Subaru Ascent 2018-2026 Owner's Manual: Cooling system

Safety precautions

WARNING

Never attempt to remove the radiator cap on your Subaru Ascent while the engine is still hot or running. The cooling system operates under pressure, and opening the cap prematurely can release a burst of boiling coolant, resulting in severe burns and serious injury.

CAUTION

• Your Subaru Ascent is factory-filled with SUBARU SUPER COOLANT, which is designed for extended service life and typically does not require replacement for up to 11 years or 137,500 miles (220,000 km). During this period, do not mix it with other coolant types or brands.

  Mixing different coolants may reduce effectiveness and shorten the service interval. If topping up is required, always use SUBARU SUPER COOLANT to maintain proper system performance.

• Avoid spilling engine coolant onto painted surfaces of your Subaru Ascent. The chemical composition of the coolant may damage the paint and lead to surface deterioration.

Cooling fan, hose and connections

Your Subaru Ascent is equipped with an electrically controlled cooling fan that automatically activates when the engine coolant reaches a specified temperature. This system ensures that the engine maintains optimal operating conditions under various driving environments.

1. Normal operating range

If the radiator cooling fan in your Subaru Ascent fails to operate even when the temperature gauge rises above the normal range, it may indicate an issue within the cooling fan circuit.

If the fuse is intact and the problem persists, have the cooling system inspected by an authorized SUBARU dealer without delay.

Additionally, if you find yourself needing to frequently add coolant between scheduled services, it may suggest a leak or system malfunction. In such cases, it is recommended to have your Subaru Ascent thoroughly checked by a qualified technician.

Engine coolant

Checking the coolant level

WARNING

Never remove the radiator cap until the engine has completely cooled down. Opening the cooling system under pressure can result in the release of hot coolant, which may cause severe burns.

1. "FULL" level mark
2. "LOW" level mark

It is recommended to check the coolant level of your Subaru Ascent at every fuel stop to ensure proper engine cooling performance.

1. Inspect the coolant level through the side of the reservoir tank while the engine is cold.

2. If the coolant level is near or below the "LOW" mark, add coolant until it reaches the "FULL" mark. If the reservoir is empty, remove the radiator cap carefully and refill the radiator to just below the filler neck, as shown in the illustration.

1. Fill up to this level.

3. After refilling both the radiator and reservoir tank, securely reinstall the radiator cap. Make sure that the rubber sealing gaskets are properly positioned to maintain system pressure and prevent leaks.

CAUTION

• When adding coolant to your Subaru Ascent, avoid spills. Coolant contacting the exhaust system may cause smoke, unpleasant odors, or even fire hazards. Clean any spills immediately.
• Do not allow coolant to contact painted body panels, as it may damage the finish and lead to discoloration.

Changing the coolant

Replacing engine coolant in your Subaru Ascent can be a complex procedure requiring proper tools and knowledge. For this reason, it is recommended that coolant replacement be carried out by an authorized SUBARU dealer.

The coolant should be replaced according to the intervals specified in the "Warranty and Maintenance Booklet" to ensure optimal engine protection and long-term reliability.

Proper maintenance of the cooling system in your Subaru Ascent is essential for preventing overheating, ensuring efficient engine operation, and extending the lifespan of critical components.