- Can you use synthetic oil in old cars?
Whether your car is 30 years old or a classic, there is synthetic oil available for it. The easiest way of knowing this is to look at the manufacturer’s recommendation. Synthetic oils are not new; they have been around for commercial use since the 1970s. One digression is to figure out where the idea came from that you cannot use synthetic oils for older cars. Ultimately it comes from bad experiences in the past. Early synthetic engine oils were ester-based. Some engine seals are also ester-based, and there is compatibility there. Ester can cause swelling of engine seals, and a little bit can actually be a good thing. But if the ester concentration of the oil is too high, you will see excessive swelling in the seals, a drop in the hardness along a loss in tensile strength. If you are a car owner you will want the engine seals to retain their properties regardless of what the engine is doing. You don’t want the seal to get brittle and lose strength. With some early synthetic motor oils using formulations not used today, this is exactly what happened. The oil was not super compatible with the engine seal, so you would have found oil leaking all over the driveway. So how do we know modern synthetic engine oils won’t damage engine seals? There is a lot of testing going on at the manufacturers to ensure that that kind of thing does not happen, which is why this is no longer a problem. Today, if you look at the back of a bottle of oil, you will see the API certification, the ILSAC certification, and the manufacturer’s certifications. These certifications have extensive testing going on before the synthetic oil is released to the market and they also have seal compatibility testing done. If your synthetic engine oil has the right certifications, you will not have to worry about the state of the engine seals at all, so running a synthetic is not a problem at all.
- Can synthetic oils cause leaks in old cars?
There is an idea often perpetuated that synthetic oils have more cleaning power and will remove sludge and gunk within your engine, exposing leaks and causing the engine to leak oil. This is the wrong approach towards the longevity of the engine. It’s true that synthetics have higher concentrations of dispersants and detergence, and other cleaning elements, but cleaning your engine is never a bad thing. Certainly, if you have sludge and gunk building up, it is bad for your engine. The sludge can end up blocking the oil drain holes and consequently lead to more sludge formation. As a result, the engine will get more heated and eventually fail. If your engine has a leak then it’s obviously a problem and most probably it is a failed engine seal that is the problem. However sludge and gunk building up around that seal is not a solution, it is just another problem. Using sludge as a solution will be like causing your engine to fail sooner so that it does not leak oil. This, obviously is no solution at all.
- Should you use thicker oil if your car is consuming more oil?
What about old engines that are burning or consuming a lot of oil? In this case, should you consider using thicker oil? Actually, it might not be a bad idea. As a general rule, you should always use the viscosity that your car manufacturer recommends. But as we all know, engines do not last forever. Wear and tear happen and as we have the wear occurring, it can change the clearances within an engine. For example, if you have an old car with a lot of miles on it, and when you are sitting idle when you have relatively low oil pressure, the oil pressure light comes on or maybe flickers. This is most often due to the oil pressure being normal and suited for the engine, but with age, the clearances within the engine have increased, there is more space, and the oil is now too thin for maintaining pressure in the wider areas. So in this case, using thicker oil can prolong the life of the engine. The lesson here is that you should not proactively switch to a thicker grade engine oil if there are no signs of your car being sold or worn out. Bumping up an oil grade should be thought of as a last-ditch effort to prolong the life of the engine. The thicker oil can help, but it will not change the fact that your engine is on its way out in some time. Higher viscosity oils will tend to have lower volatility which means less of the oil burns off over time.
- When should you consider using high mileage oil?
High mileage oils seek to be a solution for those cars whose engines have started to wear and might be burning excessive oil, or leaking oil. There are a couple of differences between standard synthetic oil and high mileage oil. High mileage oils have a seal swelling agent which serves the purpose of reconditioning engine seals. The seal swelling agent will recondition the seal, ensuring less engine oil makes its way past the seal. This does not mean that the seal is permanently fixed. If your engine’s issue is a broken seal, then the right solution for it would be a new seal. High mileage engine oil can help to prolong the seal’s useful life if it has started to deteriorate. That said, using high mileage engine oil will not harm your car’s engine as long as the oil meets all the industry specifications. Another difference of high mileage oil is that it uses base oil with a heavier mixture. This slightly higher viscosity means that the oil has lower volatility and does not turn into a gas, burning within the engine. It is important to understand why your engine is burning more oil than usual. Simply put, old engines will start to experience problems with time. High mileage engine oil cannot reverse engine wear, but it can help recondition engine seals and help cut down on oil consumption. To summarize, you can use synthetic oils in old engines and it will not cause a leak like some of the early products on the market.