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Oil: Synthetic vs Natural

I’m sure this is a hot topic, but here it goes:

I’ve got a 2010 Ford Focus SE that I bought used last June. It had about 57k miles on it at the time, and now has about 72k. When I got it, my daiy commute was about 10 miles round trip, then I moved and my commute increased to about 25 miles.

I am now, with a job change, commuting about 100 miles round trip, mostly between 50 and 75 MPH.

The question is, should I switch from the “natural” engine oil to synthetic? Everything I’ve read so fat indicates that while it costs on average twice as much, synth can let you go three times as long between oil changes. And at about a thousand miles every two weeks, if I can go 12k miles instead of 3k between changes, that would be quite nice.

No need for 3k changes with a 100 mile commute. I would use the oil specified in your manual, and change it using the ‘normal’ interval. What is that interval? It should at least be 5k, if not a bit longer.

I absolutely agree with Texases.
I strongly recommend against going the durations that the purveyors of synthetic oil suggest. Synthetic oil suspends microscopic particulates, is subject to dilution due to blowby, removes heat from the cylinders, and does all of the things that dino oil does. Your goal should be to get the engine to last as long as possible, NOT to get the oil to last as long as possible. These hyper-long periods between changes are marketing hype.

Synthetic oil and dino oil are chemically the same stuff. Synthetic has fewer impuities, and the molecules are allegedly more consistant in size, so they stand up to heat better. But both are oil.

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One more thing - going to the recommended interval will require the OP to check the oil level periodically, something that might not have been done with 3k change intervals.

Excellent suggestion. And since you’re driving so many miles, I’d suggest checking it every other day until you get a feel for how much the engine is using. A minute every other day can help your engine last for many years.

@ Gordol…just as a note of reference, honda accord users have had regular 5w30 motor oil/not synthetic in their engines for a long time and their oil change intervals have been 7500 per the manual (specifically 2000 v6 version), so don’t be afraid to follow your manual as it knows what it is talking about/and you have a lot of easy freeway miles in your commute.

Everything I've read so fat indicates that while it costs on average twice as much, synth can let you go three times as long between oil changes.

Absolutely NOT. No manufacturer that I know has different oil change intervals for Synthetic oil or Dyno oil. The oil change interval will be EXACTLY the same no matter what oil you use.

As for needing synthetic. There are many people in this forum (including myself) who’ve owned vehicles with well over 300k miles using nothing but regular dyno oil.

The only reasons I see to use Synthetic.

. Towing.
. Turbo.
. Live in a real cold area where temps can get to -20 or lower on a consistent basis.
. The manufacturer calls for synthetic.

@Gordol … don’t fall for the hype about synthetic oil. I agree with the others here who would have you keep your regular oil and change it on a 5K interval. Don’t waste your money on synthetic oil. If your owner’s manual calls for synthetic then use it. Until then…leave it on the shelf.

My friend has this car with a long commute. She has 100k+ and follows ford recommendation of every 7500 miles. My guess she uses the Ford spec oil(likely normal) not synthetic.

12k vs 3k on oil changes ? Wow, with all due respect to the frequent oil change fanatics, 3K is way out of line IMHO unless you have a real special need. 5k is perfectly fine on non synthetics and 7500 to 10k on synthetics will make your motor last as long as any 2500 oil change interval on older cars. Have you noticed how long motors are lasting ? Regular oil changes and not skipping them is important. Personally, I am using synthetic to 7500 miles on one vehicle and 5k non on the other. After I get over my fetish and feel comfy, I will move to 10k synthetic on the car that “requests” it, never look back and have a motor that will easily out last the body…

I completely disagree about supposed hype of a good synthetic. It’s like “read the owner’s manual on some things and they become wrong when we know better on others ?” Selective reasoning and it’s incorrect IMO.

In cold climates especially it can save a lot of wear over time on start up and stand up to tougher driving conditions that break down regular oil when used for extended intervals. The state vehicles in our state have been on a 10k synthetic diet for manny years and it has saved taxpayers lots of $$$$$$$ in longevity and costs. Motor break downs attributed to wear on these high mileage vehicles, just doesn’t happen according to workers I personally know. No hype, just fact.

@MikeInNH‌ ( no manufacturer has different oil change intervals…) Have you read your own Highlander manual ?
Congratulations my friend…Now you know; Toyota uses different oil change intervals for each and highly recommends that if you have to use regular oil, after 5 k you go back to 10 k synthetics ASAP ! Now, if this were Yugo I might be incline not to trust them. But as YOU know personally, their motors have exc. longevity reputations and they will do nothing to tarnish that reputation.

I use half regular and half synthetic when I change the oil. Then in between I use mostly regular.

I noticed my mpg going up a couple mpg after I started using it. I don’t think it’s my imagination. Also many people comment that the engine sounds very smooth. It’s a foreign car though, maybe that’s what it is. I do notice that many car’s my cars age (19 years) sound like metal on metal…but that may be because many of them are domestic, whereas mine is a Toyota.

I noticed my mpg going up a couple mpg after I started using it. I don't think it's my imagination.

I do. There have MANY controlled tests using synthetic…and the BEST was using full synthetic in everything (engine oil, tranny fluid, differential gear oil) and even they only saw an increase of less then 1mpg. You really need to take accurate long term documented readings to really make that statement.

Well I measured it every tankful from before I did it to afterwards. It also depends on how many miles per gallon a person gets. My mileage went up from about 33 to about 35. If it went up from 12 to 13, that would be a bigger jump percentagewise.

Gee, while they say these are compatible, why would you tamper with oil and make your own mix . Just stay with synthetic, go to a longer interval that makes your costs equal and enjoy ALL of the advantages; unless of course you have a engineering degree.:wink:

I’m not really tampering with it. Mixing it isn’t tampering. I change it at 6 months (which is also about 5K miles) so I can’t really extend the intervals any longer.

You can if you use straight synthetic. …legalistically, at least to 7500 miles. I would not feel comfortable “mixing oils” on a regular basis, especially regular and synthetics. Diluting the synthetic on a regular basis for example, IMHO, is tampering with the overall intent of an oil. I don’t feel it will perform optimally.

I’ll agree that continuing to use the correct non synthetic oil and changing at the mileage recommended for normal service, even up to 7,500 miles would be your best choice. Keep the crankcase vents free and the air filter clean and the engine should give good service for many more miles. Do check under the hood regularly though.

If someone wants to mix, there are a number of ‘blends’ available, no need to concoct your own.

I am a big supporter of synthetic oils, in everything. I don’t use dino oil in my air-cooled lawnmower. Like @dagosa, I have real hands-on experience using synthetics. Rebuilding race motors that have experienced very high oil temps (300 F) and very harsh conditions. Conventional oil doesn’t get the job done.

1 year change intervals on 7000 mile per year street cars show clean dipsticks for 6 months. Inside the engines after 100k miles look clean as new. All have improved mileage by about 1/2 mpg just with the oil (and I’m OCD about checking mileage) Do your extended changes but I would change at 9000 miles rather than 12,000.

Ignoring any hype, 22, 9000 mile oil changes costs a total of $1666 at $75 per change for 200,000 miles. With conventional oil at $25 per change each 5K miles, the total cost is $1000 for 200,000 miles.

Less than 1/5 the cost of a new engine; $666 savings with dino oil. 1/2 mpg and 89 less quarts of waste oil and far fewer hours spent with an oil-change place trying to sell you wiper blades is the benefit of synthetic.

Now you know; Toyota uses different oil change intervals for each and highly recommends that if you have to use regular oil, after 5 k you go back to 10 k synthetics

Almost all Toyota engines now recommended oil viscosity is 0w-20. That oil comes ONLY as synthetic. My owners manual says if I can’t find 0w-20…then I can use 5w-20 (synthetic or regular dyno) and then only keep it there for 5k miles. As long as using 0w-20 then the oil change interval is 10k miles.

And personally I don’t care if it’s Toyota or not…I’m NOT going 10k between oil changes. I spent too much money to experiment. I know that a 5k oil change interval works…and that’s what I’m sticking with.