Just got a 2014 GLK350 4Matic. It doesn't need a oil change right now but I always used Mobile 1 on my previous Mercedes. Any thoughts with the GLK? Just use standard oil? Also, I dont think there is an issue with draining out all the old reg oil and replacing with a synthetic correct?

 

It should have come with synthetic unless someone swapped it out before you purchased the car.

 

I bought it from a used dealership not a MB dealer. There is a sticker noting next mileage for oil change but not what oil weight was used. Guess I can try to call and find out. If they used regular oil is there an issue with swapping back to synthetic?

 

there will be no issues. if you run non-synthetic the oil will degrade quicker leading to more frequent oil changes which will negate any cost savings. Mercedes vehicles have always been required to use full-synthetic, not a blend or conventional.

 

First thing I do after I buy a used vehicle is change all the fluids and filters and yes, Mobil 1 .

 

 

like everyone else said, change it! My new to me GLK 250 i purchased 4 months ago just had an oil change done, I knew because it had a oil sticker on the windshield. The GLK 250 takes special mobil 1 oil and I knew they didnt use it so I changed it right away.

 

I've seen some DIY videos on the GLK showing users also replacing the smaller o-rings on the filter stem. Is this really necessary for every oil change? Any risk in not changing these?
I ask in large part because the replacement filter (from Purflux and also in the OEM filter pics in this post) only includes the larger housing O-ring. Some users go with the aftermarket Mann filter which includes these smaller o-rings in the package.
Does the dealer always replace these o-rings on the filter housing stem, and if so is this a separate part number (didn't see it listed on a dealer invoice from a previous scheduled service visit).

 

[QUTE=JFATX;7809313]I've seen some DIY videos on the GLK showing users also replacing the smaller o-rings on the filter stem. Is this really necessary for every oil change? Any risk in not changing these?
I ask in large part because the replacement filter (from Purflux and also in the OEM filter pics in this post) only includes the larger housing O-ring. Some users go with the aftermarket Mann filter which includes these smaller o-rings in the package.
Does the dealer always replace these o-rings on the filter housing stem, and if so is this a separate part number (didn't see it listed on a dealer invoice from a previous scheduled service visit).[/QUOTE]

I'd change them to be safe. I've never had a filter not come with them, so that's a new one for me.