Oil ring/general internal de carbonization and maintenance strategy Toyota 2a-fze. Advice needed, and plan to keep a log

whoopingcrane

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Oct 15, 2011
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My 09’ Camry had consumption from a hardened, leaky valve cover gasket. I put KREEN in each cylinder, let sit for 3~ Hours

Then I put some EDGE 0w40 in with a tough guard filter. I don’t have any more oil leak/consumption. KREEN is a good recommendation, as it DOES work.

Thanks for the recommendation, Ive heard of kreen quite a bit but availability/price was crazy online. Castrol edge full synth 0w-40 was actually on sale for a little over $4 a quart when i bought the mobil for $6/qt, was strongly considering it. Might try it next time if its still at that price.
 
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Thanks for the recommendation, Ive heard of kreen quite a bit but availability/price was crazy online. Castrol edge full synth 0w-40 was actually on sale for a little over $4 a quart when i bought the mobil for $6/qt, was strongly considering it. Might try it next time if its still at that price.
I got it from Kano Labs before they made ya buy it from distributor. The edge I got recently, $21~ cheaper than M1

If you were close I’d ship ya some EDGE 0w40. I still have 3 gallons of ROTELLA 0w40 too
 
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My understanding of the problem with the '07-'09 2AZ-FE engines was that it had to do with an inadequate number/size of oil return holes in the oil control ring land, hence the need to replace the pistons to effectively address the issue. I'm not sure that ring tension was an problematic in those model years. I have a 2AZ-FE engine in my '02 Camry (before the problematic pistons were an issue) that's burning a quart every 1K miles, and has been for the last 80K+miles, but the car is at 308K miles on its OE engine, transmission, etc. I've tried Kreen piston soaks, Valvoline Blue Restore, etc., but there wasn't much effect, if any. Several mechanics' advice for my vintage 2AZ-FE: Add oil, and keep driving. No converter or O2 sensor issues yet. I did find that adding a few ounces of AT205 Re-Seal did reduce/eliminate the blue start-up cloud of oil getting past the valve stem seals, but that had only marginal effect on the overall consumption rate.
 

whoopingcrane

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Joined
Oct 15, 2011
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My understanding of the problem with the '07-'09 2AZ-FE engines was that it had to do with an inadequate number/size of oil return holes in the oil control ring land, hence the need to replace the pistons to effectively address the issue. I'm not sure that ring tension was an problematic in those model years. I have a 2AZ-FE engine in my '02 Camry (before the problematic pistons were an issue) that's burning a quart every 1K miles, and has been for the last 80K+miles, but the car is at 308K miles on its OE engine, transmission, etc. I've tried Kreen piston soaks, Valvoline Blue Restore, etc., but there wasn't much effect, if any. Several mechanics' advice for my vintage 2AZ-FE: Add oil, and keep driving. No converter or O2 sensor issues yet. I did find that adding a few ounces of AT205 Re-Seal did reduce/eliminate the blue start-up cloud of oil getting past the valve stem seals, but that had only marginal effect on the overall consumption rate.
You are correct, and some speculate that the 08+ inclusion of piston oil squirters may also be a reason these seem to be worse than older years. However, I think the low tension oil rings inherently play a part as it appears a fundamental aspect of low tension rings is that they are super thin to reduce surface area and thus friction, which limits the area the oil can pass through and the size of the drain holes. From people who have done the piston swap, they report that the drain hole diameter actually does not appear to be any bigger, but they are positioned and angled differently. Do agree that the only way to truly solve the problem is new piston and rings, im just trying to keep a log and glean any knowledge with this thread, as most threads with this topic seem to be full of one time anecdotes then we never hear how things went going forward.


Speaking of which, I have an update. I checked the oil at 401 miles today. The dipstick read approx. 75% to 80% between the min and max lines, and I slightly overfilled during the change(1mm or less on the stick), so about .3 quarts for 400 miles. That works out to a quart every 1333 miles. Last run I added 2 quarts during a 2.5k miles OCI and it had 3.5quarts(out of 4) when drained, so around 1 quart for 1k miles on the dot. This is way too early in the OCI and too narrow a margin to be conclusive obviously(future oil degradation effects, bad reading etc), but its a decent sign. Ill keep monitoring everytime I fill up on gas. If it holds for the entire 4k OCI I have planned, Ill switch back to valvoline FS HM 0w-20/5w-20 and see if the results are from the 0w-40 M1 oil or the sketchy engine flush. Not a perfect expiriment, but thers anecdotes out there that 0w-40 is the ticket for 2AZ, maybe we can get a better idea.
 
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You are correct, and some speculate that the 08+ inclusion of piston oil squirters may also be a reason these seem to be worse than older years. However, I think the low tension oil rings inherently play a part as it appears a fundamental aspect of low tension rings is that they are super thin to reduce surface area and thus friction, which limits the area the oil can pass through and the size of the drain holes. From people who have done the piston swap, they report that the drain hole diameter actually does not appear to be any bigger, but they are positioned and angled differently. Do agree that the only way to truly solve the problem is new piston and rings, im just trying to keep a log and glean any knowledge with this thread, as most threads with this topic seem to be full of one time anecdotes then we never hear how things went going forward.


Speaking of which, I have an update. I checked the oil at 401 miles today. The dipstick read approx. 75% to 80% between the min and max lines, and I slightly overfilled during the change(1mm or less on the stick), so about .3 quarts for 400 miles. That works out to a quart every 1333 miles. Last run I added 2 quarts during a 2.5k miles OCI and it had 3.5quarts(out of 4) when drained, so around 1 quart for 1k miles on the dot. This is way too early in the OCI and too narrow a margin to be conclusive obviously(future oil degradation effects, bad reading etc), but its a decent sign. Ill keep monitoring everytime I fill up on gas. If it holds for the entire 4k OCI I have planned, Ill switch back to valvoline FS HM 0w-20/5w-20 and see if the results are from the 0w-40 M1 oil or the sketchy engine flush. Not a perfect expiriment, but thers anecdotes out there that 0w-40 is the ticket for 2AZ, maybe we can get a better idea.
Thank you for documenting your efforts and results for this engine. I have a '14 Scion XB with the 2AZ-FE. On the many later dealer communications on this problem, they fully accept that the Scion XB is covered on the enhanced warranty for this problem through the end in 2015. I believe the Camry was the next to last use it though 2010 or 2011 when they changed engine models.

My Scion is at about 63 k mi. I've used 5W20 Castrol Edge or usually Magnatec for some years on 4-5k mi. OCI's. My guesstimated consumption became to be very similar to yours. I was starting to think about doing the Toyota sealed engine qualifying test for meeting their excessive use criteria. I should have about 2.5 years or 37 k mi.'s remaining under the enhancement coverage. For the first time, I used 5W30 Castrol Magnantec on the last change. At first, the oil consumption didn't seem to improve. I'm at about 4.2 k mi. on that change now. I can definitely say that consumption has declined in the past 2k mi. Perhaps a a Qt. per 2k mi. now. I plan on doing a change tomorrow, but will use some 5W20 MT because of Winter approaching and I have it on hand. I'm expecting the consumption to rise again but we shall see. Barring any new developments and perhaps your results on going back to xW20, I plan to try the 0W40 on a change next Spring.

I've also seen it documented that the replacement pistons drain holes are angled differently. I've never seen any definitive info on whether there was a change in the piston rings. Here a link to the dealer service instructions under specifically Scion models. No mention of a change in rings, although it has specific ring install instructions not found in their regular manuals.

https://static.nhtsa.gov/odi/tsbs/2015/SB-10093961-5448.pdf
 

whoopingcrane

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Oct 15, 2011
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46
Quick update.

I have put 1616 miles on it since the OC and today I drained the rest of the leftover 1qt of the jug used for the 4qt OC in and my dipstick read about 3.8 quarts. So result is about 1.2 quarts for 1616 miles, which works out to approx 1 quart of consumption for 1345 miles. This is in line with the consumption rate of my first update, and a ~35% increase in MPQ from the last OCI. The oil is getting quite dirty but not nearly as much as with the Valvoline, which by 1.5k miles was starting to turn black. Maybe the engine is cleaning up a bit or Valvoline HM has alot of cleaning agents in it compared to the M1. The thing I am most interested in is if the piston oil draining issue can be improved by cleaning with simply high quality oil or additives, or the reduction in consumption is due to the different oil/visco used, so I am excited to see what happens when I switch back to Valvoline xW-20 for the next OCI

Thank you for documenting your efforts and results for this engine. I have a '14 Scion XB with the 2AZ-FE. On the many later dealer communications on this problem, they fully accept that the Scion XB is covered on the enhanced warranty for this problem through the end in 2015. I believe the Camry was the next to last use it though 2010 or 2011 when they changed engine models.

My Scion is at about 63 k mi. I've used 5W20 Castrol Edge or usually Magnatec for some years on 4-5k mi. OCI's. My guesstimated consumption became to be very similar to yours. I was starting to think about doing the Toyota sealed engine qualifying test for meeting their excessive use criteria. I should have about 2.5 years or 37 k mi.'s remaining under the enhancement coverage. For the first time, I used 5W30 Castrol Magnantec on the last change. At first, the oil consumption didn't seem to improve. I'm at about 4.2 k mi. on that change now. I can definitely say that consumption has declined in the past 2k mi. Perhaps a a Qt. per 2k mi. now. I plan on doing a change tomorrow, but will use some 5W20 MT because of Winter approaching and I have it on hand. I'm expecting the consumption to rise again but we shall see. Barring any new developments and perhaps your results on going back to xW20, I plan to try the 0W40 on a change next Spring.

I've also seen it documented that the replacement pistons drain holes are angled differently. I've never seen any definitive info on whether there was a change in the piston rings. Here a link to the dealer service instructions under specifically Scion models. No mention of a change in rings, although it has specific ring install instructions not found in their regular manuals.

https://static.nhtsa.gov/odi/tsbs/2015/SB-10093961-5448.pdf

I would do the qualifying test at the last second in 2 years or whenever 35k miles pops up for you just in-case you qualify! I will keep updated on what happens with the switch back to Xw-20, might take a little bit though! In any case it is promising to see that consumption can be reduced even if its just a little without major repair. These engines seem to be very durable as long as you make sure it has enough oil, so any increase in MPQ is good.
 
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I just now stumbled across this thread. The safest path in a situation like this is to add an oil with enough ester concentration to clean yet not too much concentration to worry about effecting elastomers. The ester will clean slowly everything it touches. I don’t know what other companies do but I do know what we do. That is the reason I made our engine cleaner. Once clean using an oil with ester and or alkylated naphthalene will keep the engine clean. Starting with an oil that has ester and or alkylated naphthalene will mitigate the problem.
 
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The Valvoline 0w20 HM is what my Son runs in his 2AZ-FE engine now. Now that is after ~70k of running Penzoil Platinum 5w20 and 0w20 starting out with weekly top ups of PP 5W30 from my stash. Over time (6 years?) oil usage has declined to about 1/4 quart per 5000 mile oil change. Imho it is probably best to run couple treatments of the HPL engine cleaner to speed up the process.
 
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