I went for about a year and a half w/o A/C in my 91 300E. My Freon was leaking out after about a month, so after some checking we determined there was probably a pin hole in the Evaporator coil. After determining what the cost would be to replace the coil, (app. $2700 done right) I decided heat was fine. I heard about a product called Cryoseal (www.cryochem.com
) which is supposed to fix holes from the inside. After much reluctance by my mechanic and research on my part, I decided to take the risk and try it out. So far (after about a month) I am still cool....but who knows what the future holds. The entire operation cost me about $1000.00. But I paid extra for labor since my mechanic had never done it before and I basicaly had to twist his arm to do it. I can only hope it works for the long haul...time will tell.