Not even certified yet, and 0.3 hrs on the engine (prop balance) and I have a small leak at the expansion tank sight gauge. I have a new tank assembly but don’t really want to remove the original unless I have to, hopefully in 5 years for a hose replacement. Has anyone replaced the crush washer (I assume that’s what’s behind the gauge) on their tank? I tried tightening it a little but don’t want to overdo it and crack the tank. The tank is sold as an assembly so I have no idea what’s behind the glass. Best case, I can use the gauge and washer off my new tank. I’m reluctant to remove them without assurance that I’m not breaking anything by doing so. Any insight appreciated.
Van's Air Force
The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!
Expansion tank sight gauge leak
- Thread starter SARLDO
- Start date
Where do you have a sight glass? Neither my expansion tank nor my overflow bottle have anything like what you're describing. I checked the Rotax illustrated parts catalog, and it doesn't show anything either.
The latest Rotax expansion tank has a sight glass. I've found it to be fairly worthless on the -12.
You might want to take a look at Rotax SB-912-080 "Inspection and/or replacement of expansion tank assy." In it they say "Due to a deviation in the manufacturing process, the individual components of the expansion tank assy. may not be sufficiently welded. Sealing of the assy. may be compromised and coolant leakage and subsequently an overheating of the engine may occur."
You might want to take a look at Rotax SB-912-080 "Inspection and/or replacement of expansion tank assy." In it they say "Due to a deviation in the manufacturing process, the individual components of the expansion tank assy. may not be sufficiently welded. Sealing of the assy. may be compromised and coolant leakage and subsequently an overheating of the engine may occur."
I did see that. Oddly enough, when I ordered a replacement tank, it came in the same configuration and I’m trying not to change it if I don’t need to. If that sight gauge is screwed in, I’ll remove it and try thread sealant. Otherwise, I’m going to replace.
