hi i know its not a mustang but its all the same principle so here goes. we have a 03 f 250 with a 5.4 in it. on the oil cap and in the manual it says to run 5w-20 so thats what we put in it. i just read a chart and it said 5w-20 is mainly for really cold climates. we run motorcraft synthetic. i was thinking we should run 10w-30, what do u guys think, thanks a lot!!!!!

 

i use the valvo 50W in my car i have lots of miles

 

I run MOBIL 1 Full synthetic 15/50.For yours i suggest in the hottest of summer nothing higher than 20/50 and nothing lower than 10/30.

Remember that an engine is a living breathing thing and if its blood (OIL) goes bad like yours you will die and so will it.Just make sure use quality synthetics.

 

the factory spent a lot of time on dynos and road tests to determine the oil recommendation, so why argue with the experts? the 5W oils are also selected for higher mileage reasons too! just remember when it comes to motor oils, opinions are like ********, everyone's got one!

 

ok thanks alot for the info guys!! so u think i should just continue to run 5w-20?? what do u guys think about motorcraft synthetic oils?? thanks agian!!

 

I would stick with what roundmanracing recommends. I run what is recommended by the manufactures manual. The manual should cover extreme conditions,hot/cold, if you find it necessary.

 

IMO....I would switch to amsoil or mobil1 I know ford oil is high dollar and lets face it it isn't made by them..the more important issue is a good oil filter like amsoil,hasting....I would use a good 10w-30 oil...ford also does research on who carries this oil 5w20 and ford is one of the few so they can rape thier cust for $40 oil changes.....5w is good in alaska and the other cold states in winter but using the convental oil it offer lil protection vs a 10w syth. oil......a good magnet oil plug is also a good idea....

AS FOR THE MANAUL READERS DO YOU CHANGE YOU OIL EVERY 5-7500 LIKE IT SAYS...i DOUBT IT