We kindly need any suggestions regarding the purchase of the best model of an AC leak detector ("sniffer") to find a difficult leak in the AC system of a 1991 740 Wagon, previously converted to a 134 system with the Volvo kit. Have tried without sucess a Robinair model. Have heard very good things about a sniffer manufactured by Yokogawa. Also, a local repair shop recommended a Pep Boys Product identified by the trade name "TIF."

Having to keep the AC working on several older cars, I can justify spending the money for a detector but I want to get the best one for the money. Any recommendations, with specific models, would be very dearly appreciated. A sniffer seems to be really necessary to try to confirm a leak in the dreaded evaporator - last replaced about 6 years ago. Again, my great appreciation, as always, Larry.