why does ford recommend two types of oil?

[haymaker]

why does ford recomend 5-20 oils in most all of their engines and 5-30 in other engines if they think that 5-20 oil is better. i have a 2005 ford explorer with the 4.0 V-6 engine and it says to use 5w30 on top of the oil cap. it says the same thing in the owner manual too. my son has a 2004 ranger with the same engine and it says to use 5w30 also.
what makes the 4.0 different from the other engines?

 

[Big Jim]

It's not an American design. It is a German designed engine. Evidently the American and European engineers don't talk to each other.

 

[tenderloin]

Not sure the exact reason.... It could be that the 4.0 sohc is an older design and for a time Ford had a problem with the 'cam chain tensioner'

I have a couple in '05 Explorers and am very happy with them. I am currently using Torco 5w30. Smooth, quiet and get over 22 mpg on the highway, 17 around town

 

[TallPaul]

I'd run 10w30 in the 4.0 if it were mine, perhaps with some 10w40 in the mix to thicken it some.

 

[manicrodder]

They spec 5w50 in the Ford GT and the new Shelby 500.

 

[427Z06]

This engine is a derivative of the German Cologne V6 designed more than 3 decades ago. Old German design = thicker oil, quite often.

 

[Old Mustang Guy]

This is the type of question that many of us wish we had a definitive answer to. I am a Ford guy and a user of 5W20. My 03 Cobra speced 5W20. As far as I know the new Shelby motor is essentially a 5.4 version of the same motor. There must be a reason why they chose 5W50. Ford issued some info back in 01 that indicated that their existing motors that did not spec 5W20 would be modified to use it, yet the 4.0 still uses 5W30. I have wondered if this motor will be phased out with the new 3.5.

 

[haymaker]

this is why i think they they wanted the 5w-20 oil for gas mileage only to meet their mileage standards. it doesn,t have any thing to do about their close tolences in their engines. i have a 1996 lincoln town car also and it says to use 5w30 oil, and ford comes out in 2001 and said they recomend 5w-20 oil now in previous modles back to the late 90s modles. i am really confused now. maybe the 4.0 motors are way better than the other ones. just my 2 cents.

 

[427Z06]

Although they are the same basic architecture, there are many differences between the Cobra and the Ford GT and Shelby 500 engines. Further, the Ford GT and Shelby 500 engines are very low production items, full of aftermarket pieces that don't go through the normal Val/Ver process. Power levels are another determining factor.