Burning oil at same rate regardless of oil thickness --- What does it tell us?

Could you please check and see what oil viscosity it says on the filler cap of the engine? and let us know.
My 2008 gen2 in the UK says 0w/20 as do all gen3's. OP Grumpy Cabby noted on PC that when the dealer used 5w/30 his fuel consumption rocketed. In the UK/EU handbooks it states that if an oil other than 0w/20 is used it should be changed at 5000 miles "5000 miles early" and refilled with 0w/20.

John (Britprius)

 

Thanks, but I was just trying to establish the recommended grade of oil in Oz for the gen3. It is strange that for gen2's some use oil while others at the same millage do not. However some oil use "we use pints or litres here" say half a litre or more in 5000 miles I would consider quite acceptable. It is not so long ago that this would have been good for a new car. As you know I have only ever used 0w20 "apart possibly from what came in the factory fill" for the last 100,000 miles.

John (Britprius)

 

Here it's 5/30. That's going by the Manual. Nothing on the filler cap except a handle. Much hotter than Pommy land.

 

Yes I do understand that, but what I stated goes for all of Europe including places such as Greece and Turkey where summer temperatures run at 40 to 45 C.

John (Britprius)

 

Hi John,

I've attached a copy of the relevant page from the Oz manual. That's all I can go by.

Another thought! Greece and Turkey get colder in winter than we do in most places.

 

I'd be careful about using some of those really heavy duty diesel oils in an oil burning Prius. The one thing that he does have to lose is the catalytic converter. Some of those oils literally have about 3x the amount of additives which potentially can poison a cat (compared with a standard api sm/sn oil). For example, someone over at bitog posted a virgin oil analysis of "Delo Gold" and it had very high amounts of additives. Can't remember the exact amounts but it was huge, something like 1700 ppm Zn, 800 ppm Mo and 300 ppm Bo.

 

Hi Feri, Thanks for the PDF.
From reading the page from the manual 0w20 is a recommended grade of oil for you in Australia, covering the same temperature range as 5w20 and 5w30.
It does not state preferred viscosity 5w20 or 5w30 although the wording is somewhat different to the European manual where as I previously stated "if a higher viscosity than 0w20 oil is used this must be changed for 0w20 after 5000 miles".

John (Britprius)

 

I guess Toyota would have done their research and have reasons. Our reccommendations go with 10,000km oil changes.

 

They claim the ARX is attracted to the metal like the true synthetic oils (ie group 5 oil) and you need a regular G2 or G3 synthetic to rinse properly

My translation is ARX sticks to and loosens the stuff and you need to rinse it off with plain oil. That is why I don't like to call it a "Clean" cycle - gives the impression that the gunk is removed in one step.

In my case, the "treatment" phase freed the oil ring(s) and reduced the oil consumption - maybe the subsequent rinse cleared it out or flushed it off the engine surfaces and into the filter

 

Hi John. Yes I don't see anywhere in the posted manual page that says 5w30 is the preferred. I think what Feri is saying is just that the Toyota Australia chooses to use 5w30. This may be as much to due ease of availability as anything else.

In any case, the manual definitely makes it clear that 5w30 is no problem for any temperature range that you can experience here.

 

It happens all the time in some Toyota cars (as well as Saturns) . I had that in my RIP corolla.

When that happens, you get accelerated ring/cylinder wear and nothing will help at that time. The time to act is when oil consumption starts.

 

The reason you see improvements is due to removing piston deposits that accumulated during oil burning.
Since you had no oil consumption improvement after the initial cleaning, it's probably irreversible. When I had my corolla, engine flush/piston soaks would work for 3,000-5,000 miles (depending on oil type) and then consumption would come back. Clearly the piston oil holes were plugged up, but there was no severe damage to rings yet. Now, that was at the 70,000-90,000 miles mark.

 

Maybe this can help (snippet from another thread):
" If a PCV valve gets gummed up, you will burn some oil. It is a genarally good protocol in most cars to replaced the PCV at regular intervalls..."