Most materials deteriorate over time, including finished lubricants. That is why knowing what to look for in lubricants, including their shelf life, is critical in determining whether they should be used again, discarded, or recycled.

Lubricant manufacturers recommend that you don’t use lubricants beyond their shelf life. Lubricating oils and greases deteriorate with time when in use or in storage. This can affect product performance which in turn can be detrimental to the equipment and costly.

In this article, we take a closer look at the estimated shelf life of finished lubricants, as well as optimal storage conditions.

Covered in this article:

How to identify expired lubricants
Storage conditions affecting all lubricants
Product shelf life
Recommended storage conditions

How to identify expired lubricants

The shelf life for lubricants is estimated and is based on the optimal storage conditions of these Lubricants within their original containers. After opening the container, use the leftover lubricant within one year.

Some easy ways to identify lubricants with an expired shelf life are a cloudy appearance, strong odour, an overly firm or dense consistency, a dark or hazy colour, and a slime-like appearance.

Storage conditions affecting all lubricants

Most materials – including lubricating oils and greases – deteriorate with time, which may affect product performance. The storage environment greatly affects the estimated shelf life of lubricants and greases.

These include:

Temperature

High heat (greater than 43°C) and extreme cold (less than -16°C) can affect lubricant stability. Heat will increase the rate of oil oxidation. Cold can result in wax and possible sediment formation.  

Light

Light may impact the colour and appearance of lubricants. Lubricants should be kept in the original metal or plastic containers they were packaged in. 

Water

Water will react with some lubricant additives. It can also promote microbial growth at the oil/water interface. Lubricants should be stored in a dry location, preferably inside.  

Particulate Contamination

Lubricant drums and pails should not be stored in areas where there is a high level of airborne particles. This is especially important when a partially used container is stored for later use. 

Atmospheric Contamination

Oxygen and carbon dioxide can react with lubricants and affect their viscosity and consistency. Keeping lubricant containers sealed until the product is needed is the best protection. 

Oil Separation (Greases)

Oil will naturally separate from most greases. Temperatures in excess of 43°C can accelerate oil separation.

Product shelf life

It is good to remember that shelf life and product service life are not the same. The latter refers to the product's lifecycle within its intended service – depending on the development and application.

The shelf life estimates are based on the assumption that the optimum storage conditions listed by the manufacturer are used. 

Past its shelf life

In certain instances, a product which exceeds its estimated shelf life may still be fit for sure. However, these products should be tested and evaluated against the original product manufactured specification. It is worth mentioning that product analysis and recertification come at a cost.

Recommended storage conditions

The first step towards achieving proactive maintenance of your lubricants, and ultimately your equipment, begins with proper in-plant storage and handling.

1. Store lubricating oils and greases in a cool dry indoor area, where airborne particles are at a minimum. Indoor storage also prevents label and container deterioration from exposure to weather.
2. If drums must be stored outside, use plastic covers or tip oil drums to direct water and contamination away from the bungs.
3. Always store greases upright to prevent oil separation.
4. Rotate inventory. Check the container fill date and use the oldest container first.
5. Keep containers tightly covered or closed to avoid contamination.
6. Wipe off the tops and edges of containers before opening them to avoid contamination.

Lubricants extend the life of equipment by lowering the need for maintenance and repair. The less maintenance machinery needs, the more affordable it is to run. So, it makes financial sense to choose the best lubricant for your needs and store it properly.

With this in mind, knowing what to look for when referencing lubricant shelf life is vital in deciding which lubricant is suitable for use or which should be recycled.