Sling Pilots Forum

The Rotax manual tells us normal operating oil temperatures are 190*-230*F. Unfortunately our TSi’s rarely operate in this range as the oil thermostat usually regulates the temps in the 160*-175*F range. Too low in my opinion. Therefore when the OAT is 60*F or below I add 1 7/8” blue painters tape as so:


I’m not sure that image will show up, but one strip all the way across both oil and coolant radiators adds about 20*F to both. Often the cruise oil temperature will go up to 190*-205*F…excellent running temperatures. If it’s a bit cold, I might add part of another strip across the radiators, or even tear a little bit out if the temps have risen a bit. Many people prefer to use the aluminum tape, which works well. Duct tape can easily fly off and Gorilla Tape leaves too much glue residue in my opinion.

The danger in adding tape is restricting cooling during the critical climb out phase, so I don’t use tape above the OAT of 60*F. Watch the EGT’s so they don’t go above 1700*, and I try not to go above 1695*F. Oil temps a little above 230* don’t hurt anything, but I back off at that point to keep below that temp. Coolant temps never seem to get into the yellow or red, but I often turn on the heater, blower and air vents to drop those temps about 5*F.

Good luck and experiment to see what works for you with your climate.

My IA neighbor (he works as contractor for the gov on a fleet of Piper Cubs and deals with cold WX ops) and I are devising a bowden cable hinged door to control the airflow over the radiator. He has a similar design on the cubs that works very well.

The radiator door is an excellent idea. Light Sport Aerotrek airplanes also have a large radiator with a manual door, and it works very well.

Any updates on this mod? OneAlphaMike on YouTube mentioned that he uses a tape as well. I am based in SoCal but it appears this would be helpful even in that region.

Has anyone installed a water thermostat to keep the coolant temperatures higher? I'm regularly flying in sub-freezing weather during the winter and the temps are very low, around 140-150 F. I'm not sure if an oil thermostat is an option, but I have read online about people installing water thermostats on other Rotax engines.