Air Conditioning - Central AC Leak

I have a leak in our system. Last year, we were very low on Freon, we had connectors checked, sealed and refilled freon. Tech did not fully checked the leak in the whole system. It worked fine last year, now i just started it this year, did not get cool air, it seems freon leaked again. The system is 18 years old. Does it pay to get the leak checked fully (could be in coils) and fixed or should I replace the whole system. It is a 5 ton system. If you recommend to get checked and fix the leak,how do you find a tech who will do this thoroughly and has the right equipment to check it. How much should I expect to pay? Can Sears or PSE&G be considered reliable for this?

Thanks

There is no "logical" reason to put ANY more money into that system.
It is to old and costing you why to much money in electrical usage.
Get a new system and enjoy it.

I agree with AZ. Put the $500 - $800 bucks they'll charge for searching for the leak then whatever it will cost to repair the leak "if they find it" toward a whole new system. 18 years old is pretty much the end of its useful life. Dependeing on the SEER rating you will save money on your energy bill with a new system.

The only thing I would check on a system that old is the access ports (where they connect the gauges) check that they have caps on them. If not put liquid soap on them and see if you have bubbles.


Other then that I would put no money in a sysytem that old.

When a unit leaks the freon like over the winter. The first place to start to look is on the big return line and coil. BUT at 18 years old put the $$$ to a new system
If a gas furnace go for a 90% unit and the AC a seer of 15 or better. Be sure and get 3 bids for the job.

Do you have a recommendation for a preferred centarl Air system (5 Ton) to replace ours, since I have to proceed with the replacement as many of you have suggested. What should I expect to pay?