Car engine timing chain or belt
One of the most frequently asked questions we get is whether a given car engine has a chain or a belt? So here's a tool to help you determine which, as well as an explanation of the basic differences.
Does car engine have a chain or a belt?
In a car engine, a timing chain or belt does the same function - it rotates the camshaft, while the camshaft opens and closes the valves to keep the engine running. The chain is made of metal links, while the belts are made of durable rubber constructions. The chain is located inside the engine, while the belt is visible from the outside and therefore easier (and cheaper) to replace.
Should the chain be changed less frequently than the belt? How much does it cost to replace an engine chain and timing belt?
It is commonly believed that the engine chain should be changed less often than the belt, and this is generally true - there are engines for which the manufacturer has not specified a chain change interval at all, claiming that the chain will last as long as the engine itself. But there are exceptions - there are engines of more unsuccessful designs that tend to stretch the chain and need replacing after 50-60 thousand kilometres, while belts with replacement intervals of 100 thousand km or more are not uncommon. As for the replacement interval, it should be remembered that the timing belt is affected by both age (the belt should not be used for more than 4-5 years) and operating conditions (salt, sand, engine fluids, etc. shorten the life of the belt), while the chain is virtually unaffected by these conditions. In most cases, the cost of replacing the timing belt is much lower than the cost of replacing the chain. The cost of replacing a chain can often reach €1000 or more depending on the engine design.
The timing belt replace cost is usually no more than a few hundred euros, but this can increase with the additional parts that need to be replaced with the timing belt.
How does a chain engine differ from a timing belt engine?
In general, chain motors are considered louder and more vibration-generating, but this depends on the particular motor. Chains are more common on larger displacement engines, belts are more prevalent on small and economical engines. In theory, chain motors have slightly higher fuel consumption because the chain is heavier than the belt.
What happens if the engine chain or timing belt is not being replaced?
If the belt and chain are not replaced in time, sooner or later they will break and the consequences can often be dramatic and very expensive - an engine overhaul.
There are some engines and successful cases where a chain or belt breaks and all you end up with is the replacement of the broken part, but the most common situation is that pistons meet valves, valves are bent and other serious damage is done to the engine. The outcome is either an engine repair costing thousands or a complete engine replacement. This is why the timing belt replacement interval should be monitored with particular care and, when buying a used car, if you are not sure when the timing belt has been changed, it is better to carry out a preventive replacement. The chain is safer in this respect and usually "signals" in advance (by unusual sounds, vibrations, etc.) the need for a change. There are engines where, with regular maintenance and quality oil, the chain can last up to twice as long as the manufacturer's specification - with regular attention to the condition of the chain, of course. The necessity to change timing chain is determined by the wear of the chain tensioners and the condition of the chain itself (wear and stretch). For most engines, the engine cover must be removed to check the condition of the chain. However, there are engines (e.g. certain VAG (Wolksvagen) engines) for which a special inspection window is provided to check the condition of the chain tensioners and the engine does not need to be opened.