First time audio installer and first time with components. Sony XS-162ES running passive though supplied crossover. Seperate channel for each speaker (pair using 4 amp channels). Someone told me to solder in a capacitor after the tweeter crossover on positive side as a "safety net." What size capacitor? I've been told 1.5uF, 47uF and 50uF. Also was told 250v??That's quite a range. Not looking to use it as cilrissover but mainly to protect the tweeter from start up pops and such. Im not a math guy. Thanks.
Do you have a pop when you power the amp or shut it down?

The xo has separate inputs so you should use the crossover, even if using active crossovers.

1.5 would alter the crossover point. The others would not.

The voltage rating of the cap would be determined by the power driven to the amp but it's unlikely that the tweeters would ever see more than 50v. Higher voltage is OK, as well.
Had a pop on startup but system was previously wired into factory harnesses. I gutted the Tahoe for sound deadening and sound proofing so ran new larger strand wire from amp to speakers. Found some rca lines running along power wire so got all those seperated. Moved the amp ground from seat bolt to frame and chassis. Ive also added extra grounds in engine bay.

I understand now there is no need so thanks for that. But if I go active I know I need one so I guess my question now is will (2) capacitors hooked in line with same values act as as if there is only one? Just in case one fails or is removed?
The second capacitor (of the same value) will raise the crossover point because the two capacitors in series will effectively 1/2 of the rated value of one.

There is more of a chance of you winning the lottery than having the capacitor in the crossover fail.

Using the crossover with individual inputs will be the same as installing a capacitor in its place.