2018 Nissan Altima Coolant Capacity & Type: A Complete Guide

The 2018 Nissan Altima holds between 7.8 and 9.4 quarts (7.4 to 8.9 liters) of engine coolant, depending on the engine option under the hood. Keeping your Altima’s cooling system filled with the correct type of antifreeze is one of the most important things you can do to prevent catastrophic engine overheating and expensive repairs.

As an ASE-certified master technician, I’ve serviced countless Nissan L33-generation Altimas. Below is your comprehensive guide to getting the coolant capacity, type, and maintenance schedule right for your 2018 Nissan Altima.

Quick answer

When servicing your 2018 Altima, keep these essential specifications in mind:

• Total cooling system capacity: 7.8 quarts (7.4 L) for the 2.5L 4-cylinder, and 9.4 quarts (8.9 L) for the 3.5L V6 (including the reservoir).
• OEM coolant spec: Genuine Nissan Long Life Antifreeze/Coolant (Blue). This is a Phosphated Organic Acid Technology (P-OAT) coolant. Do not mix it with older green IAT coolants or universal orange OAT coolants.
• Mix ratio: 50/50 mix of coolant and distilled water (most Nissan Blue coolant is sold as a 50/50 pre-mix right out of the bottle).

Capacity by engine option

The exact amount of coolant your vehicle will take during a completely dry fill varies by engine size. Note that a standard drain-and-fill will usually take slightly less than the total system capacity, as some fluid remains in the engine block and heater core.

Note: Capacities include the coolant reservoir tank (roughly 0.8 quarts).

Flush interval

Nissan uses a very robust factory-fill coolant, but it doesn't last forever. The additives that protect your aluminum engine block and radiator from internal corrosion eventually break down.

• Normal Duty: Nissan recommends replacing the factory-fill Blue coolant after 10 years or 105,000 miles, whichever comes first. After the initial replacement, subsequent flushes should be performed every 5 years or 75,000 miles.
• Severe Duty: If you drive in extreme temperatures, idle extensively, or make frequent short trips where the engine doesn't fully warm up, consider having a drain-and-fill performed every 60,000 miles to ensure maximum corrosion protection.

How to refill & bleed

Getting all the air out of a modern cooling system is critical. Air pockets can cause the heater to blow cold, the thermostat to malfunction, and the engine to overheat.

1. Prep the vehicle: Park on a level surface (or with the front end slightly elevated). Wait until the engine is completely cold before opening the radiator cap.
2. Fill the radiator: Attach a spill-free funnel to the radiator neck. Slowly pour in the 50/50 pre-mixed Nissan Blue coolant until the radiator is full. Fill the plastic reservoir to the "MAX" line.
3. Start the engine: Turn the engine on and set the cabin heater to maximum heat and the blower fan to low. This opens the heater core circuit.
4. Bleed the system: Let the engine idle until it reaches operating temperature and the thermostat opens (you will feel the lower radiator hose get hot). You will see air bubbles burping up through your spill-free funnel.
5. Rev the engine: Nissans are notorious for trapping air in the heater core. Hold the engine RPMs at about 2,500 for 10-second bursts to push trapped air through the system.
6. Final top-off: Once the bubbling stops and the heater blows consistently hot air, turn off the engine. Let it cool, remove the funnel, install the radiator cap, and double-check the reservoir level.

Pro tip: Using a vacuum-fill tool is highly recommended for the 3.5L V6 to completely eliminate the risk of trapped air pockets.

Common cooling system issues

The 2018 Altima (part of the 5th generation L33 chassis) is generally quite reliable, but there are a few cooling system quirks to watch out for:

• Radiator Fan Assembly Failures: The cooling fan motors on this generation of Altima are known to wear out prematurely. If your car overheats at idle or in stop-and-go traffic but cools down at highway speeds, check to see if the fans are spinning.
• Sticking Thermostats: If you notice erratic temperature gauge readings or poor heater performance, the thermostat may be failing to open or close properly.
• Water Pump Weepage: While not exceptionally common, the water pump on the 2.5L engine can develop a slow leak from the weep hole as it ages. Inspect the passenger side of the engine for crusty blue residue during oil changes.

If you are dealing with persistent overheating, fan failures, or need a professional coolant flush, don't leave it to chance. Find a trusted shop on Repairius.