Oil filter bypass valve

What's the harm in running without one installed? I was changing my oil last night and noticed that it wasn't in there. I need the truck so I went ahead and put it back together and filled it up with oil but if need be I'll crawl my gimp ass back under there with a new filter and get the valve installed.
On that note, my truck is a 97 but has a reman motor, I thought the issues with the bypass valve falling out were all on earlier build trucks? Why would a previous owner have removed the thing?
This is what I have:

If you can find the parts in the drain pan you can restake that part in there. The other option is to get the updated one that uses a snap ring to secure the assembly.

Here is the part number F81Z-6881-BA

It would be a great time to freshen up the oil cooler O-rings as well.

That photo isn't my truck, it's one I found online but it looks like my truck.
Problem is I just bought this truck a few months ago, and I already know the motor is a reman from IH. Now I find this which means it's been running with very little to no oil filtration for who knows how long. The parts were not there when I removed the filter. I'm very seriously considering swapping the motor from my wrecked truck that only has a few more miles on it since there are so many unknowns with this one.

i was thinkin it was a check valve to prevent dry starts.

I think it is to avoid overpressuring the filter on a cold start but kinda guessing. I would not freak out and pull the motor over it for sure.

Tom S said:

I think it is to avoid overpressuring the filter on a cold start but kinda guessing. I would not freak out and pull the motor over it for sure.

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close..
it's to prevent blowing the filter apart hydraulically if it clogs, gets damaged, etc..

JLDickmon said:

close..
it's to prevent blowing the filter apart hydraulically if it clogs, gets damaged, etc..

Click to expand...

The info I found elsewhere led me to believe that I've essentially been running unfiltered oil for who knows how long now. If I'm understanding your post correctly that's not the case?

I think you have been running partially filtered oil, but I have not had that piece in my hand to study how it works.

Tom S said:

I think you have been running partially filtered oil, but I have not had that piece in my hand to study how it works.

Click to expand...

correctamundo