I just hit the 3,000 mile mark since I bought my 04 Mustang and wanted to know what's a good oil to use. The oil cap says 5W30 but with the heat here in Texas I'd think it would be better to use something thicker. My mechanic buddy said 10W40 but wouldn't 20W50 be best in the 105 degree heat we have here on a daily basis? Also, should I use regular dino or synthetic?

 

Most guys use a 10-30, and synthetic is the only way anymore

 

I vote for synthetic also!

 

Owner's manual says 5w-20 Synthetic....6qts

 

I use 5w-20 in the same heat as you, and my car is fine.

 

Motorcraft blend
Great price/quality

 

10w40 and 20w50 are way too thick for your engine. Modern engines are built with tight tolerances.