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Synthetic oil means I can go a little longer right?

Car: 2007 Corolla CE
Manual States: Oil and filter should be changed every 5,000 miles or 6 months. No mention of a severe service schedule.
My Oil Change Plan: Change oil twice a year, once at the start of spring around March, and once at the end of summer around the end of September or October. I do mostly city driving accumulating about 12,000 to 14,000 miles a year. I generally drive pretty gently for fuel economy reasons but also because this car does NOT handle well at higher speeds thus discouraging spirited driving.

So, that’s 6,000 to 7,000 miles per oil change and I use Mobil 1 0W20 Synthetic oil. Right now, it’s around the 5,000 mile mark I am getting jittery and wondering if I should change it but that would throw my plan off…

What do you think? Synthetic should mean I can go 1,000 to 2,000 miles longer right?

No. Personally, I would never go 5k miles between oil changes when the bulk of the driving is city.
Generally hidden somewhere is a notation about severe service and this covers about 99% of the vehicles on the road.

State of tune, gasoline quality, the environment, the crankcase ventilation system, etc, etc. all play a part in oil life and all of those have an affect on the oil whether it’s synthetic or not.

If you’ve heard about oil sludging you should be aware that it is caused by not changing the oil often enough even though oil sludge complainees and class action lawyers disagree with that statement.

No. What the owners manual states is the proper way to maintain your vehicle. Does the owners manual mention anything about extending oil change intervals if synthetic oil is used? No!

The manufacturer of your vehicle ran the engine on a dyno. And I’m positive when they ran the engine on the dyno for testing, they also ran synthetic oil in the engine to determine if there were any benefits in using synthetic oil. And if there were, it would be mentioned in the owners manual.

Remember. The people that say you can go longer between oil changes with synthetic oil are the ones who sell the synthetic oil. Not the manufacturer of the vehicle.


The only true way to tell that it okay is send a sample of oil to a place like this

The 6 month/5000 mile recommendation is to cover all bases which it misses a few who drive really short trips in city etc, don’t top/check oil or live in incliment places. If you are under factory powertrain warranty (not much longer) they can deny a related claim on long oil change intervals.

My car a Subaru Legacy (turbo) actually stated 6months/7500 miles on dino with a turbo motor. Low and behold I got a letter a year after ownership stating use 4months/3750 miles irregardless of driving style with the engine and Subaru reverted. I am thankful I have stuck to a 3k-4k oil change since new and have 115k trouble free miles on the engine of a turbo Subaru.

Oil is cheap. Engines are expensive. Capisce?

The change interval specified in the manual is REGARDLESS of oil type. You’d be taking a very expensive risk by stretching the change interval past the specified mileage/time.

Not worth it in my opinion.

No, I would not extend my oil change intervals past what the owner’s manual recommends, even if I were to use synthetic oil. Forget about changing it twice a year, and just change it every 5,000 miles.

It’s pretty easy to remember to change the oil whenever the odometer reaches a multiple of 5,000.

My friend OK4450 is a little more cautious than I am. I change the oil in my 1998 Honda Civic every 5,000 miles. My daily commute is about half stop-and-go and half highway. My owner’s manual has two maintenance schedules. The “severe conditions” schedule recommends a 3,750 mile interval, and the “normal conditions” schedule recommends (if I remember correctly), a 6,500 mile interval.

No. This is a common misconception about synthetic oil. Never extend your oil change interval because it puts your very expensive engine at risk.

I’d change it according to the manual.

Maybe maybe not. Take your choice. On will cost you the price of an oil change (really cheap if you do it yourself) the other may cost you a new engine. Making the wrong decision could cost you a new engine.

Extending your oil change intervals means you get more mileage out of your oil.
Changing your oil on schedule (or more frequently) means you get more mileage out of your engine.
As Mleich pointed out, oil is cheap, engines are expensive.
You choose.

I guarantee that the owners manual doesn’t give different oil change intervals for regular dyno or synthetic. In fact if the car is under warranty and you extend the oil change interval even if you use synthetic you could VOID the warranty.

There is a bulletin from Toyota saying NOT to use 0w-20 oil with this engine (1zz-fe).
Do a google search for “0w-20 in 1zz-fe”.
I know this because the same engine is in my 2006 Matrix and I’m considering using a lighter synthetic oil in it this winter to see if it saves gas.
If I do it will be 0w-30. Up until now I’ve used 5w-30 dino oil, as the book specifies.
I drive ~4000 miles a year so I change the oil twice a year, in April and October.

No, no, no, no, no.

Actually it depends on which Mobil1 you use. It difference isn’t synthetic or mineral oil, it is the chemicals they add to prevent acidification of the oil. If you use Mobil1 Extended Performance, you can let it go longer. Otherwise, I’d stay to the Toyota recommendation.

OTOH, I would not pay extra for synthetic oil. Just use regular old mineral oil and change at 5000 miles or 6 months.

When synthetics first hit the market (we are talking 30 years or so ago) the main selling point was longer intervals between oil changes. Well a few blown motors was all it took to back off that claim. Synthetics are “slipperyier”, don’t shear in the heat, and hold up well in very tough applications. But, can you increase your change interval? At this point the synthetic manufacturers aren’t going to replace your engine, so increase the interval between oil changes at your own risk.

After years of guessing here on oil changes – and much of what you read is guessing – in 2009, I let my 2002 Sienna, had around 150,000+ miles, I forget exactly, go 8800 miles on Mobil-1 Extended Performance and had it tested.

On my car, mostly long distance highway driving, and motor in good shape, at 8800 miles, all parameters were still a-okay. Probably good for around 10,000 miles. Not the 15,000 miles they advertise.

Different driving pattern, or motor not as good shape, obviously the results will be different, period.

I will say, in partial agreement with them, three things.

  1. When your car is under warranty, follow the manufacturer’s recommendations, period. Essentially, that is a price of the warranty. And, do be honest about the severe driving conditions clause.

  2. Oil is cheaper than motors. If you do not wish to test your oil, follow manufacturer’s recommendations.

  3. If the current plan got your car this many years, it probably is a working plan. Why change now?

However, I do disagree with something that is often said here, that synthetic oil serves no benefit for ordinary drivers. A while back, I spent an hour or more Googling on sludged motors and only one person agreed with that. In fact, it is standard advice to use synthetic oil to at least reduce the chance of sludge.

If oil is cheaper than an engine, synthetic is also cheaper than a sludged engine. the difference in cost over the life of a car, between synthetic and dino oil isn’t that greatt.

irlandes, are there any current models out there, other than the Toyota Camry and Sienna V6 of 9-16 years ago, that are known to have sludge problems when the oil is changed at the manufacturer’s recommended intervals?

Yes, synthetic oil can address sludge problems, but how many properly maintained cars made in the past six years have sludge problems when the oil is changed on time?

@ Circuitsmith
" . . . I’m considering using a lighter synthetic oil in it this winter to see if it saves gas. "
“If I do it will be 0w-30. Up until now I’ve used 5w-30 dino oil, as the book specifies.”

Why not just go with 5w30 synthetic for the winter ? My GM cars spec 5w30 dino and call for 0w30 dino or 5w30 synthetic for extreme cold (-20F and below weather like we get here) weather operation. We get many days below -20F and lots near that.

A long time ago, I just decided to run 5w30 fully synthetic Mobil-1 Extended Performance, year-around in our cars because of the cold weather benefits and because I don’t want to be caught with the 0w30 out of season and just don’t like screwing around remembering and switching, etcetera.

From everything I’ve read the 5w30 synthetic flows much better at cold temperatures than the 5w30 dino so I don’t see the need to go 0w30. That’s why GM recommends it, I’m sure. I feel better when we have to crank the engines up to get to work and it’s colder than a well digger’s rear-end.

I still change our cars’ oil at 5,000 mile intervals, even with the EP. I always try and err on the side of caution. My wife’s car has OLM and it often reads around 35% - 40% life remaining when I pull the plug.


From everything I’ve read the 5w30 synthetic flows much better at cold temperatures than the 5w30 dino so I don’t see the need to go 0w30.

I’ve been using 5w30 synthetic for over 10 years now…Great for these NE winters…or during the summer when I’m towing our camper.

Consider the cost. How much does an oil change with standard oil cost vs the same oil change with synthetic. Now add up the cost of using synthetic vs standard oil. Is there really a material difference? I doubt it. Synthetic will be a little higher. but you will be getting a little better mileage with synthetic. The life of your car will be