I'm replacing the radiator, hoses and t-stat on my 4runner. I looked and found a thread that mentioned a "block drain" on the passenger side. It's supposedly in front of the motor mount and behind the A.C. compressor. Well I did find a 13 or 14mm bolt there. I loosened it, removed it, and nothing came out. I also poked a thin screwdriver into the hole in case there was a film of rust preventing flow. Still nada. I drained about 10-12 its from the lower radiator petcock. Is there more antifreeze to come out of the block? I will also remove the old T-stat and replace that next before dropping in the new rad and hoses. Any ideas? Thanks.