Wow. I just purchased my first Cadillac. A 1998 DeVille Concours. OMG what a car! I am jealous of myself!

So when I search for oil filters at such websites as acdelco.com or rockauto.com, they all indicate the proper oil filter to use is the PF61. OK, got it.

Each time it also lists the oil filter bypass valve, AC #25013759. Is this something I need to use? I don't get it - I've never had to buy anything other than just the oil filter before. Of course I've never had a vehicle anywhere near this one, so it is news to me?

Do I need this valve? Thanks in advance!

Do I need this valve?

Sure hope not cause I've never bought one.

The oil filter bypass system is for in the event the oil filter gets clogged, at 23 to 27 PSID, the bypass valve will open allowing unfiltered oil to bypass the filter element. This will prevent oil starvation to vital engine components. I have never used one and I'm sure alot of other people haven't either. Will it hurt anything if you don't buy it? I don't think so.

Well, that answers that. Don't need it. Thanks for your help!

The oil filter bypass system is for in the event the oil filter gets clogged, at 23 to 27 PSID, the bypass valve will open allowing unfiltered oil to bypass the filter element. This will prevent oil starvation to vital engine components. I have never used one and I'm sure alot of other people haven't either. Will it hurt anything if you don't buy it? I don't think so.
I suspect that if your filter is so clogged as to require the bypass, you probably have big enough problems to have already ruined your engine anyway.