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Bad Oil Change - Need Advice

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I had my Boss in for service at my dealer for a whine at 65-80MPH. They replaced the rear axle gear and pinion assembly which has helped a little. They also said I had a free oil change in their system and I was ready for one anyways. The service advisor told me it was good for whatever the car calls for and in this case 5w-50 full synthetic. They've done it before so I think no problem.

Go to pick the car up and the paperwork wasn't ready. They said they'd just mail it so I'm fine with that and leave. Get the paperwork a week later and find out they put 8 quarts of 5-W20 in it. I've put about 500 miles on since then. Has this possibly damaged my engine? How do I go about making sure? What should I expect out of the dealer other than draining the oil and putting the correct oil in?
Unless you've been tracking the car with the 5/20 in it I would think you would be fine, just normal driving. My wifes Navigator has never had anything but 5/20 Motorcraft and approaching 150K miles with no problems and doesn't burn a drop.

It could also be that the tech did it right and the service writer just entered the wrong info on the invoice. It seems that anymore they will find the dumbest female around that knows absolutely nothing about an internal combustion engine or anything mechanical and put her behind the counter writing down whats wrong with the vehicle.
I'm also concerned about the work they did with the gears. If they can't get the oil change right when it says 5w50 right on the cap what else did they screw up?
my dealer did the exact same thing and I noticed it before I left. Then, they argued with me about what oil was required until I showed them and made them put the correct grade it. Now, I do my own oil changes regardless of the free one I have left with them!
my dealer did the same well at least the paper work said 5w20 when i questioned it they claimed of course we put 5w50 in. it was during the winter i didn't really care.
So let's say the paperwork says they used the right oil. How do you know they did?

I also change my own oil and filter.

I doubt any damage was done but I would maintain documentation of the 'mistake' just in case.
The old paperwork (which I still have) says 8 quarts of 5w20. The new paperwork shows 9 quarts of 5w50 and that's what it showed in the past. Now I didn't watch them fill it up (probably should have) but at least I have the documentation showing the mess up.


Life is short. Live well!
Quick Lane does my oil because of the price (half off) but I never let the car out of my sight. I visually check every bottle of oil that goes in it. They are cool as long as I don't go under the car while on the lift.
I wish I had the time and space to do my own work. However, under the warranty period I like to work through the dealer to avoid any issues. I guess that didn't workout. LOL
I would never let them touch my car again,brain dead.I never let the dealers touch my cars because they hire BOCES students who are just learning the trade.Back in the 80's I had a recall on front springs on a car I had bought from a Ford dealer,every bolt on the front struts were loose,I have never let any dealership tough any of my cars since with the exception of the Track Key installation.
Jeff said:
my dealer did the same well at least the paper work said 5w20 when i questioned it they claimed of course we put 5w50 in. it was during the winter i didn't really care.

If I remember correctly the GT calls for 5w20 so my dealer was insistent that my car was the same. If I also recall correctly it says right on the filler cap 5w50!!!!

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