What is the optimal oil change interval?

[kep5niner]

Every Ford I’ve owned since 2012 has had the Intelligent Oil Life Monitoring system. I’ve adhered to that interval and notification, and it hasn’t failed me yet. Following the IOLM, I’ve logged close to 400,000 miles, running full synthetic in everything. That includes a 2.0L, 4x 3.5L Ecoboosts (to include the current one in the Navi), and my 6.7L.

From the owners manual of the Navigator, which is typical of IOLM across the board:

 

[Mr Big]

The 2025 Ford Expedition's maintenance schedule includes regular oil changes and tire rotations every 10,000 miles, along with other services like air filter replacements and brake inspections at various intervals. To assume you are smarter than the engineers at Ford seems silly but the great oil debate has been going since the dawn of automotive maintenance .

I would never wait 10,000 miles for an oil change on a turbo assisted engine. Years ago, with regular oil, I changed every 3000 miles. Now with synthetic, I use Mobil 1 and change oil and filter every 5000 miles.

 

[Moeman]

With twin turbos and very small oil passages changing oil is important. BUT most over do it. I generally go by mileage and time.
If you have not driven it much the once a year is fine as synth oils do not break down on their own like organic oil. Once you hit 3-4k you should check the color and smell. If its black or smells like gas (not a little bit but a lot) then change it. Otherwise wait till about 5-6k then change it. Older cars from decades ago can go a long time between changes but newer tight tolerance engines with turbos its important to change more often.

I don't really have a strong opinion on the oil change interval comparing older and newer engines, but most of what I've read over the years states that older engines (old as in decades ago, not old as in age) required more frequent old changes. Do a quick search and most hits will agree with this.

 

[Moeman]

I find all of the "I've never had a problem" comments hard to believe. Really? I have examples both ways - back in days past I was a lot more religious about changing oil - we're talking max 5k and typically less than that. Never completely lost an engine, but for sure small things that I could potentially attribute to lubrication issues... and again, that was doing them frequently. For the past 10 yrs or so I've been going more by the life indicator. Haven't had a problem EXCEPT my 16 F150 has an odd noise I've not been able to diagnose for over a year. Keep thinking it's a turbo, but it's infrequent and that darn thing won't fail so I finally can replace it and have closure. So there's an example of perhaps a deserved lubrication issue if, in fact, a turbo does end up failing. But who knows. There are hundreds of inputs into how long an engine will be trouble-free. I tend to think oil change intervals are fairly low on the list. But let the debate continue...

 

[Mr Big]

I find all of the "I've never had a problem" comments hard to believe. Really? I have examples both ways - back in days past I was a lot more religious about changing oil - we're talking max 5k and typically less than that. Never completely lost an engine, but for sure small things that I could potentially attribute to lubrication issues... and again, that was doing them frequently. For the past 10 yrs or so I've been going more by the life indicator. Haven't had a problem EXCEPT my 16 F150 has an odd noise I've not been able to diagnose for over a year. Keep thinking it's a turbo, but it's infrequent and that darn thing won't fail so I finally can replace it and have closure. So there's an example of perhaps a deserved lubrication issue if, in fact, a turbo does end up failing. But who knows. There are hundreds of inputs into how long an engine will be trouble-free. I tend to think oil change intervals are fairly low on the list. But let the debate continue...

The most important maintenance procedures that should be done are oil changes, radiator flushes, lubrication, filters. A lot depends on demographics. I live in a tropical hot sometimes dusty region. So, changing oil, coolant and filters are important. Everyone will have an opinion as to how long before changes. Since I do my own, it is an inexpensive process. Take cooling systems: if you leave coolant in the system too long, without changing, electrolysis corrosion starts and gets worse and can clog and eat the radiator. My maintenance schedule is synthetic oil/motorcraft filter, lubrication every 5000 miles, flush cooling system, check air filter every 6 months. Is it too much? Some will say it is a waste of money, others will say it is not enough.

 

[SyndicateZ]

The most important maintenance procedures that should be done are oil changes, radiator flushes, lubrication, filters. A lot depends on demographics. I live in a tropical hot sometimes dusty region. So, changing oil, coolant and filters are important. Everyone will have an opinion as to how long before changes. Since I do my own, it is an inexpensive process. Take cooling systems: if you leave coolant in the system too long, without changing, electrolysis corrosion starts and gets worse and can clog and eat the radiator. My maintenance schedule is synthetic oil/motorcraft filter, lubrication every 5000 miles, flush cooling system, check air filter every 6 months. Is it too much? Some will say it is a waste of money, others will say it is not enough.

Coolant flush ever 6 months is another level

 

[Mr Big]

Coolant flush ever 6 months is another level

Not actually a full flush. I drain and fill. However, I pay less than $25 for 1 gallon of Motorcraft Yellow Concentrate and about $2 for 1 jug of distilled water. Since it's so easy to drain, I say why not.
Coolant plays an important role also with regard to turbochargers. It helps prevent turbocharger malfunction from overheating. Turbochargers produce a lot of heat, so the coolant, along with the oil, helps manage the heat as it circulates through the turbocharger to control it. It helps cool the turbos and helps stop the oil from thickening and helps lubricating the bearings. When I flush my cooling system, the antifreeze mix definitely smells bad, which is usually a sign of breakdown.

 

[NorthernExMax]

I try to do every 6 months, regardless of mileage, unless i get more than 6k miles in 6 months. Another good indicator is engine hours, like 100-250 hours is what a lot of trucks/tractors use. To me, the heat cycles, operations that I am not at operating temp/never get to it, and then my actualy driving habits all play into it. Sometimes ill do an early one, if i know I am gonna be pretty busy during and after i would schedule it to be maintenanced, so i do it when i have the time. Oil is really cheap, i have over 20 gallons of new oil from previous jobs/good deals that i have been collecting. Almost enough to run my own shop XD

 

[Moeman]

Not actually a full flush. I drain and fill. However, I pay less than $25 for 1 gallon of Motorcraft Yellow Concentrate and about $2 for 1 jug of distilled water. Since it's so easy to drain, I say why not.
Coolant plays an important role also with regard to turbochargers. It helps prevent turbocharger malfunction from overheating. Turbochargers produce a lot of heat, so the coolant, along with the oil, helps manage the heat as it circulates through the turbocharger to control it. It helps cool the turbos and helps stop the oil from thickening and helps lubricating the bearings. When I flush my cooling system, the antifreeze mix definitely smells bad, which is usually a sign of breakdown.

How do you drain it? Not sure what's up with the valve on my radiator but I can't get more than a trickle out of it. Is there a plug in the block that you also pull? I don't think draining just the radiator removes all the coolant, right?

 

[NorthernExMax]

How do you drain it? Not sure what's up with the valve on my radiator but I can't get more than a trickle out of it. Is there a plug in the block that you also pull? I don't think draining just the radiator removes all the coolant, right?

Open the radiator cap to increase flow, or the overflow tank if you have no cap. Draining just the radiator will net about 50% of the coolant, depending how you park. If the front of your vehicle is downhill, you will get some coolant from your engine too.

 

[bb37]

When you are thanking the Ford engineers for their brilliant logic of specifying 10,000 mile oil change intervals, ask them if "reduced maintenance costs" or "low hydrocarbon usage" were more of a factor in their decision than "increased reliability".

Since we all feel confident that "increased fuel economy" is a factor in the decision to run light-weight oil in modern engines, I think it's safe to say that "increased reliability" is not always the primary factor in engineering decisions.

 

[Mr Big]

Open the radiator cap to increase flow, or the overflow tank if you have no cap. Draining just the radiator will net about 50% of the coolant, depending how you park. If the front of your vehicle is downhill, you will get some coolant from your engine too.

I open the tank cap, open the petcock drain plug and let it drain for about 20 minutes. Then I apply low air pressure through the overflow tank, for about 10 to 15 minutes, which starts the flow again. Once it stops, I tighten the petcock and fill. I drive around a bit to get trapped air out and add more coolant. Doing it this way gets close to 10qts of coolant out.

 

[Fastcar]

I grew up in the dark ages when we changed the oil on our family cars like clockwork every 3500 miles.

But in this modern era, with synthetic oils and automated oil quality monitoring, what is the best interval?

Should we wait until the engine oil monitor says 5-10% oil life remaining, or should we stick to a time-based (say, every 6 months?) interval?

We have a 2023 Timberline that is driven very low mileage.

We now have the oil changed at the dealer who uses a synthetic blend oil.

As always, thanks!

I grew up in the really dark ages then I remember when it was every 5,000 miles. Then along came the Speedy Oil change or Quick Change. Anyway that's when it went to 3,000 miles. Penske had to make money!

 

[lobsenza]

Any thoughts on 0w-30 vs 5w-30 full synthetic? The Navigator owner's manual says either is fine. I would like to switch to 0w-30 because my other vehicle requires 0w-30 and I would prefer to use 1 type of oil for all of my vehicles, if possible. Is there any disadvantage of using 0w-30 full synthetic?

 

[SyndicateZ]

Any thoughts on 0w-30 vs 5w-30 full synthetic? The Navigator owner's manual says either is fine. I would like to switch to 0w-30 because my other vehicle requires 0w-30 and I would prefer to use 1 type of oil for all of my vehicles, if possible. Is there any disadvantage of using 0w-30 full synthetic?

I believe the 5w-30 Full synthetic protects the engine internals better. Better lubrications and wear prevention.
The 0w-30 improves fuel emissions but lesser engine internals protection.

So, depends what you would prefer.

Id stick with the 5w-30 full synthetic if u want to prevent engine internal wear

 

[Mr Big]

Any thoughts on 0w-30 vs 5w-30 full synthetic? The Navigator owner's manual says either is fine. I would like to switch to 0w-30 because my other vehicle requires 0w-30 and I would prefer to use 1 type of oil for all of my vehicles, if possible. Is there any disadvantage of using 0w-30 full synthetic?

The 0 part of the 0w-30 is the cold viscosity. It makes for easier starts at really cold temperatures. Once the engine reaches optimum temperature, it becomes 30w oil. 0w-30 is fine in the cooler months. 5w-20 works well too. But they say it's best to use 5w-30 for hotter climates and seasons. The oil is a little thicker and helps lubricate a wee bit better than 5w-20. There has always been an argument between using 5w-20 and 5w-30.
I use 5w-20 more often, because my engine and transmission temps are lower. But I also change my oil more often.

 

[fordperfaddict]

ive gone about 6-10K on my 19 raptor with 105K miles and had 0 issues for what its worth. lots of highway miles and also really hard offroading on that truck. same motor as these essentially.
i used mobil 1 full synthetic. ive had an oil analysis done at about 60 k at the 8K interval. Analysis said things looked food and i could have gone another couple thousand miles.

 

[cgvg1210]

I really should start taking oil samples every 2500 miles or so and send them off to Blackstone Labs. My friend does this with his Mazda direct injected CX5, and says they are telling him his oil is still good at 12000 miles and to go 14000.

Really, I didn't realize there were labs that would test this?

 

[NorthernExMax]

You can order a kit from blackstone for free, you just pay shipping back and a charge for the sampling but that’s only when you send it back.

 

[Flathead40]

Anywhere from 6k -8k for us. Lots of highway miles (easy miles). Over 60k on a 2023 Limited Max already. These newer oils are much better than the old stuff. But it depends on your usage. If you tow and are in the boost a lot I would say 5k tops since since the 3.5s start to get fuel dilution when under constant load.