[BR3W CITY]

The 255 is pretty much the most common part. If its whining, there are a couple things that can be at play;

Heat/lack of cooling is a function of flow. The pump needs to have cool gas passing through it, so mounting locations are important. Where is your pump? The higher and further away it is from the pickup, the more suction force the pump needs and strain it puts on it while running dry.

If you have a restriction from a clogged filter, too tight of a micron rating, or just too many filters it can cause similar issues as well (so would a pinched line for that matter).

Also, doublecheck that you have a good hot wire and solid ground. The pumps draw decent amps, but you can put a multimeter on one and see what your drawing. If the internal motor is drawing much higher than whatever they are rated, it means the motor itself is dying. A bad ground or low voltage can kill one just as fast.