What is service life of Eheim 1048 impeller?
 

Mine's got a slight rattle. I'm not sure if it's the pump or perhaps it's pressure related and the jets on my cascade need cleaning.
I think this pump has seen over 2 years of continuous 24-7 use.

New impeller assemblies are around 7 bucks online.

Drat. Shaft/bushing kits are only $4....but $8 to ship. Gotta love shopping on the intarweb.

I replaced the whole impeller assembly and what a difference...there was quite a bit of play. It's dead quiet now.

FWIW, the bearing kit alone would not have done it. I slid the old impeller on the new shaft and it still had more play than the new assembly.

I also put a criticool powerplant on the thing....should extend the life of the impeller.

I also took the opportunity to pinesol my system and take a quick measurement of system flow (the 'time to fill a 2 liter bottle' method). I measured just over 2 L/m, which seems high for this rig (see sig). So much for accuracy.

Edit: I did some digging. ~1 Gal/min is about what this system should be seeing.

Probably about time to replace the impellor/shaft on my Mag 3.

Why do they need to be replaced?

General wear n' tear due to mechanical movement over time = less pumping efficiency and more noise...