I put synthetic oil in my brand new Mustang and found out I'm not supposed to. Can I switch back?

Hi, Yes, switching between synthetic and conventional oil does not cause problems. Because the oil are compatible , you can switch back and forth as often as you like. thanks john

how would one just find out that synthetic oil is not to be used in that car? did you see that in the owners manual recently,and how was it determined to use full synthetic to start with? it ain't gonna hurt it. if anything,it will help it.you have the 5.0L in your car.Ford switched back from the 4.6L to the 5.0L around 2011.both are very good engines. i have a 2000 f150 with the 4.6L in it...my owners manual says>under Capacities and Specifications to use Motorcraft SAE 5W-XX Super Premium Motor Oil with WSS-MXXXXX-X and API Certification Mark,which would be a blend oil! my truck to my knowledge has NEVER had a blend in it. it has always had FULL SYNTHETIC oil in it.i really think you will be ok.if it were going to hurt an engine,i think i would already know!>>this week,"sometime",i will have 313,000 miles on it!

Let's just say regular oil is fine and synthetic is better. Whoever told you different was wrong. Plus they mix just fine!