I have been using Mobil 1 for a few years now and I just read that it may not have the lubricants that keep the seals soft in the engine. They say that if I were to go back to regular oil my seals might swell up and crack. Is there any truth to this statement? The engine has 260,00 miles.

 

I've never heard that synthetic oil hardens the seals, although I haven't used it before. That's probably only true when the car is brand new. If you get a new car, you have to use regular oil in order to break it in, then you can switch to synthetic.

Also, you really shouldn't be running synthetic with an engine that has that many miles. Mine doesn't even have half that many miles and I only put in regular oil. The synthetic oil is a lot thinner and can get through your seals and small cracks where regular oil wouldn't, that's why they don't recommend using it on higher mileage engines. You might want to try Valvoline Max Life. It's a regular oil that is specially formulated for higher mileage engines in order to condition the seals.

Synthetic oil may be slightly better than conventional motor oil in terms of its durability and lubrication, but it's really not worth the extra money, even for a new car. I mean, the engines that are being made today are so durable, that even running on conventional oil they will outlast most of the other parts on the car. And the extra 1 mile per gallon that you may get out of synthetic really doesn't offset the extra cost of the oil and there really isn't any gain in performance from using synthetic. There's just a lot of hype in the industry in order to make a large profit from the sell of synthetic oil.

-C-