More On OW20 Oil Confusion

We're going to have to wait for a European 2010 model owner to chime in. Again, I went to the BP site for the UK, their primary recommendation now for the Gen2 Prius is Castrol Edge 0W-30. They used to recommend a BP 0W-40.

 

I understand what you are saying, but i will again say the 0-20 w oil is not as good as the 5-20 or 0-30w for most Prius owners who like me dont live in Canada, even then I would recommend running a different grade in the summer and winter if you do live in the climate extremes that require it. Most of us in the USA dont need it.

Toyota is sacrificing engine life in favor of fuel efficiency and not for the customer but so they can meet higher CAFE goals IMHO. Thats why it is ok to use 5-20w in an emergency if you switch back, if it really was bad for the engine then it would not be acceptable at all. I bet if you read thru the CAFE regulations you will find a reason allowing for the the temporary departure from the oil used in the CAFE fuel efficiency testing.

My 08 Lexus RX400h has a similar requirement except it just recommends 0-20w as the recommended oil but adds the 5-20w is an acceptable alternative without the added stipulation the you must use the 0-20w on the next oil change. So I believe on the 2010 they took the next logical step in their favor. Anyway I still will go with my opinion that the watery 0 weight oil doesn't do as good a job as the heavier oils and the only advantage it provides is to the car companies in meeting CAFE fleet goals and targets and help them with their lower mileage vehicle sales. I sincerely believe it's not what is best for the customer.

 

From memory, there's a descending chart on the Service Data Sheet showing 0W-20 as the highest preference but carrying all the way down to 15W-40. Unfortunately you have to pay to even get access to that on the Toyota Europe TechDoc site. I may have saved it on my home computer but don't have it here.

Thinner oils are needed to get into tighter tolerances properly.

 

I was not too inclined to follow your recommendation, here, because it really didn't appear to be answering my question. Still, I thought I would go back and read the entire article to which you provided a link in your first post. The article was entitled SAE 5W-20 Motor Oil, and it started with these statements:

"Should you use it in your vehicle?
The answer is simple:
You get about 1% better fuel economy, but you get 30% shorter engine life !
The above statement is based on real life experience and is comparison to SAE 5W-30 Motor Oil."
​

I then read through the article and went to the end, where you thought there may be something applicable to my question about recommendations for uses in other parts of the world. What was discussed was why, in the author's opinion, Honda and Ford recommended 5W20 oil for their new cars.

I did find the following discussion, which I believe is instructive and informative:

"OK the final scoop on SAE 5W-20 and SAE 0W-20 oils:

You will definitely get better mileage with SAE 5W-20 then SAE 5W-30 oil, but not by much, usually the optimistic estimates are LESS than 1%. The bad news is about 30% reduction in engine life (from 100,000 miles or 10 years to 70,000 miles or 7 years).

Only manufacturers who have 3 years or 36,000 miles powertrain warranties currently recommend SAE 5W-20 oil to be used in their NEW 2000 through 2006 model vehicles (FORD, HONDA).

By contrast Mercedes-Benz that offered 4 years or 50,000 miles warranty not only specified SAE 5W-40 motor oil, but in the USA, to assure that only that oil grade was used, provided periodic maintenance FREE to all its customers. (Free maintenance was offered by Mercedes-Benz from 2000 model years through 2004 model year, it was cancelled on 2005 model cars and SUV's)

ALL heavy-duty engine manufacturers recommend SAE 40, SAE 15W-40 or SAE 5W-40 oil.

FINAL choice is yours, you can get BETTER mileage, or LONGER engine life.

If you are leasing a vehicle, then the BETTER mileage parameter is definitely more important as well as cost effective. You just do not care how long will engine last on a car that you will only operate for 24,000 to 36,000 miles. But how many Gallons of fuel you will burn will make a difference.

If you own your vehicle for the long haul, or indefinitely, then SAE 5W-50 is absolute must!

That is why SynLube™ Lube-4-Life® is available ONLY in that grade, since we guarantee 300,000-mile service life from engines that were engineered to last no more than 100,000 to 150,000 miles. It makes that much difference!

But due to unique colloidal technology used in SynLube™ Lube-4-Life® you still get mileage benefit that is 1.6% to 2% better than even SAE 5W-20 petroleum motor oils that are now used by OEM’s.

So with SynLube™ Lube-4-Life® you DO NOT have to sacrifice engine life to get BETTER fuel economy! You get both: lower fuel consumption AND longer engine service life!"
​

So the end recommendation of the article is this: Don't use 5W-20 motor oil in your car unless you want to damage the engine. Instead, use OUR 0W-20 synthetic oil, because it will not only give you better fuel economy, but it also will protect your engine better than 5W-50. This entire piece is a marketing and sales effort. It doesn't offer any real data -- only sales hype.


What I really take away from this is the following:

1. SAE specifications have very little to do with quality -- only wide-ranges of viscosity.
2. Synthetics may offer quality differences.
3. Different engines and different driving conditions require different oil qualities.
4. Snake oil can come in all different weights.
5. I think I knew this before.

We still have a real debate over the "need" vs. the "requirement" for numerous (i.e. frequent) costly oil changes using synthetics.

 

I'm more than honest enough to admit that 0W-20 isn't for everybody. There are a lot of motors I would never use a 0W-20, or a 5W-20, in , except strictly as a cold weather oil

However, after putting on around 70,000 miles on my '04 Prius, with routine used oil samples and a few filter samples for giggles, the end result of running Mobil 1 0W-20: lower than average wear, across the board for me

Now, despite Toyota now recommending 5W-20 for the FJ, I discovered my FJ motor does NOT like 5W-20 or 0W-20: nitration spikes, TBN gets used up. I've had the best readings with that motor when I run Mobil 1 European Car Formula 0W-40

I have no doubt the xW-20 oil requirement by Mazda, Ford, Honda, Chrysler, and now Toyota are to earn EPA brownie points. The average driver will *never* notice any difference in fuel economy

However, if the motor is well made, there should be no impact on durability. If you intend to go for extended oil changes like common in the EU, a well made 0W-30 or 0W-40 is required

 

Make of this image, from the EU Service Data Sheet, what you will:



I honestly can't work out what the preferences are. Up to 20W-50? Ridiculous. That's practically sludge before it goes into the engine. Sounds like we're going to have to be very specific about getting 0W-20 if we want that.

(I've attached the original PDF as well.)

 

Mike

Thank you for looking into this.

It would have been helpful for Toyota to have temperature ranges for the viscosities listed. I went to the BP site for the UK, and their primary recommendation for the GenII Prius is Castrol Edge 0W-30, with 15,000 km or 12 month service intervals

According to the BP Lubricant Advisor page, alternate oils are a 10W-30 if the temps are never colder than -18 C. A 15W-40 may be used if the temps are never colder than -12 C. A 20W-50 may be used if the temps are never colder than -7 C

I then thought I would check with a Ford Focus, as this model car sold in North America requires a 5W-20 oil. The BP Lubricant Advisor recommends the Castrol Magnatec A1 5W-30, with 12 month or 10,000 mile oil change intervals. Castrol doesn't appear to even market a 5W-20 in the EU

I then checked the current model Honda Civic. BP also recommends Castrol Edge 0W-30

I checked with Mobil UK, but they don't appear to offer a similar lubricant advisor page

 

Well I for one just don't like getting raped by Toyota so they can get better CAFE number help. The best oil for the Prius in my opinion would be a HIGH QUALITY 0-30w synthetic that can be left in for 12,000 or so miles. Or for that matter Mobil 1 0-40w European formula and longer oil change intervals. This would provide better life expectancy for your engine and save you money in the long run for service too. i don't get this 6 month or 5000 mile engine if Toyota is actually using a full synthetic 0-20w.

 

Just for kicks, I asked the guy's at Bob is the oil guy about this. I didn't get the answer I expected oil for Prius - Bob Is The Oil Guy

 

That squares with the 5W-30 recommendation from Toyota, and the service interval. Of course getting the dealers to do it right is another issue...

We've had temps down to -4°C this winter, where I live, but it doesn't often get that low.

I'm not sure how comparable these cars really are, because the engines, in the Focus at least, are completely different between North America and the European versions. (They're both badged 'Duratec' now but Ford of Europe's designs are their own, not derived from Mazda's.) I also don't remember the oil on my 2001 Focus being as light as 5W-30, though I didn't change it myself.

 

Thanks for the link. A very interesting read.

The one thing that is missing, though, is a statement that oil changes at only 5,000 miles using 0W-20 would be a ridiculous waste of oil.

Perhaps the focus in that forum is premium engine operation and life expectancy -- not eco-sensitivity.

 

Want to bet that they would tell you that using a pure synthetic in a Prius and changing it more often than once a year and or 12,000 miles is pure folly? I bet something along those lines would be the answer.
Heck, I'll ask that question

 

I took a trip to walmart and they only had mobil1 5w30 and 0w30 and a bunch of 10w40's. Is it okay to use 0w30 instead?

 

"Probably 12-15k miles easy on ASM or M1."

Only answer I got so far, They are just like over here, if most agree, nobody posts, but if most think his answer is wrong, well they will be all over him.
This post is also interesting, and enlightning, at least for me. Toyota admits that thin oil is not for everyone. - Bob Is The Oil Guy

 

Must be nice. I personally don't like -40 weather. I have an insulated and heated attached garage for a very good reason

I looked into it some more and BP does *not* offer any xW-20 oil in the EU. The Mazda models sold in the EU appear to require either a 0W-30, 5W-30, or 0W-40 oil, depending on model and expected ambient temperature

Ok, correction, they offer a 0W-20, but only as a *racing* oil. They don't recommend it for the street!

Of course, it could be that Mazda uses different engines in the EU vs North America

 

Thanks for asking.

So we now have plenty of people saying that the 0W-20 oil (assuming it can only be found as a synthetic) should be fine and not threaten the engine's lifespan. We still have the same question: Why require 5,000 mile changes if we are using such a top-grade synthetic oil? For the expense involved and the reliability of the oil, isn't it just a simple waste of resources to require twice as many oil changes as may be necessary?