Burst of overflow tank 912
After a short flight yesterday, I got back to parking and ran couple of electric test at low RPM on my 100hp 912 rotax. At some point, I heard a large burst followed by a lot of white smoke coming from the engine. I followed the emergency procedures and quickly realized that something wrong happened with the fluid cooling system as the ground was filled with coolant. This was confirmed later on as the overflow tank appeared to have burst from the interior on one of its bottom corners.
Our mechanic will have a look at what exactly happened, but I was wondering if anyone had clues into what could have happened. For context, I never had overheating issues in the past, and the day of the incident the weather was not hot (low 70F), and I kept the RPM well within the green, for just couples of minutes.
Having read about the 912 cooling system, my initial assumption is that the cooling pump stopped working, the engine overheated, and the expansion valve sent more water to the overflow tank than it could handle.
Any thoughts or ideas?
Thanks!