I have become distrustful of my radiator cap, a Motorad 16#, tightens with the two ears. I lose water and the overflow level never seems to change, Also, I think there is a button on top that is supposed to pop up but I have not observed that. I'm supposed to use 15#, but those are pretty rare for cars and don't get good reviews.
Suggestions?

 

You just might need a new one. Is the current one old?

 

Yes, I'm looking for a recommendation
To buy one, sorry.

 

Your radiator uses a 16 pound cap, not a 15 pound. I recommend a Stant safety release cap, part # 10330.

 

A couple questions OP:
What climate area are you in and do you do any towing?

 

Hot. Houston, 100 deg summers, did not drop below freezing this winter. I run distilled water with just a pint of antifreeze, overflow tank, no towing. Runs 190 degrees usually.

 

I'm not even going to explain why your coolant mixture idea is so wrong.

 

Mine had this on it when I bought it but I don't like this cap.. 1. Not sure they work as intended and 2. Hard to get on and off. Good cap for cars with head gasket issues though..

The OE cap is NOT a 15lbs cap ? Thought it was..

 

What do you use Tahoe?

 

ACDelco OE model cap. Model number RC95. 15lbs.