Whether you are a professional mechanic or weekend warrior, you might be faced with the task of storing an unused engine or transmission. Time constraints and scheduling conflicts can keep us from being able to work on hobby projects, and repair or restoration projects can take longer than originally planned. A lot of people search solutions for engine block rust removal, but the better approach is engine block rust prevention during storage. 

Preventing rust on an engine block during storage is essential for maintaining the integrity and functionality of the engine. Worldwide, corrosion of metal parts is a costly problem, with direct costs estimated at US$2.5 trillion or up to 3.4% of global GDP.   Car maintenance and repairs can get pricey. The good news is rust is avoidable with the proper steps. Spend less time on rust removal by being proactive with rust prevention — and spend more time enjoying your vehicles.

If you are dealing with a used motor, it might need special considerations in order to stay rust free while in storage. We recommend the following steps in order to best prepare the engine or similar vehicle components for storage.

Thoroughly Clean the Engine

Before storing the engine, be sure to clean it thoroughly to remove dirt, oil, grease, and existing rust.

Any contaminants left on the surface can attract moisture and contribute to rust formation.

• Degrease the engine: Use an engine degreaser to clean the engine block, especially in areas where oil or dirt has accumulated. Using a wire or nylon brush helps to break up stubborn grease and dirt. Be sure not to touch degreaser with bare hands as it is toxic and damaging to skin. Use eye protection to keep airborne particles out of your eyes.
• Remove existing rust: If there’s any rust already forming, use a wire brush or rust remover to eliminate it before storage.
• Keep water out of the interior of engine: Use painters tape or suitable cover to prevent water from getting inside of mechanical components. 

• Rinse thoroughly: Minimize the amount of degreaser used so that the rinse water is not heavily contaminated. It’s best to collect this used degreaser into a bucket or container for disposal at hazardous material facilities.

Dry the Engine Completely

Moisture is the primary cause of rust, so it’s crucial to dry the engine completely before storage.

• Air dry: Let the engine sit in a dry, warm environment to allow any residual water to evaporate. Consider using a heater or fan to accelerate drying. 
• Use compressed air: Blow compressed air into hard-to-reach areas to ensure all moisture is removed, especially in the crevices.
• Allow for sufficient time: Complete drying might take 24 hours or longer depending on the relative humidity and temperature.

Apply a Protective Coating

A protective coating will act as a barrier between the engine block and the environment, preventing moisture from coming into contact with the metal surface.

• Anti-Rust Spray: Apply a corrosion inhibitor spray, such as Zerust Axxanol Spray-G rust protectant to the entire surface of the engine block. This seals out air and moisture from the bare metal slowing down rust formation. For superior protection, Zerust offers a VCI protection engine storage bag that features the ability to protect metal parts that are uncoated with oil.
• Engine Oil: Coat internal parts of the engine (such as the cylinder walls and pistons) with a thin layer of motor oil to prevent rust.
• Fogging Oil: For an extra layer of protection, use fogging oil to coat internal parts of the engine. This is particularly useful for engines that are being stored for long periods.

Store in a Dry, Climate-Controlled Environment

The environment in which the engine is stored plays a critical role in preventing rust.

• Control humidity: Keep the engine in a dry, climate-controlled environment with low humidity to reduce moisture in the air.
• Use a dehumidifier: If you’re storing the engine in a garage or warehouse, consider using a dehumidifier to keep moisture levels down.
• Keep the engine off the ground: Place the engine on a wooden pallet or a stand to prevent direct contact with the concrete floor, which can attract moisture.

Cover the Engine

Covering the engine helps to prevent dust and moisture from settling on the surface.

• Use a Zerust VCI protection cover: Our large engine storage bag offers tough protection while keeping dust and debris off the engine. 4 mil thick polyethylene plastic provides durable protection built in VCI protection. At 26” x 24” x 46”, it’s large enough to handle most engine or large machine parts. 
• VCI Poly bags for internal parts: Our multipurpose VCI poly bags come in a wide range of sizes for smaller parts while offering built in VCI protection.  

Check on the Engine Periodically

Even if the engine is stored properly, it’s a good idea to check on it periodically to ensure no rust is forming.

• Reapply protective coating: If the storage period extends over several months, reapply the corrosion inhibitor or fogging oil as needed.
• Inspect for rust: Look for any signs of rust and take corrective action immediately if any is found.

Use Desiccant Packs

To further reduce moisture inside any enclosed storage area, place desiccant packs (silica gel or moisture-absorbing pouches) near the engine. These help absorb excess humidity and keep the surrounding air dry.

Keep Fluids in the Engine

If possible, it can be a good idea to leave fluids like coolant or antifreeze in the engine, as these fluids often contain rust inhibitors that protect the internal parts from corrosion. This may not be possible if integral components are removed such as water pumps or other parts.

By following these steps, you can effectively protect your engine block from rust during storage, ensuring it remains in good condition for future use.

If you have questions about VCI solutions for car part storage or classic car storage, we can help.

Contact Zerust for information on VCI products to help with car rust prevention by emailing us or calling (330) 405-1965.

Additional Resources:

Assessment of the Global Cost of Corrosion,  n.d., Nace International

More Blog Entries:
Optimal Auto Parts Storage Solutions Include Rust & Corrosion Inhibitors, November 22, 2022, Zerust Products Blog