Parts for your 2012 Subaru Impreza

The Timing Belt on the 2012 Subaru Impreza

The 2012 Subaru Impreza, depending on the engine variant, does not use a traditional timing belt in all models. Specifically, the models equipped with the 2.0-litre naturally aspirated boxer engine and the 2.5-litre boxer engine typically come with a timing chain, not a timing belt. This is a notable design choice by Subaru that affects maintenance routines and overall engine durability.

Timing belts and timing chains serve the same essential purpose in an engine. Their job is to synchronise the rotation of the crankshaft and camshaft, ensuring that the engine's valves open and close at exactly the right times during each cylinder's intake and exhaust strokes. This coordination is crucial for the engine to run smoothly and efficiently. However, the materials and replacement intervals of timing belts and chains differ significantly.

The 2012 Subaru Impreza's use of a timing chain rather than a timing belt is primarily due to the design of the boxer engine. A timing chain is made of metal links similar to a bicycle chain and is housed inside the engine. This shielded environment protects it from debris, oil, and wear caused by external contaminants, giving it a distinct advantage in terms of longevity.

Because the timing chain is a metal component designed to last the lifetime of the engine, it does not typically require regular replacement like a timing belt would. Timing belts, usually made from reinforced rubber with fabric and fibre layers, are exposed to heat and wear, which means they have a limited lifespan - commonly anywhere between 80,000 to 120,000 kilometres, or about 5 to 7 years. If a timing belt fails, it can cause serious engine damage, particularly in interference engines where valve and piston collisions occur.

With the 2012 Subaru Impreza's timing chain system, owners benefit from a piece that is generally more durable and consistent over time. That said, timing chains are not entirely immune to wear or stretching. Over a long period and high mileage, a timing chain can stretch or the tensioner that keeps it tight may wear out, potentially causing noise or affecting timing accuracy. However, these issues are usually only a concern after well over 150,000 kilometres - far beyond a typical maintenance schedule.

Because of this, maintenance on the timing chain for the 2012 Subaru Impreza mostly involves routine checks rather than scheduled replacements. During regular servicing, mechanics will listen for unusual rattling noises from the engine that could indicate a loose chain or failing tensioner. They will also check for any oil contamination or wear signs in the timing chain area during a more comprehensive service. Proper engine oil quality and change intervals are critical to ensuring the timing chain remains in good working order, as oil lubricates the chain and its guides.

To keep the timing chain happy, it is best to stick to the manufacturer's recommended oil change schedule using the correct grade of oil. Dirty or degraded oil can accelerate wear on the timing chain components and increase the risk of failure. This is a huge bonus for owners who want a piece of mind service experience without the hassle of frequent timing belt replacements.

In the less common scenario that the timing chain or tensioners do wear out or fail, repairs can be more involved and costly compared to a timing belt replacement. The engine timing cover usually needs to be removed, and sometimes parts of the engine need to be dismantled to access these components. This is why routine oil changes and careful listening during engine starts and idling can help spot issues early.

To summarise the timing system on the 2012 Subaru Impreza, it uses a timing chain rather than a timing belt, aligning with Subaru's engineering preference for boxer engines. The chain's metal construction and internal positioning mean it generally requires less frequent service and has a longer lifespan. For drivers and service technicians, this translates to lower maintenance costs and fewer concerns about catastrophic engine damage related to timing component failure.

So, if someone is cruising along in a 2012 Subaru Impreza and wondering about timing belt changes, they can relax a bit knowing their vehicle does not have a timing belt in the first place. Keeping on top of regular oil changes and monitoring for any unusual engine noises during servicing is the best way to safeguard the timing chain and ensure the engine continues to run smoothly for many kilometres.