The Z-best worked good for me for about 4 or 5 engines then it jelled with about 1/4 of the can left and did not work well at all. This stuff is kind of pricey if I remember it was about $8 for a can that held about 1 pint. I need to come up with a crock pot and try the anti-freeze method, I have heard repeatedly it works wonders. Remember if they don't look good they won't fly! Hmmmm maybe that's my problem.