ROTAX Coolant Temperature

Phil Lockwood gave a Rotax 912 engine session at Sun N Fun. Rotax has a new cylinder head design which has more coolant capacity than the older Rotax 912 heads. My understanding is that with the old head design the injected version of the engine was boiling the coolant in the head. The head design was changed and instead of CHT the probes were relocated and changed to measure the coolant temperature. For the older engines Lockwood has a water temperature in line fitting (page 116 of the 2014-2015 catalog) and temperature sender that I bought and installed in my RV-12. You install the in line fitting between the outlet of the expansion tank and the radiator. I moved the CHT wire from the #2 cylinder to the temperature sensor installed on the in line fitting. Today was my first flight with the new set up. Left CHT is now coolant temperature and Right CHT is still CHT. Once airborne the coolant temperature is consistently about 20 deg higher than the Right CHT. From what I can tell from the new POH the CHT temperature (really coolant temperature) bands have not changed from the old values I have in my POH. Bob Kibby N712BK 242 hrs

The Dynon D-180 in the RV-12 has an unused thermocouple input on EMS pins 27 & 28.

Available Dynon D-180 thermocouple input

Thanks Joe. I'll wire my coolant sensor to that connection when I open up the instrument panel to install my NavWorx ADS-B. Before someone asks, no I haven't received my NavWorx unit. Bob Kibby