OE vs OEM parts are they even same?

[mikkhh]

Most truck or engine manufacturers make their products from outsourced parts.

There are companies who make engine parts - pistons, bearings, gaskets. There are companies who make filters, who make suspension parts, who make bearings.

There is two kinds of parts genuine original equipment parts that are sold by original equipment maker. And there are aftermarket parts that are suppousedly made by original equipment manufacturer - the same company who makes parts for original brand, in theory same part minus the original equipment manufacturer logo and therefore steep discount in price.

I have tried myself car suspension parts (bushings, engine mounts) that have same manufacturer as the original equipment. But most of these parts do not last nowhere as good as the old part or part from dealer.

Brake pads are interesting story, original ones from truck or car are made by few companies. When you look up the company who made the part from old brake pad or brake caliper and buy part that is made by suppoused OEM manufacturer the brake pad is absolutely different braking wise, there is increased dust and sometimes even noise. So those parts are not the same.

What about filters ? Most filters when bought from OE manufacturer have OE logo + part number for OEM manufacturer part. Is there actual difference in for example the amount or type of filter material? Are OEM manufacturer parts ones that did not meet OE equipment quality control and therefore are rejected parts that are sold under OEM manufacturer name brand?

Engine parts wise European cars have pistons usually from mahle (japanese have art pistons), bearings from glyco or kolbenschmidt. BUT when you order main bearings from OEM manufacturer those are sold as a set, but OE part is sold by piece and there are 3 different sizes of standard size bearings available (OE part costs 10 times more). The bearings are not the same - for example thrust bearing is clearly different. So it means that those OEM parts may not be even quality rejects in this case but completely different parts instead.

What about truck batteries? When you use auxiliary heater lots of time then aftermarket big name brand batteries last 1-2 years. Genuine truck manufacturer batteries bought from dealership last many times longer.

Another question rises about new original parts bought from dealer vs the parts that are on truck or machine from factory. These parts should be the same quality or the original part on machine might be better? No?

[Rawze]

non-oem branded parts are often lower quality, even if from the same company.

[mikkhh]

I understood that OE part is Original Equipment manufacturer let's say in the red engine case cmmins itself. And OEM is Original Equipment manufacturer for in this case let's say filter or bearings manufacturing company.

But what about the parts that new engines are assembled from VS the replacement Original Equipment part that you buy at dealer? Is there some quality difference to be expected?

What is the story with old part core charge being same on NEW or reman part? The local dealers are just trying to screw over customers?