Is It A Good Idea To Use Old Motor Oil To Preserve Wood?

Old Motor Oil To Preserve Wood

Last Updated on July 20, 2023 By Emma W. Thomas

Using old motor oil to preserve wood is not a good idea. Motor oil contains harmful chemicals and pollutants that can leach into the soil and environment, posing serious risks to human health and ecosystems. Additionally, it does not provide effective wood preservation and can result in unpleasant odors and potential damage to the wood’s appearance. There are safer and more environmentally friendly alternatives, such as wood sealers and preservatives specifically designed for this purpose.

Is It A Good Idea To Use Old Motor Oil To Preserve Wood?

Wood preservation is crucial to enhance its durability and protect it from moisture, pests, and decay. While there are various options available for wood preservation, you may have come across the idea of using old motor oil. However, it’s essential to understand the implications and potential risks involved before going ahead with this method. In this listicle, we will explore whether using old motor oil to preserve wood is a good idea or not.

  1. Contaminants and Toxins:
    Old motor oil contains contaminants such as heavy metals, solvents, and other harmful chemicals that can pose health risks when exposed to humans or animals. These contaminants can leach into the soil, water sources, or surrounding environment, causing environmental pollution.
  2. Toxicity to Wood:
    Motor oil does not penetrate wood effectively for long-term preservation. It eventually dries out, creating an oily surface that attracts dust and dirt, making it difficult to clean or refinish the wood in the future. The oil may also interfere with the natural aging process of wood, affecting its appearance.
  3. Fire Hazard:
    Using motor oil on wood increases the risk of fire. Oil-soaked wood can ignite more easily and burn more intensely, posing a significant safety concern, especially if used indoors or in close proximity to heat sources.
  4. Deforestation and Sustainability:
    Using old motor oil as a wood preservative does not align with sustainable practices and contributes to environmental degradation. Sourcing and disposing of used motor oil can harm ecosystems, as well as indirectly support the oil industry’s harmful activities.
  5. Alternative Wood Preservatives:
    There are several proven, safe, and environmentally friendly alternatives for wood preservation. Some popular choices include:
    • Wood Preservatives: Utilize specific wood preservatives designed to protect against termites, fungi, rot, and other wood-damaging organisms. Choose water-based preservatives that are eco-friendly and safe for humans and animals.
    • Natural Oils: Natural oils like linseed oil, tung oil, and walnut oil can help enhance the wood’s natural beauty while providing protection against moisture and decay.
    • Varnishes and Paints: Sealants like varnishes or paints form a protective layer on the wood, preventing moisture penetration, UV damage, and pests.

How Does Used Motor Oil Protect Wood?

Used motor oil is only applicable for outdoor wood. It is because once applied, oil seeps deeper into the wood. The continuous application makes the wood to be oversaturated, leading to leakage. When you use it indoors, it creates an unnecessary mess. This oil also contains some toxic ingredients which do not dry off quickly. It is a good option for protecting outdoor wood despite being annoyingly messy.

 Used motor oil has been popular for preserving wood and outdoor wooden furniture since the 1900s. But, the substance has limited use, especially in environmental conditions. When used in hot and dry areas, it could cause a fire outbreak since both the oil and wood are highly flammable.

What Can You Use To Protect Wood Other Than Used Motor Oil?

Oil finishes are the best wood protectors that are most commonly used for kitchen utensils and furniture. The oil used must be eco-friendly, unlike used motor oil. It should also be non-toxic and food safe since there are children and pets in most households. Using toxic oil for wood protection would be hazardous to them. Some of the most common non-toxic and eco-friendly oils used for wood preservation include;

Mineral Oil

Mineral oil is derived from petroleum that is food-friendly and non-toxic. It is used to describe most clear oils. Some people use it to protect wooden kitchenware such as chopping boards, wooden bowls, and other wooden utensils. Mineral oil is also present in baby oil and other products as the main ingredient is safe to use. Studies and tests carried out have proven that mineral oil is safe for skincare use. It is the best choice for use, especially on frequently used kitchen items.

Tung Oil

Tung oil is a wood finish oil derived from plants. Just like mineral oil, it is clear with a quick-drying property. It also penetrates deeply into the wood compared to other oils hence offering maximum wood protection. This oil is derived from Tung seeds which were first discovered in East Asia and have since become a staple finishing ingredient for most artisans. Tung oil is food safe, eco-friendly, and non-toxic hence suitable for use on indoor wooden furniture.

The main problem with Tung oil is that it is difficult to find. For this reason, sellers and craftsmen combine it with water, and the end product does not work as well as the original oil. Marketers also tend to mislabel other products that are nothing close to it. Most people prefer using Tung oil as it does not yellow the wooden furniture or varnish like other products such as linseed oil.

Danish Oil

Danish is a wood-protecting oil commonly used by craftsmen. Danish oil is ambiguously used to refer to different oily wood finishing oils. It comprises different oils such as Tung oil, linseed oil, and other ingredients like drying agents, thickeners, and thinners. Danish oil is a term craftsman used to generalize oil-based wood protectors and finishes.

Linseed Oil

Linseed is also commonly known as flaxseed oil. Linseed is a hand-rubbed type of protective wood oil and works by saturating deep into the wood grains offering protection from water and scratches. This product is eco-friendly as it is derived from flaxseed plants and processed in many ways it can be used while raw, boiled, or when polymerized. The purest form of linseed is when raw. When in this form, it is impossible to use it for wooden furniture protection as it takes very long to dry to the extent of weeks and months. 

When boiled, it produces some hazardous compounds and hence cannot be used for indoor furniture.  Linseed oil is great when is polymerized since it becomes non-toxic and food-friendly with fast-drying components.

There is no better or bad wood oil as they all serve the same purpose of protecting and preserving wooden surfaces. The only difference is that some have specific roles and uses. The table below shows a summary of the best wood oil available and its effect on wood. 

Boiled linseed oil

Danish oil

Tung oil
Ease of useeasyEasyeasy
Food safeYesYesYes
Drying time24 hours4-6 hours24 hours
Change of wood colorDarkenSlight darkeningDarken
Use on outdoor furnitureNoNoYes
Use on indoor furnitureYesYesYes
Water protection rating2star3-star rating2-star rating

How Can You Waterproof Wood?

There are three main methods used to preserve wood for the long term by making it waterproof. One thing you should consider when deciding on the method to use is whether the wooden piece is located indoors or outdoors. The type of grain wood, whether light or dark, should also be used when deciding on this. These methods include;

Using Stain-Sealant Combos

Combos are especially great for large projects. It involves combining different stain sealants to achieve the desired color pigment and wood protection. Most of them come with binders such as water, oil, or alkyl bases. Using these combos is a short-term waterproofing option that requires reapplication at least once per year. They are also best used on interior furniture since they peel out when used on outdoor wooden surfaces, especially if they were not given ample time to dry off. 

Applying Sealants

 Some of these sealants include lacquer, urethane, and vanish. They come with the perfect waterproofing ability to protect your wooden furniture. Before applying them, you should ensure the wooden surfaces are cleaned and sanded. Give it time to cool and dry off and if the desired look and feel are not achieved, resand and recoat the wooden surface using your sealant. 

You can either brush or spray the surface, provided you do not shake the sealant before application. Shaking it causes the formation of air bubbles which may never disappear even after the sealant.  Bubbles can infiltrate water which could cause the wooden furniture piece to rot. 

Use Of Warm Hand-Rubbed Oil For Wood Finishing

The most common hand-rubbed oil finishes are Tung oil from Tung seeds and linseed oil. These two substances are used as the main ingredients for other oil finishes. They help enhance the look of wooden furniture while still playing a major role in protecting them from heat and moisture. Sometimes they are blended with other ingredients to enhance their drying time and eliminate their sticky nature. Tung oil and linseed oil are available in the market as pure products, and upon purchase, you can mix and customize them. 

Why is Engine Oil Not Good for Wood?

Engine oil is a commonly used lubricant for automotive engines, but it is not suitable for use on wood surfaces. Here are several reasons why using engine oil on wood is a bad idea:

  1. Degrades wood quality: Engine oil contains various additives and chemicals that can be harmful to wood. When applied to the surface of wood, these chemicals can degrade its quality, leading to discoloration, weakening, and deterioration of the wood.
  2. Unpleasant odor: Engine oil has a strong, unpleasant odor that can be difficult to eliminate, especially when applied to porous wood surfaces. The strong smell can persist for a long time, making the area unpleasant to be around.
  3. Stains and spots: Engine oil is thick and greasy, making it prone to leaving stains and spots on wood surfaces. These stains can be challenging to remove and may require extensive cleaning or even refinishing of the wood.
  4. Environmental concerns: Engine oil contains toxic substances such as heavy metals, petroleum hydrocarbons, and other contaminants that can harm the environment. Using engine oil on wood surfaces can lead to the contamination of soil, water, and air, posing a risk to plants, animals, and the ecosystem as a whole.
  5. Fire hazard: Engine oil is highly flammable. When applied to wood, it can increase the risk of fire. Even a small spark or flame can ignite the oil-soaked wood, resulting in a dangerous situation.
  6. Health risks: Engine oil contains toxic chemicals that can be harmful to human health. Direct contact with engine oil or inhalation of its fumes can cause skin irritation, respiratory problems, and even more severe health issues over time.
  7. Ineffectiveness in wood treatment: Engine oil is not formulated to treat or protect wood. Unlike specialized wood oils and finishes, engine oil does not penetrate the wood fibers or provide any protective properties. It may even hinder the effectiveness of proper wood treatments by sealing the surface and preventing proper absorption.


You can use old motor oil for wood protection despite it not being the best option. It does not dry out from the wood entirely, meaning it could remain soaked in the oil forever. You also cannot use it for indoor purposes as it could spill on the floor, especially when the wooden piece saturates in oil, creating a mess in the house. Motor oil has toxins making it hazardous to the environment and also to your health.