I have 2 floors and 2 separate AC units. First floor has a Goodman compressor manufactured in 2012 3.5 tons and the coil and furnace is Lennox brand made in 1996. I called an AC guy because it started blowing hot air not cool air like it supposed to. He checks the compressor and tells me it is leaking and he placed 3lbs of Freon. He told me it is not possible to change the coil, it is too old and the new ones can not be installed there etc etc. So he told me to pay like $100 every year for Freon and be done with it yesterday, AC stopped working. Called another AC guy he checks out and finds that thermostat wire were touching each other or something like that and I went to walmart and bought a new thermostat he installed it, now it is working I showed the coil to this new AC guy and he said he can replace it with Trane coil for $1,500. Then he said I better be changing furnace and coil together but dis not tell me the price on both yet. Appearantly he does not have a problem with size or dimensions and says trane coil will fit in there. What do you guys think?

So last year the A/C tech who serviced my unit wrote this down "low run cap but within specs". I came home today and the compressor was buzzing, and would take 3-4 tries before it stays on and begins cooling. Does this sound like maybe the capacitor is the culprit? The fan is running the entire though, so that's why I want to ask since I am not very familiar with House HVAC I am fluent in automotive A/C, so I'd like to DIY it if possible. If the problem sounds like the cap, can someone tell me how I can find the right part that is compatible?