.
Tensioners make sure the chain is tightly wound to the gears. If the tensioner fails and the chain becomes loose, the timing of the engine is thrown off. And, if the timing chain becomes loose, you can get ready for serious and costly problems. If the timing chain jumps while you are driving the car, the valves could be damaged from contact with the pistons and potentially ruin the engine.
The very nature of a chain unit means that failure often means total calamity. If the chain breaks, the part will no longer do its job and, unfortunately, the car will no longer be able to run.
But, issues don’t always mean complete failure of the part. The chain can show signs of wear and damage before it gives way completely. Look out for the following warning signs that your timing chain is about to reach the end of its service life:
Unlike a vehicle equipped with a timing belt, the timing chain is not considered a regular maintenance item and only needs to be replaced when symptoms are present. Should the timing chain need to be replaced, replacing all components related to the timing chain such as guides, tensioners, sprockets, variable valve timing actuators or motors that may be out of spec, and balance shaft chains if equipped at the same is the recommended procedure. The labor cost to replace these parts is usually high due to the amount of disassembly and assembly required to service these parts. Replacing them at the same time as the timing chain can prevent future breakdowns.
As soon as you suspect that you need a timing belt or timing chain replacement in the Mentor, OH area, we invite you to bring your vehicle into the experts here at 5 Star Auto Care. You can trust that our ASE certified technicians will take excellent care of your car, regardless of the make and model.