Motor Oil Myths or Facts


We receive calls from customers who have ‘read something on the internet’ or ‘heard something somewhere,’ pointing to a lack of facts about motor oil. There are ‘armchair tribologists’ who, although well-intentioned, spread myths about motor oils.

Myth 1: Engine oil must be replaced as soon as it turns black.

Fact: not necessarily. In many diesel applications, the oil can turn black immediately after changing. Detergent and dispersant additives keep contaminants in suspension, preventing them from sticking to engine parts, which can cause the oil to turn black. Engine oil turning black can be a sign that the additives are doing their job. If you truly want to assess the oil’s condition, a used oil analysis will precisely indicate when the oil needs to be changed. This is usually not visually discernible. Here is a post explaining why engine oil turns black and whether it indicates the need for a change.

Myth 2: You must change the oil every 4,800 km.

Fact: This myth originated many years ago from quickly lubricating chains to ensure customers keep coming back. Some oils were of low quality when this myth began; however, nowadays engine oil and engine technology have become much more advanced. Original Equipment Manufacturers (OEMs) now recommend much longer oil change intervals, some up to 16,000 km or more. Solution Oil can last up to 40,000 km or a year.

Myth 3: You cannot mix synthetic and conventional oil.

Fact: Conventional and synthetic motor oils have the same basic components: base oils and additives. Although base oils and additives in synthetic oil are superior to their conventional counterparts, they can be safely mixed. Many years ago, some oil companies introduced synthetic motor oils that were NOT compatible with conventional oils, but they were quickly removed from the market: this caused issues when a customer had to add a liter of oil. Therefore, nowadays synthetic and conventional oils can be mixed. However, remember that when mixing the two, the lower-quality oil will limit the performance to that of conventional oil.

Myth 4: Once you switch to synthetic oil, you cannot go back.

Fact: Since the two oils are compatible, it is entirely safe to switch back. The question we have is why? Why would you switch back after using a synthetic motor oil with enhanced benefits and performance criteria?

Mythe 5: Synthetic motor oil causes engine oil leaks.

Fact: In summary, synthetic oil can identify a leak but not create one. Engines that are not properly maintained may have cracked and worn seals with sludge and deposits masking the worn or broken seals. Enhanced detergents in synthetic substances can sometimes remove these “false seals” of dirt and sludge, exposing the worn seals. A good synthetic oil, such as Solution Oil, conditions seals to keep them supple and prevent leaks. Solution: use high-quality synthetic motor oil before the seals reach that state.