Rotax four stroke aircraft engines have proven themselves as reliable pieces of machinery. They can be bought as experimental (UL) or certified (A and F) engine and there are four main models (injected too) to date. The original engine is the 80 hp 912, from which the 100 hp 912S was developed and Rotax also has a 115 hp turbocharged 914 engine. In 2015 Rotax announced the 135 hp fuel injected turbocharged 915iS.
Rotax released two service bulletins regarding coolant and the use of waterless coolant. The article below describes the use of Evans Waterless coolant in Rotax 912 and 914 engines.
Waterless Coolant from Evans.
Excerpt from the document:
The 9-series engines come from the Rotax factory with two VDO cylinder head temperature (CHT) probes. One is located in cylinder No. 2 and one in cylinder No. 3. Monitor the hotter of the two cylinders in your installation. The normal CHT range should be between 167°F and 230°F. This is new information. In the past Rotax only gave a maximum temperature, redline, of 300°F for the 912 and 275°F for the 912S and 914.
These maximum temperatures remain unchanged provided you make the switch to Evans waterless coolant. There is no alternative; it’s Evans NPG+ or Evans NPG+. End of discussion.
To continue reading see the pdf below: