Btw, 0R8191 (thats a zero, not O character) is for sure a good part #, it indicates a cat remanufactured part (hence the part # style and the R in the number)
Interestingly, one source here shows 115-4514 as being interchangeable. One of the larger aftermarket parts suppliers. Id call it.... 50/50 that it would work. Lots more 115-4514 around used for sale at low prices . If it were me, id be tempted to grab one of them, since your old cooler is out, would be easy to compare the two, know if new one would work... but thats just me (this is since 115-4514 seems to sell for much cheaper used). If it didnt work, you could always turn around and resell for what you paid.
There are some new aftermarket ones for sale as well. Quality? Well thats a whole different question.... wide range of quality in aftermarket parts for cat stuff. I mostly work on internationals, and the OEM stuff is often near garbage, i mainly only really try to get OEM for some of the sensors / other electronic gear, maybe some seals. For the rest, i often go aftermarket, its usually not WORSE then the garbage international puts out (oftentimes the ORIGINAL DESIGN IS COMPLETE GARBAGE!!! DESIGNED BY IDIOTS, BUILT BY MONKEYS!!). I hate internationals. I can often point to the old part, point to the design flaw that made it fail.... happens almost everyday it seems.
Cat stuff is a whole 'nother league, great designs, great parts quality.
I really like cat.
Which way you go is your call. Let us know how things work out!
As a sidenote, whenever i need parts the first thing i do is just google search (or whatever sesrch engine you prefer) "cat 115-4517 for sale". That gives me a bunch of results fast, from a lot of different suppliers, including ebay and other suppliers, gives me nice mix of used and new parts.
Its very common for me to buy new parts that are NOS sitting on someones shelf / OEM new but opened package, etc. Im careful about that, on ebay i look closely at the sellers feedback rating, and whether it makes sense that they would be selling this item this way (like, if its "OEM new, open package", it doesnt make a lot of sense if they have 100 of them for sale. 1 or 2 makes sense to me.
What im always trying to watch out for is if there are cheap aftermarket parts out there that might be junk, someone could take one of those and slip it into the box / package, claim its "oem open box". Hence why reputation of seller means a lot to me.
As a sidenote, most of the stuff i work on is a small fleet of garbage trucks, or my own projects / projects for friends. Everyone is very cost conscious, so taking risks on used parts/aftermarket suppliers is often very worth it... if i was just running business fixing trucks for third party strangers, it would be harder to justify not going OEM new parts, esp if they were OTR trucks that could be on other side of country if they break down.
Damn i write a book sometimes. I just like to share my mindset on why i do what i do, because it helps explain what i do, how i handle things... because sometimes it makes sense for someone else, sometimes it doesnt. And for guys working on their own trucks, doing their own work (not paying someone else for labor), that use-case fits in pretty well w my situation, so the way i find parts may make sense for them too.
ANYWAYS! When i saw you lamenting over "spending thousands" fixing this (cat parts online shows $2045 for new one, so you werent wrong), i thought id dive in, try to make situation suck less if i could
One last thing, "while youre in there" with truck opened up, lots of drained fluids, theres a few parts in that oil filter module that might be worth replacing, doesnt cost a lot, doesnt take that long. I can provide part #s later if anyone is interested (mainly its related to the valving in there that controls oil flow, pressure for certain conditions, can always have a bit of crud in there / may have springs that can weaken over time...)
