Hawk Prep Fluid 5L is specially formulated to prepare a cooling system prior to conversion to Hawk Waterless Coolants. Compatible with all engine types, it is an essential step when an engine contains or has previously contained conventional water-based cooling fluid.

After a standard drain, water may remain trapped in the engine block, cylinder head, radiator, heating system, or various pipes. Thanks to its hygroscopic properties, Hawk Prep Fluid absorbs this residual water and also helps flush out loose dirt and deposits present in the system. It thus prepares the engine before it is finally filled with the appropriate Hawk waterless cooling fluid.

Important: Hawk Prep Fluid is not the final cooling fluid. It is used during the conversion process and must be drained before refilling with the Hawk cooling fluid selected for the vehicle.

What is Hawk Prep Fluid used for?

The primary role of Prep Fluid is to minimize the quantity of water remaining in the system after draining. This step is essential to fully enjoy the benefits of a water-free cooling fluid.

Hawk recommends that , after conversion , the residual water content be ideally 3% or less. This concentration can be checked using a refractometer.

Proper preparation ensures that Hawk’s waterless cooling fluid will perform as intended and minimizes issues associated with the presence of water, such as localized boiling, vapor formation, oxidative corrosion, pressure in the cooling system, and cavitation.

The Benefits of Hawk Prep Fluid

• Preparation before switching to waterless coolant: specially developed for converting a cooling system to Hawk Waterless Coolants.
• Residual water absorption: its hygroscopic properties allow it to remove water remaining in the engine after a drain.
• Compatible with all engine types: allows you to prepare various cooling systems before selecting the Hawk fluid appropriate for the vehicle.
• Helps flush the system: helps remove loose dirt and deposits present in the cooling system.
• Water-free formulation: allows you to prepare the system without reintroducing water.
• Optimized preparation: helps achieve a residual water content of ideally 3% or less after conversion.
• Essential step in the conversion process: ensures that the Hawk cooling fluid used afterward fully retains the benefits associated with its water-free operation.

Features of Hawk Prep Fluid 5L

• Type: Cooling system preparation fluid
• Brand: Hawk Waterless Coolants
• Product: Prep Fluid
• Volume: 5 liters
• Application: Preparation prior to switching to a Hawk waterless cooling fluid
• Compatibility: All engine types
• Main function: Hygroscopic absorption of residual water
• Additional Action: Helps flush out loose dirt and deposits from the system
• Formulation: Water-free
• State: Low-viscosity synthetic liquid
• Boiling point: Above 180°C
• Freezing point: Below -40°C
• Recommended water content after conversion: Ideally 3% or less
• Water content check: Refractometer
• End use: Must be drained before final filling with the appropriate Hawk fluid
• Former brand name: Evans Waterless Coolants
• Former product name: Evans Prep Fluid

Why is it necessary to prepare the system before switching to a waterless coolant?

Simply draining the system does not always remove all the water present in a cooling system. Some of the oldcooling fluid may remain in the engine block, cylinder head, radiator, heater core, and certain pipes.

Filling the system directly with a waterless cooling fluid without properly removing this residual water is equivalent to contaminating the new cooling fluid as soon as it is put into service. However, the benefit of the Hawk system lies precisely in the removal of water and the issues associated with it.

Hawk Prep Fluid therefore serves as the intermediate step between draining the old coolant and filling the system with the new water-free coolant. Thanks to its hygroscopic properties, it absorbs the residual water present in the system. The Prep Fluid, now saturated with this water, is then drained.

The system can then be filled with the Hawk water-free cooling fluid appropriate for the vehicle, engine, and its intended use.

How do you use Hawk Prep Fluid during a conversion?

Start by draining as much of the old cooling fluid as possible. The Hawk Prep Fluid is then introduced into the system to absorb any water that could not be removed during this initial drain.

Once the preparation procedure is complete, the Prep Fluid must be completely drained. The system is then ready to receive the appropriate Hawk waterless cooling fluid.

After the conversion, Hawk recommends that the residual water content be ideally 3% or less. A refractometer can be used to check this value and verify the quality of the conversion.

Prep Fluid must not remain in the engine as the final cooling fluid. Its purpose is to prepare the cooling system before the final fill with a Hawk Waterless Coolant.

Which Hawk cooling fluid should you choose after using Prep Fluid?

Hawk Prep Fluid can be used to prepare various types of engines. However, once the cooling system has been prepared, the final cooling fluid must be selected based on the vehicle, the engine design, the materials used, and its use.

• Hawk Power Cool 180° 5L: for sports cars, tuned vehicles, race cars, and high-performance engines.
• Hawk Classic Cool 180° 5L: for classic and collector’s cars. As a general guideline, this formulation is primarily suited for vehicles from approximately 1950 to 1980. Engine design and system materials remain the primary factors in determining compatibility.
• Hawk Vintage Cool 180° 5L: for vintage and classic cars, generally applicable to vehicles up to the years 1950-1959. This formulation is particularly well-suited for older engines that use materials such as cast iron, copper, and brass.
• Hawk PowerSports R 5L: for street bikes, sport bikes, and racing bikes, particularly those with engines made primarily of aluminum.

The vehicle’s year of manufacture is only a general guide. For vintage and classic cars, engine technology and the materials used in the cooling system must also be considered before choosing between Vintage Cool and Classic Cool.

What are the benefits of switching to a Hawk water-free cooling fluid?

Preparation with Prep Fluid ensures the cooling system is properly converted to take full advantage of the properties of a Hawk waterless cooling fluid. The goal is to remove water from the system and reduce problems directly associated with its presence.

In the hottest areas of an engine, the water contained in a conventional cooling fluid can boil locally and form steam. These phenomena reduce heat transfer to metal surfaces and can create localized hot spots, promoting overheating conditions that can, in particular, contribute to a blown head gasket.

Depending on the Hawk formulation chosen, switching to a water-free coolant offers benefits such as a very high boiling point, low vapor pressure, reduced cavitation, and the absence of water-related oxidation corrosion. These properties help protect the engine, water pump, hoses, gaskets, radiator, and various components of the cooling system.

Evans Prep Fluid Becomes Hawk Prep Fluid

Evans Waterless Coolants is now known as Hawk Waterless Coolants. The product previously marketed as Evans Prep Fluid is now Hawk Prep Fluid. This change affects the brand identity only and does not alter the product’s formulation.

GT2i is an official retailer of Hawk Waterless Coolants. At GT2i, you’ll find Prep Fluid as well as the various Hawk formulations that allow you to tailor the waterless cooling fluid to your vehicle and its engine.

FAQ - Hawk Prep Fluid

What is Hawk Prep Fluid used for?
Hawk Prep Fluid is used to prepare a cooling system before converting it to a Hawk waterless coolant. Thanks to its hygroscopic properties, it removes residual water remaining in the engine after draining the old coolant.

Is Hawk Prep Fluid a cooling fluid?
Prep Fluid is a preparation fluid and is not intended to remain permanently in the engine. After the conversion process, it must be drained and replaced with the Hawk waterless cooling fluid appropriate for the vehicle.

Why isn’t a simple drain sufficient before switching to waterless coolant?
Even after draining the coolant, water may remain trapped in the engine block, cylinder head, radiator, heater, or certain lines. Prep Fluid helps remove this residual water to properly prepare the cooling system.

What quantity of water might remain after the conversion?
Hawk recommends that the residual water content ideally be 3% or less to fully benefit from the properties of the waterless cooling fluid.

How do you check the quantity of remaining water?
The water content can be checked using a refractometer. This measurement allows you to verify the quality of the water circuit preparation.

Does Hawk Prep Fluid clean the cooling system?
Its primary function isto absorb residual water. As it flows through the system, it also helps flush out loose dirt and deposits. However, it should not be confused with a product specifically designed for decoking or intensive cleaning of a heavily contaminated system.

Should the Prep Fluid be drained before adding the Hawk coolant?
Yes. The Prep Fluid must be drained after the preparation phase. The cooling system can then be filled with the Hawk water-free cooling fluid suitable for the engine.

Which Hawk coolant should be used after the Prep Fluid?
The choice depends on the vehicle and engine. Power Cool 180° is intended for sports cars and high-performance engines; Classic Cool 180° for classic cars from approximately 1950 to 1980; Vintage Cool 180° for older vehicles, specifically those dating back to the 1950s; and PowerSports R for street, sport, and racing motorcycles.

Why is it necessary to remove water before adding a Hawk coolant?
The goal of the Hawk system is precisely to operate without water. Reducing residual water helps limit the issues associated with its presence—including localized boiling, vapor formation, oxidation corrosion, and cavitation—and allows you to fully benefit from the properties of the Hawk fluid used afterward.

Can Hawk Prep Fluid be reused after a conversion?
The Prep Fluid collects residual water present in the system during preparation. Once used and saturated with water, it should not be considered a new Prep Fluid for performing another conversion.

Are Evans Prep Fluid and Hawk Prep Fluid the same product?
Yes. Evans Waterless Coolants has become Hawk Waterless Coolants. The former Evans Prep Fluid is now marketed under the name Hawk Prep Fluid. The formulation remains unchanged.