How long does Subaru engine coolant last?

In modern Subarus, coolant life depends on the formulation used and the vehicle’s conditions. With Subaru Genuine Long Life Coolant, a typical service window is about 100,000 miles or 8–10 years, while older Subarus using conventional coolant usually require more frequent changes—roughly every 2–3 years or 30,000–60,000 miles. Always consult your owner's manual for the exact interval and monitor the cooling system for signs of wear or leaks.

What determines coolant life

Several factors influence how long coolant remains effective, including the coolant formulation, climate, driving style, and maintenance habits. Understanding these variables helps determine when a replacement is due.

Different coolant types Subaru uses

Subaru has used two main coolant formulations across its lineup. The replacement interval depends on which formulation your car has.

• Subaru Genuine Long Life Coolant (often supplied as a premixed 50/50 solution). Vehicles designed for long-life coolant commonly specify a service interval around 100,000 miles or 8–10 years, depending on model and driving conditions. This coolant is designed to reduce corrosion and extend service intervals when used as directed; do not mix with incompatible formulas.


• Conventional or traditional coolant (older models or certain markets). This older formulation typically requires more frequent changes—roughly every 2–3 years or about 30,000–60,000 miles—to maintain protection and prevent deposits.

Note: The exact interval varies by model year, climate, and coolant type. Always verify with the manual or a Subaru service professional.

How to identify which coolant your Subaru uses

Check the owner’s manual or the coolant specification label under the hood to confirm the correct coolant type and replacement interval for your vehicle. If you’re unsure, a dealer or trusted shop can confirm which formulation your engine requires.

Recommended maintenance intervals by coolant type

Based on the coolant type, here are practical targets you can use to plan maintenance.

• Long Life Coolant: typically up to 100,000 miles (approximately 160,000 km) or 8–10 years, whichever comes first. Some models and climates may warrant shorter intervals; always follow the manual.


• Conventional Coolant: commonly 30,000–60,000 miles (about 50,000–100,000 km) or 2–3 years, depending on the vehicle’s condition and usage.


• Uncertain or mixed coolant systems: when in doubt, adopt a conservative approach and plan for service around 60,000 miles or 5 years, then adjust based on inspection findings and manual guidance.

Because Subaru models and regional specifications differ, the exact interval can vary. When in doubt, err on the side of more frequent checks to protect the cooling system from corrosion and overheating.

Tips to maximize coolant life

Simple, proactive steps can extend coolant life and help prevent cooling-system failures.

• Inspect for leaks around hoses, radiators, clamps, and the water pump; repair any seepage promptly.


• Check coolant level when the engine is cold and top up with the correct type if needed; never mix different coolant formulations in the system.


• Inspect the radiator cap and pressure system; a faulty cap can cause gradual loss of cooling efficiency.


• Flush the cooling system and replace coolant at the interval recommended by Subaru or your technician, using the specified coolant type.

A well-maintained cooling system reduces the risk of deposits and corrosion, helping the coolant perform as intended for longer.

Signs your coolant needs replacement

Be alert for indicators of degraded coolant or a failing cooling system.

• Overheating or rising engine temperature under normal driving conditions.


• Milky or discolored coolant, which can signal contamination from oil or corrosion products.


• Low coolant level with visible leaks or deteriorated hoses.


• Unusual sweet odor around the engine bay or radiator area, suggesting leaks or boiling coolant.

If you notice any of these signs, have the cooling system inspected by a qualified technician promptly to prevent engine damage.

Summary

Subaru coolant longevity hinges on the formulation and operating conditions. For vehicles equipped with Subaru Genuine Long Life Coolant, expect approximately 100,000 miles or 8–10 years between changes, while older models using conventional coolant typically require replacements every 2–3 years (roughly 30,000–60,000 miles). Always consult your exact model’s manual for the authoritative interval, and perform regular inspections to catch leaks, corrosion, or contamination early.

Why is my Subaru using so much coolant?

Causes of Subaru Coolant Leaks
Damaged or worn out hoses: The hoses that carry the coolant through the engine can become worn out or damaged over time, leading to coolant leaks. Faulty radiator: The radiator is responsible for cooling the coolant fluid, and a faulty radiator can lead to leaks.

Do Subaru's need special coolant?

Yes, Subarus need a specific coolant, primarily the factory-filled "Super Coolant," which is a special blue Subaru coolant. Before 2008, Subarus used a long-life green coolant. While a high-quality universal Asian blue coolant can be used, it's crucial to use the correct type for your specific Subaru model and year to ensure proper corrosion protection, especially for its aluminum engine components.
 
Coolant types and considerations

• Blue Subaru Super Coolant: This is the current standard, introduced after 2008, and is a premixed, long-life formula designed specifically for Subaru's aluminum engines. It has a much longer service interval than older coolants. 
• Green Subaru Long Life Coolant: This was used in Subarus before 2008. It is an ethylene glycol-based coolant that is not premixed and requires mixing with water to the correct ratio, which can be more challenging to get right. 
• Universal Asian Blue Coolant: A high-quality universal Asian blue coolant can be used as a substitute for Subaru's blue Super Coolant. This coolant is also designed to protect aluminum engines and can be a good option if you can't get the Subaru-brand product. 

Important tips

• Always check your owner's manual: The most accurate information for your specific Subaru model will be in your owner's manual. 
• Don't mix coolants: Never mix green and blue coolant, as they are not formulated to be compatible with each other. 
• Consider the warranty: If your car is still under warranty, using the specified Subaru coolant is recommended to avoid voiding the warranty. 
• Don't use universal coolants indiscriminately: While some universal coolants may work, it's crucial to ensure the universal coolant is specifically formulated for Asian vehicles to protect against corrosion and other damage. 

How often should you change your coolant on a Subaru?

every two to five years
How often should I change my coolant? The frequency of coolant changes varies widely, but typically falls between 30,000 and 100,000 miles or every two to five years.

How long does Subaru Super coolant last?

Subaru Super Coolant is designed to last for 11 years or 137,500 miles as the initial replacement interval. After the first replacement, Subaru recommends replacing it more frequently, typically every 6 years or 75,000 miles. 
Initial interval

• The original Subaru Super Coolant (blue) is a long-life formula that doesn't require replacement for 11 years or 137,500 miles, whichever comes first. 
• For models using the older green coolant, the recommended interval is significantly shorter, around 30,000 miles or two years. 

Subsequent intervals

• Once the initial period has passed, the coolant should be changed more regularly to maintain optimal performance and protection.
• The recommended interval for subsequent changes is every 6 years or 75,000 miles. 

Factors that may require earlier replacement

• Driving conditions: In some cases, such as towing or extreme climates, a more frequent flush may be beneficial. 
• Signs of a problem: If you notice any of the following signs, have the coolant inspected and potentially flushed sooner: 
  • Coolant leaks 
  • Overheating 
  • An unusual burning odor 
  • Sediment or rust in the coolant