The Bushcaddy ELSA with Rotax 912 ULS I co-own had a problem awhile back where the CHT got too hot and a piston disintegrated on takeoff. Since the repair we've replaced the oil cooler with a larger one, modified the cowl intake opening for the oil cooler to give the air a straight shot and sealed all around the radiator and oil cooler to force all air thru them and eliminate any air going around. For most of the year the thing runs so cold we have to put lots of tape on both rad and oil cooler just to get to the bottom of the green. Now that we've had a few warmer days we are seeing the CHT's continue to rise up to 245 F on extended climb in OAT of 85 F or more, but oil temp will stay at about 180-190 and the highest coolant temp I've seen is 205 f, and usually no more than 200 even as the CHT is way up there. The CHT's are about the same on both sides, maybe 2 degrees hotter on the right side.
Our Coolant gauge is on the tube after it flows out of the engine. We use Prestone Dex 50/50 pre-mix coolant with a bit of Redline Water Wetter added. It was put in about 9 months ago. The coolant tank is full and there are no kinks in the coolant hoses. One of us did put the rad cap on once with the gasket folded back on itself but we straightened that out and it seems normal and does not leak. The engine is cowled but does not have the Rotax fiberglass shroud around the cylinders. There are no coolant leaks.
I have the redline for the CHT marked at 249 F on the VDO analog gauge. Is that correct? And if so, why would the coolant be nice and normal while the CHT's are so close to redline? We are having to really keep an eye on this and level out and circle around when trying to climb over the mountains. Much of the summer we will be seeing temps over 100 degrees at the airport (SZP) where the airplane is based, so this is just going to get worse. I'd hate to lose a piston while crossing the mountains. Any suggestions?
Our Coolant gauge is on the tube after it flows out of the engine. We use Prestone Dex 50/50 pre-mix coolant with a bit of Redline Water Wetter added. It was put in about 9 months ago. The coolant tank is full and there are no kinks in the coolant hoses. One of us did put the rad cap on once with the gasket folded back on itself but we straightened that out and it seems normal and does not leak. The engine is cowled but does not have the Rotax fiberglass shroud around the cylinders. There are no coolant leaks.
I have the redline for the CHT marked at 249 F on the VDO analog gauge. Is that correct? And if so, why would the coolant be nice and normal while the CHT's are so close to redline? We are having to really keep an eye on this and level out and circle around when trying to climb over the mountains. Much of the summer we will be seeing temps over 100 degrees at the airport (SZP) where the airplane is based, so this is just going to get worse. I'd hate to lose a piston while crossing the mountains. Any suggestions?
