A capacitor can be bad without showing any signs of leaking or venting out the top. What you need is to test the esr with an esr tester and If any of capacitor read high esr that means there out of spec. I don't know about all esr tester but mine can measure caps in circuit as long as there are not in parallel with a nother cap.
Here is one I have it is kinda pricey but very well made. Mine was a little cheaper as I bought the kit version not the already built one
https://anatekinstruments.com/produc...esr-meter-besr.