2018 Chevrolet Suburban Fluid Type Specs

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil	0W-20 (dexos1 Gen 2)	8.0 quarts (7.6 liters)
Engine Coolant	ACDelco DEX-COOL Orange (GM 6277M)	14.6 quarts (13.8 liters)
Automatic Transmission Fluid	DEXRON VI	12.4 quarts (11.7 liters) (approx.)
Transfer Case Fluid	DEXRON VI	1.6 quarts (1.5 liters)
Front Differential	75W-90 Synthetic Gear Oil (GL-5)	1.8 quarts (1.7 liters)
Rear Differential	75W-85 Synthetic Gear Oil (GL-5)	2.75 quarts (2.6 liters)
Brake Fluid	DOT 3	As needed
Power Steering Fluid	DEXRON VI	As needed
Washer Fluid	-	As needed

Engine Oil

The 2018 Chevrolet Suburban with the 5.3L V8 engine requires 0W-20 viscosity grade engine oil that meets the GM dexos1 Gen 2 specification. This specific oil is a full synthetic formula designed to provide optimal protection, fuel efficiency, and performance for modern GM engines. The dexos1 Gen 2 specification is crucial as it helps to prevent low-speed pre-ignition (LSPI), a phenomenon that can cause catastrophic engine damage. Always look for the dexos1 Gen 2 logo on the bottle to ensure you are using the correct oil.

The engine oil capacity for the 5.3L V8 is 8.0 quarts (7.6 liters) with a filter change. It is essential to use a high-quality oil filter to ensure proper filtration and oil flow. The oil and filter should be changed according to the oil life monitor system in the vehicle, which will typically recommend an interval of 5,000 to 7,500 miles depending on driving conditions.

Engine Coolant

The 2018 Suburban uses ACDelco DEX-COOL Orange coolant, which is an Organic Acid Technology (OAT) coolant. It meets the GM 6277M specification. This coolant is designed for long life, typically up to 5 years or 150,000 miles, but it is always a good idea to check the owner's manual for the recommended service interval. When topping off or refilling the system, it is critical to use only DEX-COOL or a compatible OAT coolant. Mixing DEX-COOL with other coolant types, such as Hybrid Organic Acid Technology (HOAT) or traditional green coolants, can cause the coolant to gel, leading to blockages in the cooling system and potential engine damage.

The cooling system capacity is approximately 14.6 quarts (13.8 liters). Always use a 50/50 mixture of coolant and distilled water to ensure proper freeze and boil-over protection.

Automatic Transmission Fluid

The 6-speed and 8-speed automatic transmissions in the 2018 Suburban require DEXRON VI automatic transmission fluid. DEXRON VI is a specific formulation designed to provide consistent shift performance and durability for modern GM automatic transmissions. Never use a universal or multi-vehicle ATF, as this can lead to poor shifting, transmission shudder, and eventual transmission failure.

The transmission fluid capacity is approximately 12.4 quarts (11.7 liters) for a complete fill, but a typical drain and fill will only replace about half of this amount. The transmission fluid and filter should be changed every 45,000 miles for severe service (towing, heavy city driving) or as recommended in the owner's manual for normal service. Many modern GM transmissions do not have a dipstick, so checking the fluid level and condition should be done by a qualified technician.

Transfer Case Fluid

For 4WD models, the transfer case requires DEXRON VI automatic transmission fluid. This is the same fluid used in the automatic transmission, which simplifies service. The transfer case capacity is 1.6 quarts (1.5 liters). The transfer case fluid should be changed every 50,000 miles, or more frequently if the vehicle is used for off-roading or heavy towing.

Front and Rear Differential

The front differential on 4WD models requires 75W-90 Synthetic Gear Oil that meets the GL-5 specification. The capacity is 1.8 quarts (1.7 liters). The rear differential requires 75W-85 Synthetic Gear Oil that also meets the GL-5 specification, and the capacity is 2.75 quarts (2.6 liters). Some rear differentials may require a limited-slip additive, so it is important to verify this in the owner's manual or with a GM dealer. The differential fluid should be changed every 50,000 to 100,000 miles, depending on use.

Brake Fluid

The 2018 Chevrolet Suburban requires DOT 3 brake fluid. It is important to use a high-quality brake fluid from a sealed container to ensure that it has not absorbed moisture from the air. Brake fluid is hygroscopic, meaning it absorbs moisture, which can lower the boiling point of the fluid and lead to a spongy brake pedal or brake failure. The brake fluid should be changed every 2 to 3 years, regardless of mileage.

Power Steering Fluid

The power steering system in the 2018 Suburban uses DEXRON VI automatic transmission fluid as power steering fluid. This is a common practice for many modern GM vehicles. The power steering fluid should be checked at regular intervals and topped off as needed. A complete fluid flush is recommended if the fluid appears dirty or every 50,000 miles.

Washer Fluid

There is no specific brand or type of washer fluid required for the 2018 Suburban. Any quality washer fluid will work. It is a good idea to use a washer fluid with a de-icing agent in the winter to prevent the fluid from freezing on the windshield.

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