Confuse about Oil Change

Use 0w-20 synthetic and change it every 10,000 miles. If you are in a pinch, or your city is closed off due to riots and you have no access to 0w-20 synthetic, then change it every 5,000 miles with what oil you can find that is close.

 

Here we go, I'm about to get some flack over this, but once my warranty period is over, I'm going back to twice a year oil-changes. The reasons for changing oil are: accumulated contaminants, acidification and loss of lubricating qualities. Regular oil has lubricants in it; synthetic oil is a purified form with enhanced lubricating qualities added. Engine wear is caused my metal-to-metal contact. This happens when the oil fails to form a barrier between the metal parts, either from pressure, heat or breakdown of the oil. Synthetic oils in my experience, practically reduce engine wear to zero.

Personally, I think the dealer's recommendation to change my oil every 8000 kms is overkill, but it's free, so I'll continue to take advantage of it.

 

I use a 5,000 mile periodicity.

 

First a good synthetic oil is not necessarily better than a good conventional oil......it just lasts longer and can be made stable at thinner grades.
A good conventional oil of say 5W30 grade would be fine but your gas mileage might suffer a tiny bit.

Second, the maintenance reminder pops up every 5K miles because of the recommended tire rotation interval AND for those who need it for oil changes.......severe service or conventional oil.

I elected to do my tire rotations AND synthetic oil changes about 10K miles after my first one at 5K which has already been done.
Therefore I will be resetting the reminder when it pops up at 5K.
There is no substitute for the little window sticker, IMHO.

 

I just scanned my pdf of the Prius C Owner's Manual, and couldn't find the word synthetic. D.O. for the Warranty and Maintenance Guide. Where did you see this stipulation to use different interval for regular vs synthetic oil? Also, are you in the 'States?

FWIW, I don't think you get non-synthetic OW20.

In Canada, the interval is 8000 km (roughly 5000 miles) or 6 months, whichever comes first. The oil spec is 0W20, no mention of synthetic or regular.

 

Guess the Canadian environment is considered "severe service."

 

I don't think I'm wrong in saying that a 0W20 oil is the best of all worlds. It reduces internal resistance due to viscosity at all temperatures, therefore helping improve fuel economy.

 

Absolutely right. That's why there is no mention of a conventional 0W20 option because that does not exist.

 

You're correct....

 

Here's what it says in the 2012 manual for the C:

Recommended viscosity: SAE 0W-20.
SAE 0W-20 is the best choice for good fuel economy and good starting in cold weather. If SAE 0W-20 is not available, SAE 5W-20 oil may be used. However, it must be replaced with SAE 0W-20 at the next oil change.​

 

Never say never (or always.)

If my understanding of oils as lubricants is somewhat correct, viscosity is a trade-off: higher values give more protection against wear but have higher heat losses. So while I am more than fine in following Toyota reccs as a run-of-the-mill owner, I can imagine situations where a different oil spec would be better. For one, running the engine hot by running up and down mountains every day; or 2, trying to prolong the engine life way beyond the Toyota spec.

 

Not "heat loss." Higher viscosities create more friction and higher heat retention.

 

Synthetic vs. Conventional Motor Oil: Which is Best for Your Needs and Environment's? - HowStuffWorks

I believe that using synthetics allows you to have the best of both worlds.

 

Thanks for the input as I am a new owner.

 

I haven't seen a conventional 0w-20 yet. They're all synthetic AFAIK.

I change mine at 5k mile with synthetic, though I have synthitic 5w-20 in it at the moment.

There are no absolutes in what to use in your sump. Any grade is a trade-off between something or other. Learn about it and make an intelligent and informed choice.

 

I've never heard of a 0W non-synthetic either. I believe it's only possible to make such an oil using synthetics.

 

Just do what your respective years manual instructs you to do.
I have only one instruction that I act against and that is the 10000 mile interval.
I refuse to go that far. I bring my oil and have them exchange the contents in the Prius. Filter also.
Your air filter is quite significant in all this. I do that at 3000.
I can live with the overkill practice if that's what one might call it but only in recent years have 10000 mile intervals popped up. I benn changing at 3000 in carollas and tercels long ago. Synthetic that is. I have had amazing reliability. One vehicle lasted 10 years and went strong with teenager abuse for the last 4 years and sold it running strong.
10000 is not in my comfort zone. I think they get more repeat buyers overall with that policy

 

I really hope that you don't change the air filter every 3000 miles too.
Both are not just overkill but totally lacking in anything close to a factual need.

Even before synthetic oil came into wide use, several car makers were recommending 7K changed with conventional oil.
You are TOTALLY ignoring advances in oil chemistry and engine design and I don't think that is smart at all.

A 7K interval......or even 5K......sure but 3K is just gross wasteful overkill.
Same with air filters which should look like new at 3K.
What you are doing is just simply a total waste of time and money.

 

My engine air filter looks like new at 48000 km and 4 years. Maybe the rainfall and damp here, keeps the dust down? I just put it back in, no point to replace it. Expensive too.

Maybe SLim meant 30,000?

It does depend on your environment a lot though. A lot of driving on dry dirt roads?