I bought my GLE400 at dealer X, which is far away, but the price is cheaper.
Right now, the car is out of warranty.
If I go to dealer Y to do service, is there any thing I need to pay attention?
Many years ago, I over heard that if you did not buy the car from them, they would not give you a free loaner or something.
And, are all dealers' service A , B the same?

 

I have limited experience but I bought from a dealer that was 250 miles away because the closer one (60 miles away) would not deal on the vehicle price or the trade. I went back to the farther dealer three times for warranty issues in the first 18 months but found that their techs were not very good. So I decided to try the closer dealer and am still using them. The closer dealer has not been hesitant to provide a loaner when I've asked and they've volunteered one when they knew that the service was going to take more than a day.

I have built a good relationship with their service advisors and I think that helps. If you can establish that rapport it will help you a lot, especially if you have them do all of your servicing.

Based on my limited experience, I'd say that it won't matter which dealer you go to, as long as their service staff is competent. That's something you'll really only find out through experience and looking at whatever ratings are available from the web. You can also ask them specific questions when you make the appointment. Mercedes the Company, does monitor user experiences so hopefully the experience will be fairly consistent - maybe not as much so as McDonald's, but consistent.

 

Technically you can service the car at whatever dealership you want and the service is the same. They should be giving loaners, but ultimately decisions like that come down to the individual dealership. But what really matters is to build a relationship with your dealership. The more history you have with them, the higher the chance they do goodwill work on an out of warranty repair or go to battle for you. I just had my first out of warranty repair with my C63, and because the warranty had only expired about 2 months ago, they offered me a 50% goodwill. It was a rattle in the headliner, which I brought up fairly early on during my ownership, but back then they didn't locate it. Turned out the headliner was loose and I only tracked it down myself recently, but I had the history with them.

I've had the car serviced at the same dealership where I bought it. I'm a good customer and my SA greets me by name as soon as he sees me pull in. The service manager also knows me, and the entire dealership knows my car. Now part of that is the fact that it is an AMG. You do get noticed and treated well if you pull in with an AMG. I stopped counting how many times they said my car is special in conversations that I had with them and they always take good care of me. I have standing orders not to wash it and not to mess with my tire pressure.

For me it was no different with other brands. I had the same experience with Audi previously, but again I owned an RS model at the time. Even the General Manager there knew me, because he handled my European Delivery when I bought the car, and the service manager at my Audi dealership was from Germany, so as a native German speaker myself, I had a good relationship with him and he went to battle for me several times with Audi corporate. So the point is, don't expect to be treated as royalty by a dealership where you have no relationship and no history. You gonna have to start over and build the relationship.

 

All dealers have the same schedules? For example, Service A, includes A, B, C, D? Service B include X, Y, Z?

 

Such things usually boil down to person you deal with.
Lot of SA don't remember car class, so don't expect them to remember your name.
Personally, I doubt mechanic or SA cares about "loyalty".
Owner of dealership might, but how often he comes to the play?
In the past I heard quite a bit about USA dealers doing "good will" repairs on vehicles way past the warranty, when MB quality was in question. I had such coverage, when my 2001 ML burned wire on pump inside fuel tank and that was vehicle who come from different state.
But did not hear about such good will in USA for years, so looks like policy has changed.

 

Yes, the service schedule and what it entails is dictated by the manufacturer. It also varies by models. The service for AMGs for example include maintenance items that are not performed on regular models. For example the transmission and active differential require regular fluid changes in AMGs, but regular models generally use "lifetime" fluids and getting it changed is either discouraged or is separate from the regular services.