2010 Prius - What oil to slow down burn?

[uart]

Originally Posted By: 147_Grain

Let's see: The Prius uses 1 quart of oil for every 1 quart of gas. Somehow things aren't balancing out here.

Well, in all seriousness, if a Prius really did get 1000 miles on just 1 quart of gas plus one quart of oil, I'd get one in a heartbeat!

 

[Gokhan]

Originally Posted By: Cujet
There was a very interesting Prius post on another forum, from a guy switching to M1, 10W-30 to help reduce consumption. From what I remember, It worked well, the engine was a bit quieter and MPG's actually went up a bit.

He piled on the miles, and had great results.

Yes, if there is a bad valve-stem oil seal, increasing the viscosity will decrease the oil consumption. In my experience, with 15W-40, it was about one third of the consumption with 0W-20 (well, actually 5W-30 at that time) until I replaced the valve-stem oil seals. Then, the consumption stopped completely.

However, fuel economy increasing from 0W-20 to 10W-30 is plain nonsense, especially in a Prius engine. I could understand some, especially older and worn, engines having difficulty with low viscosities, but that wouldn't happen in most modern gasoline engines. People's reports of fuel economy shouldn't be taken seriously, as they have no controlled way of measuring it, especially those lacking analytic skills. Lower viscosity means less hydrodynamic friction, which is usually the biggest source of friction in an engine with conventional bearings. The benefits in fuel economy could be anywhere from about 1% to more than 5% when switching from xW-40 to xW-20, depending on how the car is driven. You will see the most benefits of lower viscosity if the car is driven gently.

Quieter is also very subjective. The sound of the engine may change with the oil viscosity but that means little on whether the engine is performing with less friction or having less wear.

 

[uart]

Originally Posted By: Gokhan

However, fuel economy increasing from 0W-20 to 10W-30 is plain nonsense, especially in a Prius engine.

Gokhan, we don't know that he switched from 0W20, I've asked the above poster for clarification on that. The recommended oil for the previous model Prius was always 5W30, so perhaps that's what he switched from.

 

[vwGLI]

i had good luck with M1 HM oil

 

[xBa380]

Thanks for all the suggestions!

Next week I will pull the plugs and check for oil on them or anything abnormal.

FWIW, the dealer did an oil consumption test and said they never had a prius burn so much, yet said according to Toyota it is in spec... Dad called corporate and they told him the same thing and won't do warranty work on it.

So he is really ready to unload it... I guess he got a very good trade in offer for it (brother works at dealership) so that may be why. He is very concerned with the motor...

I'll check the plugs though and go from there. No leaks or anything either. It is burning it all.

 

[Cujet]

Originally Posted By: xBa380
Thanks for all the suggestions!

Next week I will pull the plugs and check for oil on them or anything abnormal.

FWIW, the dealer did an oil consumption test and said they never had a prius burn so much, yet said according to Toyota it is in spec... Dad called corporate and they told him the same thing and won't do warranty work on it.

So he is really ready to unload it... I guess he got a very good trade in offer for it (brother works at dealership) so that may be why. He is very concerned with the motor...

I'll check the plugs though and go from there. No leaks or anything either. It is burning it all.


I am sorry I can't find the link to the post, I even looked in my browsing history to see if I could find it.

However, I do recall that the Prius owner went to various heavier and more robust oils in an attempt to reduce consumption and noise. And that the results reported were good.

Please, before you unload the car, try a significantly heavier viscosity, quality synthetic.

I know this, Both my 09 F150 5.4L and my 11 F150 Ecoboost have better results with heavier viscosities. Especially the 5.4L. Much quieter, smoother, no cam phaser noise, and far less consumption.

There really is no magic to engines. I'd guess it's likely that your very thin oil is pumping past the piston rings of all cylinders evenly, and consistently. Mostly due to fit and finish of the cylinder bores, not wear. I'd also guess that a switch to M1 10W-30 or M1 10W-40 High Mileage will solve the problem.

 

[uart]

Originally Posted By: Cujet

I am sorry I can't find the link to the post, I even looked in my browsing history to see if I could find it.

Don't worry, that happens to me all the time, when I know I've read something somewhere but can't find it again.

xBa380, what's the climate like in Cleveland. It's mostly above freezing from now to about November isn't it? I can't see any harm trying a heavier grade at this stage. I'd try a few runs of HM 5W30 or even 10W30 in the warmer months. BTW. Is it ever really hot in Cleveland, or was that just a dumb sitcom.

 

[Gokhan]

Toyota won't repair oil consumption unless you show them a particular engine problem. That's why you should remove and inspect the spark plugs. If there is an obvious problem (like a wet plug because of an unseated or broken valve-stem oil seal -- they are rather fragile and can easily get damaged at the factory), they are required to repair it under warranty.

If you can't have it repaired under warranty for some reason, switch to a cheap plain 10W-40 for much less oil consumption and little cost of makeup oil -- it will do no harm at all -- and keep it until the 4th-generation Prius becomes available. Then, trade it in for a 4th-generation Prius. Priuses depreciate so little that you will hardly lose any money if at all.

 

[gregoron]

My guess is that you need a higher HTHS and lower NOACK oil of the same grade first then think about going up a grade. If you do go up a grade, I'd go shorter intervals as your engine might break down that thicker oil faster. Have you been using OEM filters?

 

[friendly_jacek]

Originally Posted By: xBa380

FWIW, the dealer did an oil consumption test and said they never had a prius burn so much, yet said according to Toyota it is in spec... Dad called corporate and they told him the same thing and won't do warranty work on it.


Weird, he said (in the fist first thread):

Quote:
Car has around 70K miles on the ODO.


It's clearly past the drive-train warranty.

 

[Gokhan]

Originally Posted By: gregoron
My guess is that you need a higher HTHS and lower NOACK oil of the same grade first then think about going up a grade. If you do go up a grade, I'd go shorter intervals as your engine might break down that thicker oil faster. Have you been using OEM filters?

There is neither high-temperature nor high-shear at the valve guides, therefore the oil consumption through valve guides is controlled by the low-shear (kinematic) viscosity at around 100 C, not the HTHS viscosity.

However, if there is consumption past the rings, HTHS viscosity might perhaps be better correlated with that, as it's a high-temperature, high-shear environment like the bearings.

Lower NOACK, meaning low evaporation, will reduce the oil consumption a little but not if it's happening through the valve guides. However, unless you use a CJ-4 15W-40, which all have low NOACK but are still cheap because they are dino, low-NOACK oils are synthetic and expensive for a car that needs constant makeup oil.

Going to a higher viscosity will not decrease the oil life. In fact, for a given base-oil type, it will usually increase it, as NOACK decreases. Oil life is determined by the base-oil quality (like synthetic vs. dino), NOACK to some extent, starting TBN and TBN retention, detergents and the additive package, and oil-filter capacity. As an example, Mobil 1 0W-40 is one of the longest-life oils out there despite being fairly thick.

I checked Toyota warranty, and yes, it's only 60,000 miles. Therefore, if oil consumption is a concern with this car, simply use a cheap plain 10W-40 to minimize it. You can in principle use 15W-40 as well and go with a 10,000-plus-mile OCI with it, which is even quite a bicker than 10W-40. 15W-40 is thick, has low NOACK, and has excellent TBN and TBN retention for low oil consumption and long oil life. I would recommend Mobil Delvac 1300 Super 15W-40. Let us know how a Prius runs with 15W-40 if you do so.

Or have it fixed for about $500 - 1,000 if it's a simple valve-stem oil seal issue.

 

[steve20]

OP was the car purchased new ( less than 10 miles), used, a demo, etc? Anything in it's history to trace back to an event which may have caused the oil burning?

 

[xBa380]

Car was bought new... few miles on the ODO when delivered.

Car sees quite a bit of heavy city driving. A big reason he bought it!

I will go with PP or PU 5w30 and check the plugs prior... See if anything abnormal. My dad wants to send an oil sample to Blackstone, but not sure with all the makeup oil if it would be worth it. Thoughts?

 

[Cujet]

Originally Posted By: xBa380
Car was bought new... few miles on the ODO when delivered.

Car sees quite a bit of heavy city driving. A big reason he bought it!

I will go with PP or PU 5w30 and check the plugs prior... See if anything abnormal. My dad wants to send an oil sample to Blackstone, but not sure with all the makeup oil if it would be worth it. Thoughts?


I've been poking around Prius chat, and other forums. It seems this is not uncommon. It also seems from what I read there, engine wear is the issue. So much for a 0W-20 protecting "just as well".

I stand by my statement, M1 10W-30, as a minimum viscosity. There are prius guys that add STP oil treatment, successfully reducing oil consumption.

 

[LineArrayNut]

Originally Posted By: Cujet


I've been poking around Prius chat, and other forums. It seems this is not uncommon. It also seems from what I read there, engine wear is the issue. So much for a 0W-20 protecting "just as well".

I stand by my statement, M1 10W-30, as a minimum viscosity. There are prius guys that add STP oil treatment, successfully reducing oil consumption.


IMNSHO it's the 10K mile OCI too. False economy driven by beancounters and the drive for a couple 10th's of a mile per gallon...

 

[Gokhan]

Originally Posted By: LineArrayNut
Originally Posted By: Cujet


I've been poking around Prius chat, and other forums. It seems this is not uncommon. It also seems from what I read there, engine wear is the issue. So much for a 0W-20 protecting "just as well".

I stand by my statement, M1 10W-30, as a minimum viscosity. There are prius guys that add STP oil treatment, successfully reducing oil consumption.


IMNSHO it's the 10K mile OCI too. False economy driven by beancounters and the drive for a couple 10th's of a mile per gallon...

There is no evidence at all that 0W-20 causes increased engine wear in newer Toyota engines. 0W-20 is only slightly thinner than 5W-30. In fact, I run 0W-20 in my 1985 Corolla successfully without any wear issues.

 

[Gokhan]

Originally Posted By: xBa380
I will go with PP or PU 5w30

Why use premium oil in an engine to which you have to add a lot of makeup oil? It's unnecessarily expensive. Use the cheapest brand-name oil out there. You can even use Mobil Delvac 1300 Super 15W-40 to decrease the consumption by a factor of 3 and it will easily get you a 10,000-mile or longer OCI without any problems.

 

[Cujet]

Originally Posted By: Gokhan

There is no evidence at all that 0W-20 causes increased engine wear in newer Toyota engines. 0W-20 is only slightly thinner than 5W-30. In fact, I run 0W-20 in my 1985 Corolla successfully without any wear issues.


However, there are certainly a number of faithful Prius owners with oil consumption issues. And, in each and every case I've read about, engine wear is the issue. I'd guess that it's a really low quality engine, then...

Or could it be that a super thin oil simply finds its way past the rings of a engine with some time on it???? (this is my best guess, and that's all it is)

 

[Coprolite]

I would endorse the hypothesis that the engine spends more time in the "start up", extra wear regime where the oil and coolant are getting up to full operating temperature. I understand the coolant flask is no longer in use on newer models? What features are in place to ensure operating temperature continuity?

 

[xBa380]

Going to pick up some pennzoil yellow bottle at WM today after work. Think I'll go with 5w30 to see if it helps any. Will check the plugs too when the oil drains.