Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
I do not add petroleum based oil.
I will try either Vaseline (petroleum jelly) or vegetable oil. A couple of drops of vegetable oil is nothing in a tank, and the petroleum jelly tends to stay where I place it.
If the problem is a worn shaft, though, this is only a little bit of help, very short term.
When you have cleaned and reassembled it all, then put it on the tank...
Does the end of the intake touch the inside of the tank? Or do you have anything over the end (perhaps a sponge filter) that might touch the back of the tank? If so, then this might be pushing the intake tube just a tiny bit out of alignment. Not enough to stop it running, but enough to make this noise.
Next suggestion: It is possible to take these filters all the way apart, unscrewing the motor from the rest of it, and cleaning a few places that are not as easily cleaned from above. As you reassemble it, put a drop of vegetable oil or a thin smear of petroleum jelly on the O-ring. This will make it slide back into place easier, and ensure a better seal.