How often should Subaru coolant be changed?

In most modern Subarus, coolant change intervals hinge on the type of coolant used. The standard guidance for Subaru’s long-life coolant is to replace it every 100,000 miles or 10 years, whichever comes first. If your model uses conventional coolant or is older, the interval is typically shorter—about every 2–3 years or 30,000 miles—though you should always verify with your owner’s manual or a Subaru dealer for your exact model.

The exact timing can vary by model year and climate, and driving conditions such as frequent short trips or heavy towing can shorten coolant life. This article reviews the official guidance, how to determine which interval applies to you, and what to expect during a coolant service.

Official guidance and typical intervals

Below are the intervals most commonly cited for Subaru models, depending on coolant type. These reflect the guidance you’ll typically find in owner’s manuals and dealer recommendations, though always confirm for your specific year and engine.

• Long-life Subaru coolant: replace at 100,000 miles (160,000 km) or 10 years, whichever comes first.


• Conventional coolant (older or non-long-life formulations): replace approximately every 2–3 years or 30,000 miles, subject to manual confirmation.


• Specialty or model-specific coolants may have different intervals; always verify with the dealer for your exact model/year.

In practice, most newer Subarus that use Subaru’s long-life coolant are scheduled for a first coolant change around the 100,000-mile mark, with subsequent changes spaced by another 100,000 miles or 10 years, barring any leaks or contamination.

Factors that can affect replacement timing

Several conditions can influence when coolant should be changed beyond the base interval. Consider these factors when planning maintenance.

• Climate and driving conditions: harsh heat, extreme cold, or frequent towing can stress the cooling system and shorten coolant life.


• Driving patterns: many short trips prevent the engine from reaching full operating temperature, accelerating coolant degradation.


• Coolant type and prior service: using a coolant not recommended by Subaru or skipping the scheduled flush can alter intervals.


• System integrity: leaks, contaminated coolant (rust, sludge), or a degraded radiator cap can necessitate earlier service.

Always tailor the interval to your vehicle’s history, and consult a Subaru dealer if you notice signs of trouble or if your manual suggests a different schedule for your model.

Signs that coolant may need replacement

Be alert to indicators that the cooling system needs attention before the next scheduled change. If you notice any of the following, have the system inspected promptly.

• Overheating or consistently rising engine temperature


• Low coolant level with visible leaks around hoses, radiator, or water pump


• Discolored, rusty, or sludgy coolant in the reservoir


• Sweet odor near the engine bay or coolant reservoir that suggests a leak


• White milky residue in the coolant reservoir, which can indicate contamination or a head gasket issue

If any of these symptoms appear, don’t wait for the next scheduled change—arrange a service inspection to determine the cause and the appropriate interval adjustment.

What to expect during a coolant service

When you bring your Subaru in for a coolant service, expect the process to include a system flush (if required), replacement with the correct Subaru-approved coolant, and a check of related components. Here are the typical steps car owners should anticipate.

1. Verify the correct coolant type for your model/year and the service interval from the owner’s manual or dealer.


2. Perform a thorough flush of the cooling system if contamination or old coolant warrants it.


3. Refill with the appropriate Subaru-approved coolant and bleed the system to remove air pockets.


4. Inspect hoses, radiator, water pump, and radiator cap for wear or leaks, and replace any worn parts as needed.

Regularly scheduled coolant maintenance helps prevent overheating, protects the engine, and supports reliable performance across seasons.

Summary

For most modern Subarus equipped with long-life coolant, aim for a coolant change every 100,000 miles or 10 years, whichever comes first. If your vehicle uses conventional coolant or is older, a more frequent interval—typically around 2–3 years or 30,000 miles—may apply. Always consult your owner’s manual or a Subaru dealer for model-specific guidance, consider climate and driving conditions, and monitor for signs of cooling-system trouble. A proactive coolant service can prevent overheating and extend engine life.

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.

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. 

Is a coolant flush really necessary?

Yes, a coolant flush is necessary for routine preventive maintenance, as it removes debris and old, degraded coolant that can cause overheating, corrosion, and expensive engine damage over time. It cleans out rust and scale deposits, restores the coolant's ability to transfer heat efficiently, and prevents the buildup of acidic and contaminated fluid in the cooling system. 
You can watch this video to see why coolant flushes are important for your car's engine: 58sWhat Dennis DoesYouTube · Nov 15, 2018
Why a coolant flush is necessary

• Prevents engine overheating: Coolant can become contaminated with rust and scale, which can clog passages and block the system's ability to transfer heat. A flush removes these blockages and replaces old coolant with fresh fluid. 
• Protects against corrosion: Over time, coolant becomes acidic, which can corrode metal components in the engine and radiator. Flushing the system removes acidic fluid and replaces it with new coolant that contains anti-corrosive additives. 
• Maintains the effectiveness of coolant: Coolant contains additives that break down over time. A flush replaces old, ineffective coolant with new fluid, ensuring proper freeze protection and heat transfer. 
• Prevents costly repairs: By preventing overheating, corrosion, and clogs, a regular coolant flush helps avoid catastrophic and expensive engine damage. 
• Identifies underlying issues: A flush provides an opportunity for a mechanic to inspect the system. If oil or other contaminants are found in the old coolant, it can indicate other problems that need to be addressed. 

This video demonstrates how to perform a coolant flush: 30sChrisFixYouTube · Mar 6, 2015
When to get a coolant flush

• According to your manufacturer's schedule: Check your owner's manual for the recommended service intervals. 
• If you buy a used car: It is especially important to flush the coolant if you don't know the service history of a high-mileage used car. 
• If you notice signs of a problem: Look for signs of overheating, or if you find low coolant levels and suspect a leak or contamination. 

Can coolant last 100,000 miles?

Depending on the vehicle and the coolant, the average time between flushes is two years or 30,000 miles for silicated coolants and up to five years or 100,000 miles for an extended drain coolant. Periodically, the coolant needs to be tested every 50,000 miles.