At Thermostat

 1. Fan was on Auto
 2. Cooling was On

Outside Unit was making noise. I turned off power from the outside unit but it still kept making that noise

I went inside turned off the Cooling and noise went away

It has two capacitors
30uf and another small one 5uF

Unit is Lennox

[![3035hvac][1]][1]

1. Is the issue with my capacitors?
2. Can i replace these two capacitors with a single 35uf one ?
3. Or i am thinking it completely wrong and it's something else?



  [1]: https://i.sstatic.net/uxaaH.jpg