I change mine in the ranger every 5k with mobile 1 synthetic. Used to do it at 3k, but it was still coming out clean.

 

I do it every 5000 to 7500 miles now. Mobile 1 full synthetic. My daily driver I do once a year at inspection time. 25k a year with regular oil. Still running great with 143k miles. (95 Pontiac Sunfire)

 

Have you ever seen a motor take a dump because of a oil related problem because of not changing the oil not often enough?

 

No, but I do notice that higher mileage Triton modular V-8 engines, whether 4.6 or 5.4 sometimes do have excessive smoke, I've seen this first hand in Taxis or Police Cars! This tends me to believe that the oil was not changed frequently enough........

 

One reason to hold the oil a little more is to be more eviromental friendly 5000-6000 miles change don't hurt.

 

Think of it like this...engine oil is the lifeblood of your engine.

Yeah, a synthetic will last for 5,000 or 8,000 miles (as far as the thermal breakdown properties are concerned). Have you checked your oil a couple thousand miles after a change (no matter what your driving style is like) and noticed that it is considerably darker than what you put in? That darkening is dirt, soot and unburned hydrocarbons...we'll call all this stuff "mung". All this mung is now circulating through your engine. While I can't say that it is bad for your engine I'll go out on a limb and wager that it certainly isn't good for it. I'm of the opinion that the mung can lead to scoring of the cylinder walls and this subsequently leads to reduced compression and finally lower fuel economy/power.

Just my two cents. Take it for what it's worth. I change mine about every 3,000 miles and use synthetic. It gives me a perfectly good excuse to crawl under the truck and keep an eye on things underneath. Heck, when the weather is nice I could even take a little snooze under there.

 

Yep, GREAT reason to do it yourself.

I had a '97 Dodge Dakota that I put 187,000 miles on with fully synthetic starting with my first oil change. NEVER had an engine problem...lots of other issues though.

 

Actually yeah.. Tore into a junk 300ZX motor I had from my turbo donor car. The oil was supposedly changed every 10k by the previous owner. I drained it as soon as I got it and not only was it dark and nasty, it had sediment in it.

Cylinder walls had lots of scoring. Z31 motors are built stronger than they should be. Even if he beat the **** out of it daily it shouldn't have looked like that. Considering I beat the **** out of my turbo regularly and put Royal Purple in it every 3000 without any issues...

Pretty good evidence to me.

 

Check this link for how far a 5.4 will go on dino oil and infrequent oil changes. AND IT IS STILL GOING http://millionmilevan.com/

 

Motorcraft FL820-S

 

This is what Ford puts on the back of the coupons that they send me

 

Guys who know way more about these engines than anybody on here recommend changing oil at 5000 mile intervals. Sooner if you are towing or doing extensive driving off road. Normal driving conditions mean just that, 70% or more of people fall into that category. If it makes you feel better, change it more often. Or better yet, take a sample of your oil and send it in for analysis. They'll give you much more info. Do a google search, there are plenty of companies that will do it for you.

FWIW, I changed my oil in my 2005 F150, 5.4 every 5000 miles with one exception. I put 2000 miles on it over the course of 3 days all while towing a trailer. I changed it then, and again 3000 miles later to get back on the maintenance schedule. 45,000 miles and no oil related problems.