I've got a 2001 3/4 ton cummins that I bought new...170k on it now....For years I took to get oil changes at those quick lube places...I bought a new Chrysler 300 about three years ago...For about a year I took it to Quick lube places to get the oil changed.....One morning the after I had taken it to get it's oil changed, I happened to check the oil after it had been sitting all night..The oil was grossly overfilled....So I checked my truck and It was really overfilled as well.....
About the same time an elderly neighbor had to get all of the seals replaced on her car..She had less then 100k on it although she had taken it to one of those quick lube places for the entire 12 years she had owned it....I figure that the quick lube places change the oil so quickly that oil in the engine hasn't had time to drip down into the pan and they fill it to the full line on the dip stick and show it to you filled when it's really overfilled.....
I'm getting ready for a long trip, so I took my truck in to a diesel shop that I've used for years and believe is honest, for a pre trip check up...They told me that several seals are leaking... Their going to replace all those seals, and also replace the water pump and differential fluid....2400$...
I figure that the quick lube companies know that their overfilling engines with oil leading to seal failure, but that failures occurs several years and lots of miles after the car is new....By then the vehicle is probably owned by a second or third owner and no one's the wiser as to the real cause of the seal failures.....
As for my Chrysler, I only took it two or three times to those quick lube places so hopefully the seals are OK....I now change my oil......
OH BTW, I told a coworker, who had used a quick lube type place to change his oil, about this...He checked his rig and it was overfilled..He now changes his own oil......

 

They would have to be more than just "slightly' overfilled. I know people can be idiots, but you would think they couldn't afford to put that much extra oil in every cummins to get it high enough to cause problems.. I think mine holds 3 gallons just to make it to the mark. One extra gallon isn't cheap,..and I'm not sure how much higher one extra gallon would make it.

On a car,..ya, that's another story.

 

I don't think over filling causes the seals to fail but can certainly cause them to leak until proper level is restored.

BTW, I did some FCA training last year and they recommended Cummins engines drain for 30 minutes. There is not a lube place in the world that will allow that amount of time to change your oil.

 

They're not putting in an extra gallon..They put in the correct amount to fill it without allowing the oil that's up in the engine to drain out properly....I now drain both my vehicles overnight....

 

You get what you pay for......I do mine myself so I know it's right.

 

^^^That^^^and they use cheap filters. Last time I bought a couple of Fleetguard Stratapores from Cummins, the counter guy tells me they keep seeing engines damaged due to cheap filters coming apart. Said I was smart buying Cummins filters. Imagine that...

 

I order the same filters from Geno's by the case, so I always have them on the shelf.
Oil changes on the Cummins trucks are so easy and clean.
I can pull an old filter and install a fresh one with hardly a drop on the shop floor.
Try that with the oil filters that mount at a steep angle on the side of the motor...