Differernce between OEM and Genuine parts

An OEM [Original Equipment Manufacturer] part will have the original manufacturer's branding on it rather than a Mercedes logo.

Example is things like injection-system parts: they're all made by Bosch but ones made for Mercedes will have a Mercedes

If you can crack the Mercedes/Audi parts-codes you can get the same parts from a Bosch dealer with a Bosch logo on them, generally at a much lower price. Same goes for things like relays/switches [Hella] and oil/fuel filters [Mahle].

Aside from the logo - is the part identical? i.e would a Textar OEM brake pad be the same as a "genuine" mercedes brake pad?

Or are they made by Textar / Ate etc but of different qualities??

So what is the difference between a "genuine" part and a "Genuine parts in their packaging" - now I assume that the ONLY differerence is the packaging?

not sure for cars but i know for PCs if you order say a OEM Hard drive you get a hard drive in a brown box, whereas if you buy the normal retail version you get the proper box, instructions and everything (more expensive tho..)

Yup. Computers seem to be "OEM" and "retail" the former being designed for those who are building machines to sell on. I guess the same is true of cars, dealers etc will buy OEM parts because they have no use for fancy boxes.

There is the possibility that quality control is different on supposedly the same part, though.

I'd hope you'd certainly get genuine parts out of maker's boxes at a dealer - you'll be paying that price, after all.

That depends. You need to consult the catalogs in detail. All the OEMs will sell parts in their own boxes/under their own brand, and may issue a catalog that lists the equivalences - however you sometimes get an OEM "Budget" part being offered as well as an OEM "Premium" part; both do the job but it may be that the 'budget' part is of lower quality/different specification.

Could be a "grey" import. I've seen this in the past, some as-far-as-I-could-tell genuine Volvo brake-disks not-in-Volvo-boxes but with Volvo labels on them. I guess if you're shipping parts for fitment by your dealers there's no need to put them in the snazzy boxes!

No.

THe best example is body panels where OEM ones are rarely a good fit.

Conor ( snipped-for-privacy@gmail.com) gurgled happily, sounding much like they were saying :

Truly OEM ones would fit as well as dealer-supplied, because they're made on the same press.

It's pattern ones that rarely fit. Pattern != OEM.

D'Oh!

This reminds me, I bought some oil for my BMW not long ago. The oil can only be bought through the dealer for about £13/litre. It comes with a little zip-lock bag containing some BMW dipstick wipes and a little plastic funnel. Personally I'd rather just be able to buy a gallon of the stuff at a decent price.

Somethings I'd be happy with alternative but others I wouldn't. When it comes to important items you generally get what you pay for.

It's actually Castrol, but I can't remember the grade. It's no more expensive than other premium oils in the US - not that this helps us. Perhaps someone knows a UK supplier?