Engine oil is vital to keeping an engine lubricated and functioning correctly. In a car that is due to be parked for a long time without use, it is right to question how long the oil will last and whether it will be safe to use when I come to drive the car again.
Engine oil has a shelf life, usually printed on the oil bottle. It is correct to assume that the oil still has use if it is still within its bottle expiration date. But how will you know the age of the oil if it’s in the engine? Well, it’s pretty straightforward to tell if the oil is still fit for purpose just by looking at the condition. More on that later in this article.
Does Engine Oil Go Bad?
In short, yes, engine oil goes bad. Over time, engine oil in a bottle on the shelf degrades, the properties and additives in the oil become redundant, rendering the oil useless before it’s even poured into an engine.
Oil degrades much quicker in an engine; it is exposed to carbon contaminates, moisture, and, in some cases, fuel, which means it becomes less dense.
Engine oil is a thick fluid that doesn’t flow very quickly when cold. When warm in a running engine, it flows more freely, properly lubricating the engine. Engine components will overheat, seize, and eventually fail without proper lubrication. Old engine oil that has lost some density will not lubricate engine components correctly. Equally, engine oil that is too thick and becomes like treacle will have a similar effect, although this doesn’t usually happen with oil sat for long periods.
How Long Does Oil Last in a Car Not Driven?
When a car is not driven, engine oil will last for about 12 months. If the engine oil were new before the vehicle was parked for an extended period, it would last much longer, even up to its expiration date printed on the bottle. You may think great; this bottle has another five years left. However, the degradation process when the oil is in an engine is much faster than in a sealed bottle. It is almost impossible to tell if the oil properties have degraded without using technology found in laboratories, but you can take an educated guess by looking at it (keep reading on).
Most car manufacturers recommend changing engine oil around 8 – 10,000 miles or 6 – 12 months, depending on the type and amount of driving you do. Although the engine oil can last 12 months without problems, if the car is not moved for 6 – 12 months, it is recommended that you replace the oil before using the vehicle again. Replacing the engine oil will prevent further issues later.
How Can You Tell if Engine Oil Is No Good?
There are some easy ways to determine if your car’s engine oil is still in good condition. Firstly, take out the dipstick and wipe it clean. Then, reinsert the dipstick and check the oil level. If the oil on the dipstick is a clear brown color and you have some fresh oil on hand, you can compare the thickness and color by letting a small amount drip onto a rag. If the fresh oil is similar in thickness and color to the oil on the dipstick, you can assume that your engine oil is still in good condition. However, if the oil on the dipstick is dark brown or black and thick like treacle, it needs replacing.
The other issue that can happen when a car sits for some time is the oil will become low; this could be because of a minor oil leak. As the oil will have been exposed to moisture through the leak, replacing it rather than topping it back up will ensure you get rid of any poor-quality oil.
What Happens if You Drive a Car With Old Oil?
There are several issues associated with driving a car with old, degraded oil. The most important issue is that the oil will no longer be able to perform its job effectively. When the oil loses its properties, it will no longer be able to lubricate and stick to the necessary components. Due to contamination and burnt carbon, the oil thickens, which means it can no longer lubricate the parts. The thickened oil can make it difficult for the engine to run smoothly, decreasing performance, fuel economy, etc. This could eventually lead to engine seizure and failure.
In addition, degraded oil loses its ability to cool the internal engine components, which can cause it to burn and emit a pungent smell. Essentially, driving a car with old oil that has not been replaced for over 12 months could pose severe risks to the engine.
Summary
To answer the question of how long does oil last in a car that is not driven? It is approximately 6 to 12 months. If you check the condition of the oil by looking at it, you will be able to confirm if it has expired. It is no good if it no longer resembles new engine oil. The only thing you can do with bad oil is to replace it. It’s not worth the risk of driving with old engine oil, as it can cause problems. A quick and affordable oil change can prevent costly damage.
