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Oil change interval

Just received notice from Toyota that our 2010 Prius does not need to have its oil changed @ 5,000 miles/6 months. We can wait another 5,000 and only need to change it at 10,000 mile / 1 year intervals. This vehicle reuires very pricey 0 W 20 synthetic. Does this new recommendation seem reasonable? I’ve never gone beyond 5,000 on my other autos.

Did the dealer tell you in person, or did you get some kind of technical service bulletin in the mail?

Just do what the owner’s manual says, if in doubt.

These things have been vary reliable and there is no reason not to trust the manufacturer who has to support the warranty . If that’s the case, I would go by the “new” recommendations; then the oil will cost half as much.

it was sent in the mail and included a revised owners maintenance manual stipulating the new 10,000 / 1 year oil change interval.

Agreed, what the o.p. got in the mail basically just amends the owner’s manual, so he or she should have no problems with that maintenance schedule.

This sounds reasonable, since the factory is using a fully synthetic oil. This was the main reason that synthetics were developed. To hold their lubricating properties longer than conventional oils and extending oil change intervals. Since this notice is from the manufacturer, not dealer advise, I’d find it very reasonable.

Mmmmmmm…I just get the creeps about having oil in my engine that long. I guess since its synthetic that is something. But if you actually do the math the cost over the life of the auto will not really be that much.

As for the warranty business. A car company only cares if you get past the warranty period. At most this is 100K for the motor. These days you can actually abuse an engine and get 100K out of it. But at 100K I’m thinking I’ve just gotten it broken in. (Actually the last 3 vehicles I’ve bought have had over 100k when I bought them). I need a lot of miles after that.

So really, I would ask yourself this. At about 100k miles are you going to be looking for a new car anyway? If so, just follow Toyota. If I were standing at the beginning looking for an indefinite ownership period/number of miles I’d err on the side of caution and probably not go 10K between changes.

I would definitely go by Toyota’s new recommendation with the caveat that 10,000 miles is probably for less severe environments. If you drive in a sever environment, you should change more often. Make sure that the synthetic oil has increased additives to prevent acid formation in the oil. Just being synthetic doesn’t prevent acid formation. Mobil 1, for instance, has several blends. They say that only Mobil 1 Extended Performance is guaranteed for high mileage between changes.

Oil gets contaminated at pretty much a constant rate. As engines age, blow-by increases and the oil becomes contaminated quicker. There seems to be a backstage “movement” to reduce the amount of drain oil disposal services and facilities must deal with. Synthetic oil has NO built-in ability to absorb 3 times as much contamination as mineral oil. By itself, it is not an outstanding lubricant, no more so than mineral oil…

I feel bestowing these unearned powers on synthetic oil is misguided. It was developed to take advantage of its broad temperature range, it’s ability to hold it’s viscosity over a very broad range…It excels in arctic conditions…

So if you feel your car can suddenly go two or three times the former recommended distance between changes, go for it…It will be the next owner who finds out whether this was a wise decision or not…If Toyota thought they had trouble with engine sludging before, this should be an interesting experiment…

Having said that, one has to assume that manufacturers have been able to improve ring seal over the last 100 years…As this seal nears 100% efficiency, the need for engine oil changes evaporates as there is no longer any crankcase contamination…Engines will be “lubed for life” and the oil change threads will finally disappear…

The Prius motor is set up to run at its most efficient. It does not generate as much internal pollutants as well as very little external pollutants. One year or 10K miles with a pure synethic seems fine with me.

If you go with the longer interval, don’t forget to check/maintain the oil level on a regular basis.

Ed B.

If you go with the longer interval or if you don’t. follow the longer interval, be sure the check the oil level on a regular basis.

The rationale (partial)is that the Prius engine works only half as hard due to the hybrid system, and therefore can go longer between oil changes. A small part is due to the fact that it is synthetic. I have a Toyota and have received factory bulletins that 5W20 regular and 0W20 synthetic is now OK. But not a word about increased drain intervals.

A 0W20 oil HAS TO BE SYNTHETIC, there’s no way to make a good 0W20 il from regular mineral oil base stock.

An additional reason for going to 10,000 miles is that maximum fuel mileage (which is the Prius selling point) benefits from 0W20 oil, but it’s expemsive, so you won’t balk at having to change it every 5000 miles.

If this whole thing smells of smoke and mirrors to you, that’s EXACTLY what it is. Manufacturers want to squeeze every last fraction of a mile per gallon out of the car, and going to thin oil helps. But oil that thin has to be synthetic and expensive. So we stretch the mileage interval to change it to compensate.

Would I change oil every 10,000 miles if I had a Prius? Not likely, I would stick to 5000 but would use 0W30 synthetic oil to maximize engine life.

In their regular cars, Toyota used to recommend oil changes at 8000 miles. After sludging became an issue they reduced that to 5000 miles for all types of driving.

10,000 miles is easy enough with a good synthetic. This naturally assumes a well designed engine and that the service is conducive to 10k mile oil changes. It surely wouldn’t be sensible for someone doing 5k/year unless all 5k of it was some 100 mile event once per week.

The hybrids confound the meaning of mpg. I’d put an hour meter on the engine to really determine the usage. From what I can figure, there’s no solid metric other than calculating fuel consumption (not miles/fuel added or MPG) …but just xxx amount of gallons added. This should give you an absolute measurement of engine usage. YMMV due to the hybrid’s features, but fuel consumed will always equal engine load/time operating.

My only feedback is go with your gut.

Subaru stated 7500 mile oil changes were fine using conventional oil with my 2005 Subaru Legacy turbo car. Low and behold in 2008 I get a letter highly recommending using 3750 miles as oil change interval and Subaru reverted all new turbo cars to the severe interval.

Toyota is not star, they screwed up oil change intervals. They had a plethora of engines sludging themselves in the early 2000’s model years due to design flaw and elongated oil change interval.

Good point; industrial engine manufacturers used to recommend oil change itervals by operating hours. Now, Caterpillar and others recommend changes base on pounds or gallons of diesel fuel consumed, which makes sense. The hybrid engine has lower fuel consumption than a similar non-hybrid. So, theoretically if it gets 30 % better fuel mileage than a simlar non-hybrid car, you could lengthen the oil change interval by 30%. But not 100%!!!

The automotive engineers who work in laboratories and wear white or blue shop coats have no clue as to real world operating conditions. They live in their own dream world and can get into the bad habit of believing their own BS. They think their creations and recommendations are PERFECT until the warranty claims start pouring in…Use a little common sense and you will be okay…Dirty oil LOOKS LIKE dirty oil! Change it! Is that so hard to do???

Been running synthetics for 15,000 miles plus since intro of Mobil 1 in the 70’s, without a hint of a problem.

On most cars with some miles on them, the oil gets dirty at about 1500 miles. It does on my Nissan and is a result of the combustion process. Oil is supposed to go dirty as carbon is rejected by the engine. Om my newer Toyota, the oil stay clean, like maple syrup, for about 3000 miles, then starts to darken. It all means, in both cases, that the oil is doing its job properly, by holding all this stuff in suspension instead of letting it coat the engine and form sludge.

Having said all that, there are many other additives in the oil that get gradually depleted. I would only extend the drain interval if I had the enchanced, long life MObil 1 in the crankcase. This oil allows 10,000 miles drain intervals under normal (easy) coditions. The “severe service” factor will always apply; cut the interval in half if you do strenuous city or severe weather driving or have high engine loads.

I’ve read and seen all the justifications and they make sense, however I personally would not sleep well pushing my oil changes to 10,000 miles. Granted, synthetic is expensive, but I keep my cars forever and want the engine sto last forever. Oil cannot be too fresh, only too old.

In summary, I would not criticise those who follow the recommendation, but I personally would stick with 5,000 miles.