I just finished fixing a small leak on my C-172, the gasket under the generator was dripping just enough to make a mess so when I chnaged the oil I pulled the generator and replaced the gasket. The old gasket was glued on with silicone on both sides, so I did the same to the new gasket. After filling the engine with oil, test run and leak checking, etc. I realized there is a 3/8" hole and a small "drain chanell" in the case under the gasket at the top of the generater opening. The old gasket had this drain hole and chanell sealed off, and my new gasket also has this sealed off with silicone. Does anyone know
1: what this hole and drain chanell is for?
2: could having this hole blocked off have caused the leak under the generater gasket?
3: Is there any danger of continuing to run the engine with this hole blocked off?
I'd rather not pull the cowling and generater again if I don't have to, but I certainly don't want to risk damaging my engine.

It's been a while since I sold my C170,but as I recall the generator gasket is a one-piece affair which also incorporates the tach drive gasket. I was told that they shouldn't be cut, in other words to replace the complete gasket, but I did cut mine & replace only the generator portion & it seemed to work OK. Maybe the tach drive portion is leaking?

Dale,
The hole and channel are to allow a path for oil to escape in case the generator seal starts leaking. They should be kept clear.
Cheers,
Tom