BMW 325i Timing Belt Or Chain? – Get Over Your Confusion

The BMW 325i models built between 1987 and 1993 have timing belts, and those made from 1994 to 2012 have timing chains. The timing belt and timing chain are responsible for synchronizing the crankshaft and camshaft. Despite their similar purpose, both have their own advantages and disadvantages.

Do you have a BMW 325i, but you never encountered whether it has a timing belt or timing chain? Does your mechanic mention it for the first time? No worries.

So, today, I will explain your query on BMW 325i Timing Belt Or Chain?

Let’s discuss the matter in detail, along with the advantages and disadvantages.

Does The BMW 325i Have a Timing Belt Or Chain?

The BMW 325i models that are produced between the years 1987 and 1993 come with timing belts. Those manufactured between 1994 and 2012 have timing chains. All the models come with an interference engine and a lifetime replacement interval.

Model YearsTiming Belt SystemGenuine OEM Part NumberInterchangeable Part OEM NumberCost
Timing Chain11318648732(N52)11318618317 (N53)1131758408411317516074$85-$130
Timing Chain1131143217711311722753 11311730188$70-$95
Timing Chain
Timing Belt11311713361113117110811131127238411311286168$56.88

What are the Types of Timing Chains BMW 325i Use?

The BMW325i models from 1994 to 2012 are equipped with roller simplex metal timing chains. A roller simplex timing chain is a type of timing chain that uses small rollers or bearings to reduce friction and wear between the chain links.

Simplex timing chains have a single row of links and are commonly used in automotive engines. They offer a good balance of strength, durability, and smooth operation. Also, they generally last longer and are relatively easy to maintain.

What Other Types Of Timing Chains are Available?

Three main types of timing chains are used in automobiles: duplex timing chains, triplex timing chains, and silent timing chains. Let’s discuss them in detail.

Duplex Timing Chains: A duplex timing chain has two rows of links that are connected together by a series of crossbars. Duplex timing chains are more durable and stronger than simplex timing chains (which have a single row of links). They are often used in high-stress applications such as heavy-duty engines.

Triplex Timing Chains: A triplex timing chain is similar to a duplex timing chain but has three rows of links instead of two. Triplex timing chains are even stronger and more durable than duplex timing chains. However, they are also more complex and may be more prone to stretch or failure if not properly maintained.

Silent Timing Chains: Silent timing chains are similar to roller timing chains but have additional features that make them quieter and smoother. Silent timing chains are often used in high-end engines where noise and vibration are a concern.


There are four main types of timing chains: simplex, duplex, triplex, and silent. Duplex timing chains are more durable than simplex timing chains, and triplex timing chains are more complex. Silent chains are suitable for luxury cars to reduce noise.
Types Of Timing Chains Infographic

What’s the Build Material of the Timing Chain?

Timing chains are typically made of metal, such as steel or aluminum. Some timing chains may also have a plastic or composite material coating to reduce friction and wear on the chain. The specific type of metal or coating used may vary depending on the manufacturer and the specific application of the timing chain.

If you wonder whether a VW Polo has a timing belt or a chain, this piece will provide the answer.

Advantages and Disadvantages Of a Timing Chain

Here are the timing chain’s advantages and disadvantages.


  1. Timing chains are durable and usually last for the engine’s life. Because they are made of metal, they are stable and compatible with high-powered engines.
  2. There are “silent timing chains” available for those who are not fond of the noise the timing chain makes while running.
  3. Timing chains do not require frequent maintenance like the timing belts.
  4. Timing chains are resistant to excess friction and heat.


  1. Timing chains are heavy as they’re made of metal, and they put extra weight on the engine. As a result, it can affect fuel economy.
  2. Timing chains are more difficult to access and replace than timing belts.
  3. Poorly maintained timing chains can wear out and cause engine problems.
  4. Timing chains can stretch over time if not lubricated properly, leading to inaccurate timing.


Timing chains are durable and do not require maintenance, but they are heavy and can affect fuel economy. Additionally, Poorly maintained timing chains can wear out and cause engine problems.

What are the Types of Timing Belts BMW 325i Use?

The BMW 325i models (1987 to 1993) are equipped with single-side teeth timing belts. Based on tooth shapes, timing belts come in two different categories: Curvilinear and Trapezoidal. Usually, the BMW 325i uses Curvilinear teeth timing belts.

If you’d like to know whether timing belts are directional or not, check this out.

What Other Types Of Timing Belts are Available?

The other type of timing belt is the Trapezoidal, as I’ve mentioned. Trapezoidal timing belts have teeth that are shaped like a trapezoid, with a flat top and a sloping side, unlike Curvilinear. 

They are typically made of a stronger material and are more resistant to wear than curvilinear timing belts. However, they may be more prone to slipping and not transmit power as efficiently as curvilinear belts.


Based on tooth shapes, timing belts can be curvilinear or trapezoidal. Curvilinear belts have curved teeth that transfer power more efficiently, while trapezoidal belts are less prone to slipping and wear.

Advantages and Disadvantages Of a Timing Belt

Timing belts are used to keep the camshaft and crankshaft running in sync, allowing the engine to run efficiently. While timing belts are generally reliable, they have both advantages and disadvantages. Here goes the list.


  1. Timing belts are generally quieter than timing chains. They produce less noise compared to the timing chains.
  2. Timing belts are more cost-effective than timing chains. They come at only one-third of the price of a timing chain.
  3. Timing belts are also easier to maintain than timing chains, as they do not require lubrication and are easier to access. 
  4. Timing belts are compact and lightweight. As a result, It doesn’t put extra weight and strain on the engine.


  1. Timing belts have a shorter lifespan and longevity. Over time, they become worn out and damaged.
  2. Timing belts are more likely to be damaged by heat/oil contaminations. As a result, regular inspections and more frequent replacements are required.
  3. Timing belts are unsuitable for high-powered turbo-charged engines since they are likely to break while operating.
  4. Timing belts stretch more compared to timing chains over time. As a result, the engine will fail to sync properly.


Timing belts are more efficient than timing chains, can transfer more power with less friction and heat, and are easier to maintain and replace than timing chains. However, timing belts have a shorter lifespan and longevity and are more likely to be damaged by heat/oil contaminations.


Is It Possible To Replace The Timing Belt Or Chain Myself?

Replacing the timing belt or chain in any vehicle can be a complex task that requires specialized tools and knowledge. It is generally recommended to have the timing belt or chain replaced by a professional mechanic, as attempting to do it yourself can result in costly mistakes or even engine damage.

When Does The Timing Belt Or Chain Need To Be Replaced?

Some signs that the timing belt or chain may need to be replaced include a squealing noise coming from the engine, an engine misfire, or the engine not starting. If you notice any of these symptoms, an expert must immediately check the timing belt or chain.

Why Do BMW Timing Chains Break?

The most common cause of timing chain failure is lack of maintenance. Timing chains are more prone to breaking or stretching when lubricating with old or dirty oil. Additionally, some BMW petrol engines produced between 2001-2015 have a timing chain or tensioner design problem. (2)


I appreciate your patience so much. This concludes my discussion about the BMW 325i timing belt or chain. Timing chains are used in the BMW 325i instead of belts. 

Chains are not subject to the same wear and tear as belts, so they need to be replaced less frequently. As a result, the timing chain can last for the vehicle’s lifetime and does not require a replacement anytime soon. Until next time, goodbye, and drive safe.

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Aaron Byrne

Hi, Aaron Byrne here. I'm an expert automotive mechanic with 10 years of experience. I work on engine parts especially timing belts for their repair, maintenance, and replacement.

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at with a passion for the automotive industry.