Is fully-synthetic engine oil a no-go for older cars? Let's put this matter to bed, shall we?

Alright, let's talk about something as thrilling as engine oil. We have choices - mineral, semi-synthetic, and the fully-synthetic oil. Most people agree that fully-synthetic is the way to go. But, when it comes to older cars, there's a debate on whether fully-synthetic is the best option. Now, why's that? Let's dive in.

Synthetic oil 101

So, fully-synthetic oil is a bit fancy. It's got a more consistent molecule size and can go the distance. But, here's the thing - older cars sometimes don't seem to get along with it. They start leaking. Why? Because the chemical makeup of a fully-synthetic oil might not be compatible as it might not work well with the seals in your old engine.

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Compatibility check

Engines seals have a tough job. They need to handle high temperatures and pressures without breaking down. But, when they don't get along with the additives in fully-synthetic oil, things get messy. The seals might become too soft or swell up. It's not their fault, really. It's just a matter of not being on the same page as the newer oil. 

Note: Additives refers to a specialized chemicals that are mixed into the fully-synthetic oil to enhance its performance. These additives improves lubrication, reduces friction, prevents corrosion and maintains engine's cleanliness.

When we say the seals in an older engine "don't get along" with these additives, it means that the chemicals in the fully-synthetic oil may react in a way that affects the integrity of the seals. This reaction can lead to the seals becoming too soft or expands too much. This can result in leaks or other issues, causing a mess in the engine. Got it?

Detergent in additives

Fully-synthetic oils come with detergent additives. These means like you have your own cleaning crew for your engine. They go in and sweep out the dirt and excesses. Great for cleanliness, not so great for old engines with leaks. They might end up exposing existing problems. 

So, is fully-synthetic oil a bad guy?

Nah, not really. It's got its perks (except if you're a rotary engine). It's consistent and lasts longer. But, for older cars, it might be a bit too much. If your car is so old, that its first GPS was a fold-out map, maybe stick with mineral or semi-synthetic oil. They'll get along just fine.

Note: Rotary engines are a type of internal combustion engine that work on a different principle than the traditional piston engines. They have a unique design and operates using a spinning rotor rather than pistons. Because of this design, rotary engines have different lubrication requirements compared to piston engines.

Notable rotary engined car: The Mazda RX-7 

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The old hag..sorry. The old car experience

If you've got a classic car in the in the workshop now, you're probably burning a hole in your pocket to overhaul its engine. While you're at it, why don't you go ahead and invest on new seals and pair them up with compatible engine oil - the fully-synthetic oil. Because new seals can work well with fully-synthetic oil. It's worth it!

                                                          Photo: carfromjapan.com

The golden rule: Compatibility is key

Whether it's mineral or synthetic, make sure it is compatible with your seals. Some oils and additives just don't get along with certain seal materials. 

So, there you have it - a crash course on engine oil compatibility. It's not about being fancy, it's about finding the right fit. It doesn't matter if your car was made in the time when the dead sea was just sick, there's an oil out there that'll keep it going. Happy driving!

Peace out.