Dear Car Talk,
I am the first owner of a 1998 Mercedes ML 320 with 252,000 miles. (I’ve driven it figuratively to the moon and am on the return trip. Some troubles along the way, but nothing complicated, until now: the AC is only retaining a Freon charge for a couple of months and I live in Arkansas which can get warmish at times. My mechanic tells me he thinks the problem is a Freon leak around the firewall: 20 hours of labor (@$85 per) to take apart the dash, steering column, etc. plus a $750 part. I think the I asked if there are any Freon-stop-leak additives, and he says his experience is that they don’t work. I am hesitant to invest so much into a likely ‘fix’ knowing that the engine and/or transmission are liable to be the next expensive problem. I hate to emit more ozone-depleting chemicals into the environment if I do nothing except replenish the Freon when needed. Is it time to take some selfies and bid farewell?
Warmest regards, from a long-time listener and follower,