Toyota oil vs Mobil One oil

I'm not sure what the differences are between Australian and US conditions but the oil used by my dealer here in Australia is 5W-30. The manual indicates any of 0W-20, 5W-20, 5W-30, and 10W-30 API grade SL or Energy Conserving, SM Energy Conserving or ILSAC multigrade engine oil. page 280 of the Aussie manual.

 

When it really comes down to it, ANY multi-vis oil will probably work just fine. The question is (regarding weight) whether it will be optimum for the operation of the engine. I can see getting a little better mileage with the thinner oil, and that's probably why Toyota recommends it.

I also wouldn't put it past Toyota to have conveniently changed the oil change interval from 5k to 10k when they decided to implement Toyotacare .... so they only had to pay for 2 oil changes instead of 5. Notice they didn't go to 30K or do what most other companies do ... up to 36K when the warranty is up.

In reality, 10K on any modern synthetic is nothing to worry about. Over the road trucks go 20-25K regularly without oil changes, and Europe has been going 15K for decades in their cars. The old 3K oil changes were just a waste of oil. 5K probably is too.

I'd use whatever YOUR manual states.

REV

 

However two recent posters with sensitive ears (one here, one on Gen2) are saying after 4-5K miles they are hearing noise due to valve covers losing lubrication. The poster here is saying if he uses expensive Amsoil for $10/qt it solves the problem. Couple questions, does anyone care about valve noise? Is this due to fuel entrainment causing lower visc? How about add 3-qts at first refill and add some new oil (heavier visc) at 4K miles?

 

Here is a photo of a page from the Australian Gen3 Prius owner's manual. Same car with the same engine we have. 0W20, 5W20, or 5W30 are recommended for any temperature and 10W30, 15W40, and even 20W50 at warmer temperatures. This was posted by an Australian Prius owner on another oil viscosity thread a couple of months ago.

I believe the main reason Toyota recommends/requires only 0W20 oil in the U.S. is because of the EPA regulation requiring only the oil used for tests be recommended to the customer.

This discussion about which brand of 0W20 is best or thinner seems rather irrelevant considering the minor differences in the two (Mobil 1 vs Toyota 0W20) compared to the large differences in viscosity listed for Australian owners with the same car. I am still using 0W20 Mobil 1 but I sometimes wonder if a higher viscosity, such as 0W30 or 5W30, might be better for summer?

 

Exactly my point TW !! Bottom line is .... It simply makes VERY LITTLE DIFFERENCE. If you think you hear valvetrain noise, and you feel that you need $10 a quart Amsoil oil ... then buy the damn stuff. For the rest of the world, any 0-20 Synthetic will be just fine. Nitpicking about minute differences in specs that vary by 5% or so just won't fly with most owners who don't have their oil analyzed by NASA.

Regarding using a heavier oil in summer ... I think these engines are so tight and of such high quality, that I'm going to stick with the Toyota America recommended 0-20 Synthetic made by any old quality oil company that I can find on sale. Mobil One, Quaker State, Pennzoil, Castrol .... whatever. It'll all work and the car won't know the difference. If you DO try the heavier oil, it would be interesting to know if your MPG's stay exactly the same, or if they fall off a bit due to the thicker oil.

REV

 

LOL ! The REALLY FUNNY thing is ... I posted above that you could probably use almost ANY multi-vis oil and be OK, and this was BEFORE the guy from Australia said their manual said they could use anything all the way up to multi-vis 50 weight.

This should finally put this issue to rest.

REV

 

what is valve covers lubrication?

 

I'm sure he meant valve-train lubrication, as he was referring to a previous poster who said they heard valve noise at 4-5K when NOT using Amsoil.

No big deal ... I knew what he meant, and that's why I didn't comment on it.

REV

 

You are not going to "wear out' the oil in 5k or even 10k ...30 years ago with leaded gasoline carburetors and point ignitions -- the oil would become contaminated.

Most of the contaminants are no longer a problem and the oil additives are very longed lived.


I'm not sure what people think is happening to the oil -- or the transmission fluid ... that has no combustion contaminants at all?

Something else is a problem if you have a valve noise.

 

...right, you know, valve train lubrication...we have a couple of posters saying that is a problem after 4-5k miles on synthetic oils including Mobil-1 Extended Performance (extended drain interval).

But the truth is I already purchased the Mobil-1 Extended Performance ready to go my Gen-2 Prius any day. I am planning to go 10-15k on it, so I was not too happy with the negative reports about valve noise at 4-5k. Even if valve noise happens, do I care, I am asking?

 

People say all kinds of things on the internet ... use a quality 0-20 synthetic and enjoy your car. Every little noise doesn't mean the oil is going bad.

REV

 

...OK Rev...except Gen-II uses 5W-30
I may blend in 1/2-qt heavier formula after 4K.
Not sure about Gen-III but the Gen-II lube oil gets a certain amount of fuel dilution, so I am thinking that may be why these guys are reporting valve noise at 5K. As Tumbleweed said I could even add a little 10W-30 to heavy it up.

 

As this is a Gen III forum, I didn't even consider people were talking about Gen II's.

Sorry for any misunderstanding.

REV

 

Personally, I would not mix different viscosities to try and come up with my own formula. I don't have the knowledge to know what the result would be.

But I think in the case of your '06 Gen2 you could use 0W20, 5W20, or 5W30. The chart below indicates that all of those are approved by Toyota. In addition you could use 0W30.

I always used 5W30 Mobil 1 in my '05 Gen2 Prius so I don't know if thinner oil would have improved the mileage or not.

 

It's the lifters that are making the noise. It is very typical on older cars or engine with more "aged oil". When oil gets used up, viscosity changes. There are millions of posts and questions on cold start ticks. You buy whatever you have to, but I am okay to pay $70 for a complete Amsoil 0W20 change with a TRD filter as I can comfortably do 10K miles easily. Never will I have to hear the lifters tick in the morning (remember ticking is from lack of oil/lubrication). Mobil 1 and the Toyota oil didn't do it for me.

I don't believe all oil are made the same either. I used Valvoline synthetic on my Nissan as it was on sale, yet I found that to be a huge mistake as the motor got louder within that 3000 miles. What a mistake that was.

 

Cossie1600: You are not going to exhaust the additives in synthetic oil in 10k on this Prius. If you have a valve noise on a low mile engine it is caused by a problem not associated with the oil.

Older cars can benefit from some additives -- but the additives you are speaking do not extend the life of the engine or the lifters. This is a totally different thing.

Same goes with any gasoline deletion -- this is why you need to check your oil occasionally. Although this is very rare in modern engines in temperate climates.

 

What problems did you have with the other oils?

Is your Amsoil API and/or ILSAC certified?

Are you sure Prius has hydraulic tappets?

 

I'm almost at 35K miles on Mobil 1 0W20, and I've NEVER heard valve noise or some noise that made me think the engine was lubrication-starved. Over in the Gen II thread I saw, the problem sounded more like excessive gasoline dilution of the oil rather than the oil itself failing.

 

Blackstone seems to disagree with you as they note the deterioration of the oil.

yup my engine has so much problem that it only gets the cold tick when oil starts to get past their prime and it goes away after new oil is put in. It must be magic that my "engine problem"goes away after it gets fresh oil.

your info is so accurate that my car used exactly .25 quarts of oil after 11k miles. Yeah I need to check my engine oil more often......whatever.

 

I just stopped using it when I started hearing ticking once the oil got old at initial cold starts. It was the same thing I had with my Miata, a simple change in oil brand took care of it. I used Mobil twice and Toyota oil twice

No they have regular lifters, but it doesnt mean it doesnt need oil lube