So I got a Cosworth oil pan baffle put into my Toyobaru's FA20 almost 2 years ago now, it has a bunch of those viton flaps on it. All indications are that it's working well so far, but as I was reminded by comments on the 2GRFE oiling article, within the last few months I'd seen that some companies recommend inspecting those flaps every 1-2 years, such as IAG and RSD who sell them:
https://www.iagperformance.com/iag-replacement-viton-oil-pan-baffle-flap-sold-individually/
https://rallysportdesign.com/products/viton-wrc-oil-control-baffle-flap-sold-individually
Oddly they don't say replace, just inspect. I'd simply assumed that those flaps would be good for a decade or two like other viton internal engine seals and could be replaced as preventative maintenance when the engine comes apart for a once-a-decade rebuild. Does anyone have experience with how long these things tend to last and how they fail? If they break off and fall into the oil after 2 years I should probably switch to an all-metal baffle solution pretty soon...
Could you do a non disassembly based inspection? Maybe a camera through the oil drain at your next oil change?
Yeah I was thinking a cheap endoscope through the drain hole could save some work on inspection.
Many years ago in a MKII Golf I had the hinges fail in a swinging oil baffle. The issue was that under higher revs the oil pressure would drop drastically. The flap being loose would get sucked up to the oil pick up and block flow. That was a metal hinge and not rubber like in the link, but I imagine the results of failure would be similar.
Definitely worth inspection, the scope sounds like a pretty good simple solution.
So I think I've come up with a plan that can work with the penny-pinching I'm doing these days, I've already ordered an endoscope and I'll buy a used oil collection pan as well (usually have my shop do oil changes because dealing with the old oil is a PITA). I'll drain the oil and do the inspection myself, if everything looks good I'll just complete the oil change and haul off the old oil. That's about $45 in equipment and it would cost about the same to have the shop do all that, assuming they have an endoscope, but I can do that all on my own schedule which could become important next. So on the other hand, if the flaps look questionable, I'll order a set of replacement flaps, put some cheapo oil in there and drive it to the shop to get the flaps replaced and let them put the proper oil in when done. That would be another $120 in parts and probably $300 in labor if all goes well but not really avoidable - at my experience level I'd rather leave a 2-layer sandwich of FIPG oil pan gaskets to the professionals.
So I don't think I was able to see all the flaps but the ones I saw are all hanging down at the normal ~30deg angle so I guess they're good. No signs of anything out of place.
Really not looking forward to doing that again though. About 1qt of oil skipped right out of the drain pan and onto the driveway 
I had almost enough cat litter for it...
