Should synthetic oil be used in older cars?

Many owners want to know this: should they use synthetic oil in their cars or not? community member Sujith Hedge put this question to the community recently. “My car Wagon R (2005 December vintage) has clocked 45,000 km and is in excellent condition. After reading your exceptionally good article “Guide to car engine oils: Mineral oil vs Synthetic oil”, I am confused. Should I use synthetic oil in my 8-year old car—your article suggests synthetic oils aren’t good for older cars?

Simple answer is, yes you can expert Shreyans Jain uses synthetic oil for his 2.5 lakh kilometre-old Wagon R. “It is not about the age of the engine it terms of years or km but its internal condition. If the internal parts are worn then the sludge and dirt effectively act as seals and keep the engine together. My Wagon R has clocked 2.5L km and I have been using Castrol Magnatec 10W 40 for the past 3-4 years. You can safely use synthetics as you say your engine is in excellent condition. This will only increase its life and make it a bit smoother too.”

“Synthetic oils have better properties than mineral oils, which is why they are the de facto choice for high performance cars or for usage under extreme conditions. It has got nothing to do with engine capacity. The better lubrication and thermal stability only improves the life of the engine components. The only real problem is the cost, which is 3 to 5 times more than regular mineral oils. So it does become a bit tricky to actually justify paying the extra premium for use in stock small cars, for the benefits will be evident after many long years of running, when the engine won’t give away.”

You shouldn’t only if your car is really-really old expert Roshun Povaiah has this to say: “Older cars means cars that are manufactured pre-1990 or so, when engine tolerances were not as good as the modern engines in cars. These cars (especially cars that had push-rods and not overhead camshafts) – such as the Amby or Premier Padmini etc, were actually better off using mineral oils as the oil seals in the engine were not that great and synthetic oil would tend to leak out or even dislodge some thickened seals (and sludge) which would lead to bigger problems. In most modern cars, Marutis, Hyundais etc, you should have no problem switching to synthetic. Just drain, flush, change filter and top up.”


So there you have it: No problem using synthetic oil in older cars as long as they are reasonably well maintained.