Subaru largely transitioned from using timing belts to timing chains for many of its mainstream engines starting around 2012. While some Subaru engines, such as the EZ36 (3.6-liter six-cylinder Boxer engine) and diesel engines, utilized timing chains even before this period, the year 2012 marked a significant shift where many new 4th generation Subaru engines began incorporating timing chains.
The Transition to Timing Chains
Before 2012, many popular Subaru engines, including various iterations of the EJ series (like the 2.5L EJ25 engines found in Imprezas, Foresters, and Legacys), relied on timing belts. These belts require periodic replacement, typically every 60,000 to 105,000 miles, as part of routine maintenance. Failure to replace a timing belt can lead to catastrophic engine damage.
However, starting with the introduction of the FB series engines (e.g., FB20 and FB25) around 2011-2012, Subaru began to widely adopt timing chains. These new engines were designed with chains, which are lubricated by engine oil and generally designed to last the lifetime of the vehicle, significantly reducing maintenance requirements for owners.
Why the Shift to Timing Chains?
The automotive industry's move from timing belts to chains is driven by several advantages offered by chains:
- Durability: Timing chains are made of metal, making them far more robust and less prone to stretching or breaking compared to rubber-composite timing belts.
- Reduced Maintenance: Unlike belts, chains typically do not require scheduled replacement, saving owners significant maintenance costs over the vehicle's lifespan.
- Longer Lifespan: With proper lubrication and regular oil changes, timing chains are generally designed to last for the entire service life of the engine.
Identifying Your Subaru's Timing Component
To determine whether your specific Subaru model uses a timing belt or a timing chain, consider the following:
- Model Year: Vehicles from 2012 and newer are much more likely to have timing chains, especially if they feature the newer FB or FA series engines. Older models, particularly those with EJ series engines, will typically have timing belts.
- Engine Type:
- Timing Belts: Commonly found in 2.0L and 2.5L EJ series engines (e.g., EJ20, EJ25) used in various models prior to 2012.
- Timing Chains: Used in 2.0L and 2.5L FB/FA series engines (e.g., FB20, FB25, FA20), 3.0L and 3.6L EZ series (e.g., EZ30, EZ36), and all diesel engines.
Here’s a simplified breakdown of common Subaru engine types and their timing components:
| Engine Series | Engine Displacement | Common Models/Years | Timing Component |
|---|---|---|---|
| EJ | 2.0L, 2.5L | Most models pre-2012 | Timing Belt |
| FB | 2.0L, 2.5L | Most models 2012+ | Timing Chain |
| FA | 2.0L, 2.4L | BRZ, WRX, Ascent | Timing Chain |
| EZ | 3.0L, 3.6L | Outback, Tribeca | Timing Chain |
| EE | 2.0L (Diesel) | Select markets | Timing Chain |
It's always recommended to check your specific vehicle's owner's manual or consult with a qualified Subaru technician to confirm the type of timing component and its recommended maintenance schedule.
Practical Considerations for Owners
- For Belt-Driven Engines (Older Models): If your Subaru has a timing belt, adhere strictly to the manufacturer's recommended replacement intervals. This preventative maintenance is crucial to avoid serious engine damage. Often, water pump and idler pulleys are replaced simultaneously.
- For Chain-Driven Engines (Newer Models): While timing chains are generally maintenance-free, ensuring regular oil changes with the correct type of oil is vital. This keeps the chain and its tensioners properly lubricated, extending their lifespan.
