where's the radiator drain plug...

[akshay]

...on a 1997 5.7L GMC K1500 z71?

[GMCTech]

Should be on the lower right (passenger) side of the radiator. It is sometimes tough to get to, just about over that right framerail. I normally just take off the lower radiator hose.

 

Hope this helps.

[citydriver]

On my '95 its on the left side(drivers) right under the engine oil cooler line and its plastic ....its also a pain to open cause the oil line is in the way....be carefull not to break it if yours is the same