General Care and Feeding of the

Mazda Wankel Rotary engine

specifically in extreme heat of the

American Southwest Deserts

recommendations from 30+ years of servicing and racing

the rotary engine in southern Arizona


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- The round engine does require a different level of care -

These are recommendations for extreme conditions

but will not hurt those driven under more normally conditions


Be kind to your rotary and it will reward you with many trouble free miles of outstanding performance and reliability. The heart of your rotary powered Mazda the NSU Wankel 12A/13B is unsurpassed by any conventional reciprocating engine. However, this will not come about without you being a thoughtful owner since the service and maintenance of the rotary engine is more important than that of conventionally powered vehicles. 

The conditions we drive under in the southwest are extremely hard on the rotary engine. Road surface temperatures can reach temperatures of 140/200F it is not uncommon to see melting asphalt in the summer. Under hood temperatures can reach 400F. Exhaust temps as high as 1800F. These conditions can cause rapid breakdown of your rotary's vital fluids; the oil and coolant.

It is essential to keep these fluids cool and clean. Engine oil and coolant, the life's blood of the rotary engine, must be checked and changed often to remain efficient as lubricating and cooling agents. 

Engine oil acts as not only the lubricating agent but almost more important as a cooling agent. Which is why it is so important to keep the oil coolers in good condition making sure that the cooler fins are not damaged, very common issues with the FD3S and FE3S platforms. Most of you  know that the rotary uses engine oil to lubricate the internal seals on the rotor: apex, corner, side seals and rotor housing surfaces. This oil comes from the oil pan. If the oil is not clean the suspended dirt and contamination are injected into the combustion chamber this will result in premature wear of the internal components. Generally dirt has not been proven to be a good lubricant.

Oil consumption via the metering system in the early, pre 1979, Mazda's was a quart in 800miles. This did have consequences in that many owners did not check oil level and add a quart every other fill up. That is another story. In the next generation rotary, 1979/1985, the metering system oil was lowered to a quart in 1200/1500 miles. 1986/1991 was leaned to 1500/2500 miles. 1993/1995(us import) 2500/3500 miles. And the Renesis Rotary 1 quart in 3/5000 miles. Early Renesis (2004) have issues with the metering system which Mazda has corrected to improve the oiling for this particular design rotary.  Unfortunately leaning out the metering oil does take a toll on the long term reliability. Making it even more important to keep the oil in clean condition.

If properly maintained, your rotary can last in excess of 200,000 miles. If not, premature failures can occur in less than 40,000 miles. With replacement costs now reaching the $5000/$8000 range $35/$45 for an oil change every 3,000 miles for normally aspirated 1,500 miles for turbo applications is cheap insurance. Recommendations for oil are any top grade SE/SF oil, I have used Castrol GTX exclusively since the late 79's. For the extreme heat I use, 20/50 for early engines, 30w for turbos, 10/50 for Renesis, cooler climates can use the lighter weights.

Synthetic engine oils must never be used in a rotary engine that is equipped with a functioning oil metering system. This is due to the fact that synthetic oil does not mix with fuel and does not act as a lubricating agent in the combustion chamber. Some synthetics actually form silica like deposits on the rotors. The only time synthetics can be used is in engines where the metering system has been removed or disabled usually for race applications where pre-mix is used to give the precise mix needed for race engines.

Maintenance of the cooling system is important also. Mazda recommends a 50/50 mix. Unfortunately this mix is not optimum protection for extreme heat operation. Straight water actually is the best cooling medium especially when used with Redline Water Wetter treatment. Ethylene glycol's function is to keep the water from freezing and usually has some chemicals for corrosion protection, which Redline WW also contains. When it comes to the water, do not use tap water, purified water only, if you will not drink it it should not go in a rotary radiator. The cooling medium should be tested regularly and changed every year or two.

Do not let anyone try to talk you into using more that 50% or straight ethyl glycol, that is a guarantee to overheating issues, this is not only for round engines.

In conclusion:  change oil with quality oil when it changes color use only Mazda oil filters, check and change coolant every year or two, otherwise maintain by Mazda recommended service intervals found in your owner's manual. Make sure the oil cooler fins are straight on the later model platforms, 3rd generation RX7's and RX8's.

Do this and you will be rewarded with a happy rotary engine.

Do not forget to drive them they way they are meant to be driven.. spirited.



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Rx for your 7

Tucson, Arizona 85716

  "piston engine goes..."

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12 November 2010 11:25 -0500

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