Impeller replacement question

[GMTK]

Saw a video the other day and the mechanic replaced the impeller (2007 5.7L, don't know model) and said that before starting the engine in the lake to hook up water to the boat via muffs or the water inlet on the engine (for a garden hose) and force water in to the impeller becuase if you run straight to the lake after installation it could burn up the impeller from no water being in the housing. Any truth to this? I plan to replace my impeller then 5 minute drive to the lake and start her up. Figure the lube used for the installation should help until water gets in the housing. I'm running a 2004 4.3L GXI-E.

(I also don't know how water can be "forced" up via muffs but I also don't use muffs.)

 

[Scott Danforth]

Lube impeller with either a drop of dish detergent or a drop or two of water soluble glycerin such as KY jelly

If your in the water, the pump is below the waterline, so it will self prime

 

[silverbul]

ditto

 

[GMTK]

Ok, thanks all.