On June 15, 1957, the city of Tulsa, Okla. buried a new gold and white 1957 Plymouth Belvedere Sport Coupe in a purportedly watertight vault in downtown Tulsa as part of Golden Jubilee Week, a celebration of Oklahoma’s 50th year of statehood.  Before the car was buried, citizens were asked to guess the population of Tulsa in the year 2007 with the promise that whoever turned out to have the closest guess would be awarded the Belvedere at Oklahoma’s Centennial celebration in 2007.  The entries were sealed and buried inside the vault with this mint condition top-of-the-line Chrysler.

One Tulsan standing in the crowd that day was Ted Baxter, whose image appeared in the Belvedere’s then famous Life magazine photo. “Not a year has gone by I haven’t thought about this car and event. I have wondered many times why it made such an impact on me, a question I still can’t answer.” Six year old Ted was not alone. “I couldn’t understand why they were going to bury it for someone to dig up 50 years in the future. That seemed like an amazingly long time. My brother told me that it would be in the next century. ‘What’s a century I asked?’” 

The 1957 Plymouth Belvedere as it was lifted from the vault in which it was buried in 1957.

Unfortunately, as Robert Burns once observed, the best laid plans of mice and men often go awry. In this case, the theoretically watertight vault failed in its mission.  Two days before Sleeping Beauty was to be excavated, workers unearthing the Belvedere were shocked at what they found when they removed the cover of the 12 x 22 foot vault. Several feet of mucky water had seeped in. Though shrouded in protective plastic, the evidence of potential disaster presented itself to an array of onlookers who stood aghast at the sight. Some even wept.

There were many lessons learned that week. One was that we now know what happens when you bury a Plymouth Belvedere for 50 years.

There were other contents in the car worth commenting on including a case of beer, for example. Beneath the rust one could still read the word Schlitz on most of the cans. We know from Budweiser’s “Born On Date” ad campaign that beer does not last forever, that this was probably skunky beer.

Because there was no certainty in 1957 that cars would run on gasoline in the 21st century, the good people of Tulsa also placed a large container of gasoline and some motor oil in the trunk of the car. It is this latter item that brings me to the crux of this article. What is the shelf life of motor oil? Would it be safe to put 50 year old motor oil in a car, even if the car were 50 years old?

Well, the answer to that question depends on who you ask. Shelf life recommendations for lubricants can vary significantly, from a year to a century, depending on a range of variables. The primary issue is storage environment. Not all motor oils are stored under ideal conditions. Here is a short list of factors that can influence the shelf life of motor oils.

Product Design.  Some formulation chemistries and certain additives are more aggressive than others. The nature of the chemistry can affect the shelf life of lubricants.

Storage Temperature. Both high heat (greater than 100ºF) and extreme cold (lower than 0ºF) can affect lubricant stability. Decreasing the storage temperature can cause sediment formation and additive separation. The ideal storage temperature should be between 45ºF and 80ºF.

Moisture. Water can react with additives in the lubricants to form insoluble materials and shorten the shelf life. Water can also promote microbial growth in lubricants. If water gets into the container through improper handling or condensation, condensation can occur when the storage temperatures fluctuate over a wide temperature range.

Contamination.  Elements such as iron and copper in the oil can catalyze the lubricant oxidation process and shorten its shelf life. These elements can be introduced to the lubricant by improper handling, storage and use of equipment.

Frequent Agitation. Frequent agitation of an open lubricant container can incorporate air into the oil. Oxygen can react with lubricants and affect their viscosity and consistency. Agitation also serves to emulsify water into oil and increases the rate of lubricant degradation.

The optimum storage environment for motor oils and other lubricants are as follow.
1. Store lubricants in a cool, clean and dry indoor area.
2. The ideal storage temperature is between 45ºF and 80ºF and at a temperature that does not fluctuate significantly.
3. When storing drums or other large containers outside for extended periods of time, ensure that no dust or moisture enters the container.
4. Grease containers should be stored right side up due to bleeding (fluid separation). Bleeding commonly occurs with grease and is more prominent at higher temperatures.
5. Wipe off the tops and edges of containers before opening to avoid any contamination from improper handling.
6. Always use clean tools. Common signs of improper storage or contamination of a lubricant may include:
            • Layering within the fluid
            • Formation of solid particles
            • Color change or hazy appearance

A team of mechanics led by American Hot Rodder’s Boyd Coddington attempts to open the hood in order to assess whether the car could be started. As was feared, it was a rusty hulk inside and out.

If any of the above conditions exist, the lubricant may have become contaminated or its shelf life may have been exceeded. In any case it is advised to dispose of the product properly. In some instances a lubricant can be tested to determine its serviceability. If the product’s test results fall within the original specifications, it should be suitable for use.

One more thing to check. You’ll want to validate the product’s performance claims against the current OEM specifications. Equipment design and specification changes over time can make the old product obsolete for new equipment. The current API spec motor oils is SM and for 2007 diesel vehicles it is CJ-4. 

Bottom line, there are a lot of variables to consider, but generally, under ideal storage conditions the estimated product shelf life for AMSOIL lubricants can be quite long, with five years being a guideline. Care should be exercised when using lubricants that have been stored for a long time.

In the meantime, synthetic motor oils are only recommended for vehicles with mechanically sound engines. This would pretty much eliminate 1957 Belvederes which have been buried and soaking in water for a few decades or more