Repairing Bad Oil Consuption 2 AZ-FE Engines

[KAA]

Hi All, this is another video from our main man The Car Care Nut, repairing oil consuption in the 2AZ-FE engine, as always he is full of information and details.

Enjoy

KAA

 

[campbeam]

There are plenty of YouTube videos mainly from the USA about the Toyota oil consumption issue. Some of these videos have supposed "fixes" not requiring an engine rebuild. However as pointed out in The Car Nut's video, it is the upgraded version of the 2AZ-FE with the low tension piston rings which is the main "problem child". 

I do not know if Toyota Australia applied the Toyota Service Bulletin T-SB-0094-11 which appears to be for USA market.

http://australiancar.reviews/2AZ-FE-engine.php

A quick fix with a chemical additive to free the oil control ring is not a real solution for a design issue. Interesting points about the upgraded oil jets and using 5W-30 oil viscosity plus a reduced oil change interval of 6mths or 5000 miles [8000 kms]. Best option would appear to be to avoid a vehicle with an oil burning issue.

[Tony Prodigy]

I suspect, that despite the design issue of the low tension piston ring, owners have inadvertently relied on the stupid log book service interval which is far too late to be doing an oil change in the beginning, and this in fact was setting up this engine for premature failure. I would wonder though, that despite that very design issue, if the oil was changed regularly at a much lower interval, like 5k or so, could the prevention of sludge and varnish still still have the engine burn oil ?

I wonder if owners of that engine have reported oil burning issues even with a meticulous oil change regime of 5k or thereabouts..

That job the CCN did on that Corolla was a mammoth undertaking and totally avoidable, but good on Toyota for acknowledging the problem. My theory is that they always try to appease their biggest market, which is the U.S. of course, and so I highly doubt we got this TSB here. We're small fish compared to America.

If we need something done, we have to fight it out with our dealer networks and waste valuable time in QCAT and NCAT etc and hope it goes our way.

[campbeam]

1 hour ago, Tony Prodigy said:

I suspect, that despite the design issue of the low tension piston ring, owners have inadvertently relied on the stupid log book service interval which is far too late to be doing an oil change in the beginning, and this in fact was setting up this engine for premature failure. I would wonder though, that despite that very design issue, if the oil was changed regularly at a much lower interval, like 5k or so, could the prevention of sludge and varnish still still have the engine burn oil ?

I wonder if owners of that engine have reported oil burning issues even with a meticulous oil change regime of 5k or thereabouts..

That job the CCN did on that Corolla was a mammoth undertaking and totally avoidable, but good on Toyota for acknowledging the problem. My theory is that they always try to appease their biggest market, which is the U.S. of course, and so I highly doubt we got this TSB here. We're small fish compared to America.

If we need something done, we have to fight it out with our dealer networks and waste valuable time in QCAT and NCAT etc and hope it goes our way.

I have had the same thoughts. If you are going to be a long term owner, then 6 month or 5K oil change interval to avoid costly engine repairs.

However, I understand that the oil burning issue for this engine was commonly reported and the USA dealers gave a placating answer that it was "normal" for that engine. Eventually, it was not until oil consumption tests were undertaken and repairs only done on those vehicles burning >1 US quart for 1000 miles.

Taking into account what The Car Nut said in his video with the background from previously viewed similar TouTube videos, it is a combination of the low tension piston rings and lower oil viscosity to improve fuel economy that are the underlying causes for this oil consumption issue. More low viscosity oil getting past the piston rings and eventually clogging up the oil control rings. Also the design of the oil control rings was changed in the engine repair kit.

I particularly noted that The Car Nut specifically stated that the 2AZ-FE engine was designed to use 5W-30 oil viscosity. In hindsight, the upgraded version of this engine was a "quick fix" instead of a costly redesign. Guess that Toyota took those lessons learnt and applied them to the latter 2.5 engine along with improved manufacturing processes that became available at that time.

Something that I have to repeatedly remind myself is to more closely look at the specific vehicle in a YouTube video rather than accept/assume an implied assumption that the problem relates to all models or versions of an engine.

[Tony Prodigy]

I have to agree with that. Just thinking about this process again,
The low tension ring allowing the thin oil to pass through it, with the addition of it being constantly superheated around the oil control rings begins the festering process of sludge build up irrespective of how many oil changes are done hence gumming up and eventually seizing the oil rings.

I'm staggered how the so called engineers failed to see through the concept and consequence of using such a low tension ring. There are other ways to improve fuel efficiency without sacrificing engine reliability and creating liability too. Sheesh.