Just picked up a 2005 zr2 Blazer and went to do a radiator flush but can't locate a drain plug, what am I missing. I found what looks like it should be the drain but it has no plug. Is this not the drain, any thoughts? Thanks

 

I want to say someone put a screw in that hole lol(NOT so lol.....)

 

I took me a moment to get my bearings from your picture. As Don said, it looks like some plugged the drain for the spigot by shoving something into it.

(picture grabbed from RockAuto)

 

How's the quality of the coolant? If it seems really bad, it may be a good idea to just replace the radiator.
When I bought my 4WD 2Door Blazer with 110,000 miles on it at the time, A/C system had no heat. Soon after driving it, the water pump went bad and I replaced it.
After replacing the water pump, I decided to flush the heater core, and that's when I discovered an orange snot that was clogging it up. It still had the factory original DexCool that caused these sorts of problems. That's when I decided to replace everything in the cooling system.

 

I have an 05 non zr2 and I’m looking to do a coolant flush soon so I checked out my drain plug and I have the exact same thing. Very strange. I guess I will just pull the lower hose.

 

Must be what people do when the drain plug gets broken.....

 

Wondering how many more 05s are like this..

 

Yes it’s very weird, I wonder if all 05s could be like this maybe.

 

My radiator was full of black crap that settled to the bottom and presumable into the lower hose so even if I could open the drain it wouldn't drain much. I couldn't get to the hose. so I took it to a radiator shop and for $400 they drained everything, replaced the rad and now I enjoy opening the cap and seeing a clean light green coolant.