Letter Re: Motor Oil

Dear Editor and SurvivalBlog Readers:

I have a question about motor oil, because of an incident going back years ago when I had a discussion with a neighbor about changing oil in gas motor yard equipment, lawn motors in this case. I’ll never forget how the neighbor bragged how he never changes oil in his lawn mower. Year after year, it is pulled out in the spring with the old gas and old oil, and away they go. I’ll never forget hearing the screeching sound of that lawn mower motor seizing. Since then, I have heard numerous opinions on oil change schedules, and traditional oil versus synthetic oil. In contrast to the “never change the oil” thinking, I’ve talked to those who religiously change their oil every three months, even if the motor has never been started. With the recommendation of changing oil in a vehicle every three months or every 3,000 miles, whichever comes first, I go with the mileage and not the length of time, up to a year. But then synthetic oil changes everything. If I only put 3,000 miles on a vehicle a year and the recommendation is every 7,500 miles, should I keep it in for two years? And for lawn equipment, should I use synthetic oil in a 4-cycle lawn mower? If I do, should I change it every year, or can I keep it in there for the life of the mower/snowblower? Can I change back to organic oil after using synthetic oil? Can I mix them? I wonder that because I understand that some oil labeled “synthetic” isn’t; it is a mixture, explaining why it is less expensive. I think it would be very valuable to have these answers in the event of general scarcity of services and products. Maybe if everyone that I ask these questions didn’t come up with as many different answers, I wouldn’t be so confused. I am counting on there being an expert out there reading this who can give the definitive answer. I’m all ears. R.T.

HJL’s Comment: Most modern motor oils far exceed the service levels required of them in practically all engines. The motor oil, synthetic, natural, or blends are not changed out because they are beginning to break down; they are changed out because they are dirty. The standard oil filter is required to have enough flow through it so that all parts of the engine requiring lubrication can have an adequate supply. That means that if the filter is built to a practical size, it can only filter down to about 20 microns. A 20 micron particle is still large enough to enhance wear and tear on an engine. The Aero industry has long dealt with this issue by using a bypass filtration setup where approximately 10% of the oil is sent to a bypass filter that is capable of filtering down to 2 microns. Over the course of a couple of minutes, all of the oil in the lubrication system will make its way through this filter, effectively giving you a system that delivers the volume and rate of a 20 micron filter but the effective filtering of a 2 micron filter. Since you have now removed the most common issue (dirty oil), your oil can certainly last a lot longer.

I currently use Amsoil’s Universal Dual Remote Bypass System on my truck. In concert with a good synthetic oil, like Amsoil’s Signature Series, you end up with an oil system that can easily make it to 60,000 miles or 1000 hours of operation. In my case, I don’t put that many miles/hours on the system, so I end up changing the oil once a year just to be safe. (There are other considerations, such as moisture contamination, et cetera.)

You should be aware that most car manufacturers don’t care how much you love your care or how good the oil filtration system is. If you don’t change oil on their recommended schedule, you run the risk of violating the terms of their warranty.