I have a 2000 F-150 4x4, 5.4L. 67000 Miles
After reading alot on this web site & other sites I decided to switch my oil from standard oil to Mobil 1 synthetic. I just changed the oil yesterday to the Mobil 1. While I was under the truck as I am sure most of you do , I was checking other stuff & looking for leaks. I noticed that at the back of the oil pan there was some oil. It was not coming out right then but it had been seeping out for a little while because it has hardened & had dirt in it, I am sure you know what I mean when oil has been sitting on a part under the truck for a long period of time. I have never seen any puddles under my truck so I dont think it is anything but a leaky gasket. I could be wrong though.
The truck is still under waranty so I was going to take it in & have them fix it.
I have 2 questions!

1. Will the synthetic oil make this worse? I have read that the sythetic can
open up small leaks.

2. If I take the truck in for service & they fix the problem & just put in regular
Motorcraft oil, will this cause a problem? I have heard that once you
switchto synthetic you cant go back. Should I just tell them I haveMobil1
in there? I wasnt going to because they could say that the leak opened up
because of the synthetic oil & I dont want to give them another reason to
charge me more money. Plus they probably wont believe that I just
switched to it this past weekend & that the leak was allready there.

Thank you in advance.

 

I'm not sure if the Synthetic oil will open up the leak or not, but I can say from my experiences you may switch from Synthetic to regular oil. . When I got my truck I did about 5 oil changes with synthetic... One day I took it down to the 10 min oil exchange and they put regular oil back in it... "oh well"... I have 110,000.00 miles on it now, and it still runs like a top...

I wouldn't mention anything to the dealership if I were you. . Just tell them you saw an oil spot, and leave it at that. . Don't offer anymore information.

Ken

 

Unless you are losing alot of oil, I would not worry about it. This sounds like a pretty minor leak, and its not leaking enough to leave a puddle so I wouldnt think about it too much.

Yes it is possible for synthetic to open up small leaks, but with only 67k I would not be TOO worried about this.

 

No problems. My dads aviator has 14K miles, just had under warranty the rear main seal replaced, oil pan gasket, and the tranny disassembled and all kinds of new stuff in there. THey of course drained the fresh synthetic and add 5/20 Ford branded regular.