What Goes In the Dex-Cool Tank?

Dex-Cool is a coolant that cars use to stay at their best temperatures. Car owners must know what goes in the Dex-Cool tank to ensure the cooling system’s optimal performance. This guide will explain the materials used with Dex-Cool, why they are essential, and what can happen if the info isn’t followed. Additionally, it will provide tips for finding the best Dex-Cool coolant for your car and how often to change the tank content.

Engine Coolant Temperature Gauge

What is Dex-Cool?

Dex-Cool is an antifreeze/coolant used in some General Motors vehicles. It is known to be inferior to other coolants, so knowing how to use and maintain it correctly is essential. Understanding what goes in the Dex-Cool tank and when it needs servicing is essential.

Dex-Cool is a mixture of OAT ethylene glycol antifreeze and water. This mix prevents corrosion, extends the antifreeze’s life, and prevents excessive foam. The orange liquid includes inhibitors that stop mineral deposits from forming on metal surfaces, such as cylinder walls and valves.

When replacing Dex-Cool, follow manufacturer instructions and safety guidelines. When pouring coolant, use pure Dex-Cool or a 50/50 mix of Dex-Cool and distilled water—store coolants in sealed containers away from extreme temperatures or hazards. Lastly, keep antifreeze away from children, as it is highly toxic if ingested!

What is the Dex-Cool Tank?

The Dex-Cool tank is a part of your vehicle’s engine coolant system. It stores and supplies a mixture of antifreeze, water, chloride, surfactants, and other corrosion inhibitors to the engine. This specialized type of coolant is typically made from ethylene glycol, which is more efficient than plain water.

It draws in coolant from the radiator and stores it until needed. To maintain optimal performance, keeping the Dex-Cool tank filled with a 50/50 mix of Dex-Cool and clean, distilled water is essential. This will prevent contamination or sediments from building up. The performance and longevity of your car depend on it!

What Goes in the Dex-Cool Tank?

For car owners, it’s essential to maintain your car’s cooling system! One component is the Dex-Cool tank. This needs to be filled up periodically with the correct type of fluid. Know what goes in the tank and when to change it. Here, we’ll talk about the fluids and how often to change them:


Water should be 50-60% of your coolant tank. To avoid rust, use only distilled or deionized water. Adding antifreeze and water to your Dex-Cool prevents freezing. 20-40% antifreeze is recommended for most areas, but cold climates might need 60%. Use antifreeze that doesn’t corrode aluminum components. Traditional green antifreeze won’t work and can cause corrosion. SuperDEX/HOAT type or equivalent is best. Check your owner’s manual for more info.


Antifreeze, also known as engine coolant, is a must-have for your vehicle’s Dex-Cool tank. It’s made of a mix of glycol, alkali salts, and other chemicals. Its purpose? To lower the freezing point and raise the boiling issue of the coolant. This helps the engine coolant to stay at a stable temperature.

Plus, antifreeze has extra components. Corrosion inhibitors stop rust. Detergents prevent buildup. Organic Acid Technology guards against scale and oxidation. Colorants boost visibility when filling up or refilling the Dex-Cool tank.

Using a premixed solution is best to get the correct dilution rate. And use a product certified by ASTM International. This guarantees a higher quality than unrecognized brands.


Check the Dex-Cool tank levels of antifreeze and additives. Antifreeze prevents freezing and boiling. Additives in Dex-Cool coolant provide exceptional protection against corrosion and cavitation.

Types of Additives:

  • Organic acid inhibitors: Stop scale and rust buildup in the car’s cooling system by attaching to metal surfaces.
  • Surfactants: Lower surface tension of liquids for better heat transfer.
  • Buffers: Keep pH levels for improved cooling system protection.
  • Silicates: Inhibit rust and protect against calcium, magnesium, and other similar deposits.
  • Polyols: Organic acid inhibitor forms a protective film on internal components. Protect against hot spots or overly acidic solutions.

How to Fill the Dex-Cool Tank

Know your car’s needs! The Dex-Cool tank, a particular type of coolant, is essential. To keep your vehicle healthy and performing well, you must fill the Dex-Cool tank. This article will tell you what kind of coolant to use and how to do it.

Get the proper coolant and follow the instructions!

Check the level of the coolant.

To check the antifreeze level, find the marked line on the tank. Make sure it’s no more than 1/2 inch below the full mark. If it is, you need to add coolant!

Use a 50/50 mix of Dex-Cool-approved ethylene glycol and water. Then, pour the solution into an undamaged container. Be careful not to puncture it or cause any injury.

Next, pour the mixture into your vehicle’s Dex-Cool engine coolant tank. Do so safely, without splashing. Don’t overfill, as it could lead to leaks and damage.

Add water to the tank.

When adding to the Dex-Cool tank, use only distilled water. Tap or filtered water can have minerals that cause corrosion in a few years. Premixed or concentrated coolant is OK. But premix coolant is better in areas with a high mineral count. Premixed and concentrated dex-cool have a shelf life of two years. Store in a cool, dry place.

Non-dex-cool antifreeze is not recommended. It could damage aluminum radiators, thermostats, and other parts. It must be drained and replaced every two years or 30,000 miles.

Add coolant in a 50/50 ratio. Check the float level inside the radiator cap. Overfill can cause overflow. This can leak onto hot surfaces and release hazardous fumes. Plus, it could lead to fines for discharging dangerous substances into waterways.

Add antifreeze and additives.

To fill your Dex-Cool tank, you need antifreeze and additives. Two types of antifreeze are ethylene glycol and propylene glycol. Ethylene glycol is better for high temps and freezing, while propylene glycol works with cooling systems. Make sure to select an antifreeze compatible with your vehicle and Dex-Cool.

Use enough for a 50/50 water and antifreeze mixture in the tank. Don’t mix different coolant brands, reducing the cooling system’s effectiveness.

Add necessary additives like alkaline or acid inhibitors, anti-foaming agents, rust inhibitors, and antioxidants. Check your owner’s manual for the recommended amounts. Finally, cap the fill neck securely after filling.


Eventually, motor oil and Dex-Cool coolant can be added to the Dex-Cool tank. Yet, it’s essential to read the instructions on the bottles to determine if they’re compatible. Plus, don’t overfill the container. Too much of either of these substances can lead to engine issues.

Car owners and mechanics should contact the local manufacturer for product recommendations before adding anything to a vehicle’s Dex-Cool container.

Frequently Asked Questions

What is Dex-Cool?

Dex-Cool is a coolant used in many vehicles with an extended service life of up to 5 years or 150,000 miles. It is a modern coolant containing a particular phosphate type called 2-EHA.

What is the purpose of Dex-Cool?

The purpose of Dex-Cool is to help reduce corrosion in the cooling system and to help keep the engine running cooler and more efficiently. It also helps to keep the engine from overheating.

What goes in the Dex-Cool tank?

The Dex-Cool tank should be filled with a 50/50 mixture of Dex-Cool coolant and water. It is essential to use a high-quality coolant and not mix different types of coolants.