We've had threads discussing how many miles to go on an oil change.
Opinions ranged from using the Ford on board system, which can let you go
10,000 miles, to "Ma pappy done said ya gotta git that ol' all outta thar every 3000 miles." Needless to say, we didn't reach a consensus.

So here's a different question:
3 owners, Art, Bob, and Charlie each believe in 5000 miles between changes.

Art drives 10,000 miles a year and changes it twice a year. No problem. Right?

Bob drives 5000 miles a year and changes it once a year.

Charlie is gone from home most of the time and only drives his vehicle to the airport, then back a couple weeks later. He does this once a month and it's 100 miles each way. Otherwise the vehicle sits.

So he drives 5000 miles in 2 years. Any problems there?

 

I have no science to back this up, but I would change the oil in ANY vehicle at least once per year.
On modern vehicles with Oil Life Monitors, I will go by those as well. It seems to me that in both my truck and my wife's minivan, we're changing about every 8-10 months, which is around every 10,000 kms. If the OLM said it was good, I'd have no issues going out to a year, regardless of distance travelled.

Those my my two cents, which these days won't even buy you a stick of gum . . .

 

It's also a matter of the type of service as well. If the truck sees only short trips, then the engine sees lots of oil contamination, mostly sludge, unburned fuel and acid formation. If the truck is going to be parked for extended period take it out for a good highway run to burn off condensation. Changing the oil too often won't hurt anything but it is a waste of money and presents disposal issues.

 

The best way to know when to change your oil is to have a sample analyzed. That is what I did to find that I can run the Royal Purple synthetic more than 10K miles. I tested it at 5K, 8K, and then at 10K when the analysis came back showing it could go farther.

Oil sitting in an unused engine does not degrade very much. Heat and other factors cause the oil to oxidize and fail. Fuel contamination isn't very likely on healthy engines, but there are cases of folks with the direct injection engines showing higher level of raw fuel in the oil.

If you have to sit around worrying about your oil every day then it might make you happier to just go ahead and change it to keep your mind at ease.

 

Honestly, I don't think there will ever be one definitive answer that all will agree 100% on this subject, I can't find fault in any of the above answers, but still prefer my own methods. I agree with seventyseven250 that no matter the mileage, I'd change the oil in a year, I also think that an oil analysis isn't a bad idea, but unless you are in the exact same conditions every oil change, with is pretty much impossible, I can't see that I would personally rely on that either, certainly a good information provider though.
I personally don't go over 5,000 miles (normally)I have been told that I am probably wasting money, but I have peace of mind.

 

Here's a related and somewhat loaded question:
- How does the on-board Oil Life Monitor decide how much life is left in your oil? What parameters is it tracking and how does it measure these?

 

i go 7,000 which for me is about 8 months.

 

Most companies use a computer algorithm to determine when the oil change is needed. They track data such as the number of times a car is started, how long it runs, the temperatures and other information from the PCM. I am conservative and change my oil when there is 20% life left, (about 7,000 miles). I don’t want to give big oil any more of my money than I have too but I’m having a hard time going past the 20% mark. Here is a link to an FAQ page on Ford’s web site.
Frequently Asked Questions

 

At least for my '09 and '10 GT it seems to be more time related than anything. When my F150 sits most of the summer the oil life gets to 5% in 3K miles, during the winter when it is driven more it hits 7K easily. Same for the Mustang, not driven much and it can hit 5% in 2K miles. Just had to reset my F150 the other day as it got to 4% in only 3300 miles.

As for the examples I wouldn't have a problem going 2 years and 5K miles, we have lots of machinery that doesn't get an oil change every year, some go as long as 3 if not used a lot. Oil tests always come back good in terms of how the oil held up.

 

the Oil Life Meter (OLM) in your f150 is not what ford calls its "intelligent" oil life meter (IOLM). the IOLM uses algorithms as described above to calculate when the oil needs to be changed.

the OLM in your '09 f150 is a glorified timer. it will tell you to change your oil every 6 months, or 7500 miles whichever comes first.

that is to say, if you change your oil and reset the meter, then let the vehicle sit unstarted for 6 months, your OLM will say to change the oil. Likewise, if you were to put on 7500 miles in a month, it would tell you to change it at 7500 miles.

i suspect the OLM in your mustang is likely the same, although i didn't specifically look it up.

the f150's got the intelligent version (IOLM) in 2011. IIRC, the IOLM will still tell you to change it once a year, regardless of miles or calculated oil life remaining.

 

I have nothing to back this up, this is what I do.
New vehicle change it after 500 miles.
Change it twice a year (spring/fall) or every 3k to 5k miles.
My truck will have about 3k miles at the year mark. Oil has been changed twice and will be done in about a month? or so?

 

Think of it like this: In the case of my truck, it sat on the dealer's lot from 01/11 - 06/30/11. It had 20-30 miles on it from test drives, etc. I brought it back for it's first complementary change at 2600 miles and the service writer thought I was nuts. I explain ed that the truck sat for 7 months plus it's build time before it was bought, he was unmoved but serviced it as I requested.

I've since settled into a 5000-6000 mile dump cycle. My wife drives her Expedition about 5500 miles per year, it gets dumped annually or at 5000 miles and no issues after 102K.

 

Never hurts to change it. It can hurt not changing it. So magic number, whatever feels good to you.
My new one is getting it at 1500 then 5k 10k 15k. Just what feels good to me. But also going to Mobil1 one cause that feels really good to drive.

 

Every 5K on Mobil1 seems like a waste of money to me but its your truck, your bucks
Edit: I see you're in PA, whereabouts? Maybe I'll come get your used Mobil 1 and run it another 5K in my truck lol

 

It's pretty much a persons preference . I've used AMSOIL for last 18yrs with no problems, changed @ 10k-15k miles., just depends on my mood.

I don't see the purpose of running synblend, just run full synthetic ! My new 15 came with synblend motorcraft first change will go full synthetic ....