My antifreeze resivour when cold is about 1" low... and I'm OCD...

so what's the EXACT stuff that's in it? for a 09 tahoe 5.3L

I will be at the dealer to fix a door issue Monday, so hopefully they can add the 2 oz it needs and save me from buying a gallon!

 

If it's the original fluid it will be Dexcool. I use this kind if I get low, $14 a gal, ouch, yeah Id try to get the dealer to top it off.

 

If you only need a couple of ounces don't be afraid of adding a little good old water.
I don't think you will dilute the coolant too much.