Check the oil level every time you fill up with fuel. You’ll find that every 3rd fill-up or so that it is necessary to add about 1/2 a quart of oil. THIS IS NORMAL. The rotary engine utilizes a metering system that draws a small amount of oil out of the oil pan and then feeds it into the engine with the air/fuel mixture to lubricate the apex seals. This oil is not retrieved but is burned with the air/fuel mix and then expelled out the exhaust.
However, just because the oil is replenished in this manner does not mean that you can get away with never changing the oil. In fact, it is wise to change the oil and oil filter every 3000 to 5000 miles (5000 to 8000 km) at the very least. Spring for the extra couple of bucks for a decent oil filter too. Purolator, AC Delco and Wix are good filters. The cheaper ones by Fram and Champion will usually do the job, but have been known to fail and allow bits of cardboard and glue to float around in engines and plug vital oil passages. Engines have failed because of this. True, the odds of you getting one that’s this bad are less than one in 20 but why chance it?
Oil grade and type:
Mazda’s owners’ manual recommends 20W50 non-synthetic multigrade, but unless you live in an area where the outside air temps rarely drop below 70F it’s best to use 10W30. If you live in places where the winter temps go below 0F you may want to go with 5W30 during those months.
There is an ongoing debate over whether synthetic oil should or should not be used in a rotary engine. One side of the argument says that synthetic doesn’t burn as clean when ingested by the engine via the oil metering system and should therefore never be used, while the other side claims that newer synthetics are ok and provide better protection. If you are running pre-mix (pre-mix = small amount of 2-cycle oil mixed with fuel, accompanied by removing the metering system) this argument becomes a moot point since the apex seals are no longer being lubed by engine oil from the pan. Otherwise, the non-synthetic engine oil does an excellent job and costs about 1/3rd as much as synthetic. That’s what I use.
Low-cost Engine Longevity
I know I lost a few of you with …