Hello Volvo mavens,

The same evening after picking up my car from the dealer following an alternator replacement, while idling a couple hours later, it suddenly sounded like someone was practicing on a snare drum under my hood.

Nothing shook, but it was LOUD for several seconds.

Was still very near the Volvo dealer, so I drove it back, and left the keys in the drop-off box.

Turns out it was a failed ignition coil.

Someone told me that "When one ignition coil goes, all 6 will soon go".
(I think it was 6)

However, replacing the other 5 would cost $50 * 5 (parts) + $200 (2 hrs labor) = $450

Should I replace the other 5 proactively?

1996 960, w/ 76,000 miles