Can I put 0w20 in 2AZ-FSE (Toyota 2.4L 4cyl 2005 Scion tc) normally runs 5w30

Owen Lucas

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Let's not make things overly complicated. The resulting viscosity when mixing two oils
is linear enough and the result will be very very close to a simple calculation. Scientific
articles are saying this, VOAs with mixed oils are saying the same. I am aware there has
been some dispute about this a several times, but IMHO it isn't worth the effort. Even
if it was somewhat unpredictable, does it actually matter if the resulting mix is 11.4 cSt
or 11.6 cSt at 100°C? And how do you ever know? How precise is a Blackstone analysis?
No reason to lose any sleep over it. Mixing this 0W-20 with a stout 5W-40 will definitely
result in something thicker than mixing it with a 5W-30.

But again, I'd just use straight 5W-30 or a proper 0W-40 anyway.
Very interesting, thank you for your insight on this.
 

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Ok I see what you mean, so there aren't oil molecules / chains that are 4 weight or 28 weight present. But is it fair enough to say this mathematically as an average and would it behave as if it were a 4w28?
No, because all the grades are ranges in the first place. Take a look at SAE J300:
sae-j300-motor-oil-viscosities.jpg
 
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@Owen Lucas - you got several easy options:
  • stick with synthetic 5W-30
  • go with High Mileage 5W-30 (not my favorite as each manufacturer has his own definition of what constitutes high mileage)
  • go with a 0W-40 which is essentially a thicker 0/5W-30 due to how modern 0W-40 oils are formulated
  • or you can always try to defy the odds and go with 0W-20 - and if you choose this route, then please post at least one or two UOAs so we can all see if the drop in viscosity has any measurable impact on your engine
If you choose to go with 0W-20, nothing spectacular will happen. Most likely oil consumption will increase, as well as your wear rate. But your engine won't go bad overnight, it will struggle for a long time on that thin oil before it gives up the gost, if ever. The difference between fuel economy ILSAC oil viscosities is pretty small, I would say borderline insignificant, to the point that 5W-20 has become irrelevant and 5W-30 only exists to provide an alternative oil with better NOACK and flash point for certain turbo charged engines. Even those are slowly moving to 0W-20, just look at the Toyota Supra.
 

Owen Lucas

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@Owen Lucas - you got several easy options:
  • stick with synthetic 5W-30
  • go with High Mileage 5W-30 (not my favorite as each manufacturer has his own definition of what constitutes high mileage)
  • go with a 0W-40 which is essentially a thicker 0/5W-30 due to how modern 0W-40 oils are formulated
  • or you can always try to defy the odds and go with 0W-20 - and if you choose this route, then please post at least one or two UOAs so we can all see if the drop in viscosity has any measurable impact on your engine
If you choose to go with 0W-20, nothing spectacular will happen. Most likely oil consumption will increase, as well as your wear rate. But your engine won't go bad overnight, it will struggle for a long time on that thin oil before it gives up the gost, if ever. The difference between fuel economy ILSAC oil viscosities is pretty small, I would say borderline insignificant, to the point that 5W-20 has become irrelevant and 5W-30 only exists to provide an alternative oil with better NOACK and flash point for certain turbo charged engines. Even those are slowly moving to 0W-20, just look at the Toyota Supra.
I have a Blackstone kit here so I will make sure to take that UOA if I go 0w20, but the 0w40 is starting to sound pretty enticing and I don't want to harm this engine. I think I can get another 50k easy out of the 2AZ-FE. I don't recall seeing the 0w40 on the shelf but I'll take a look next time I go.
 
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Here's the Toyota TGMO application chart. It doesn't list the '05 Scion TC. But the 2AZ-FE was used in the 2002+ Camry (and other models), and it lists 5w30, 5w20, and 0w20 as acceptable.

74818_Toyota_Motor_Oils.jpg
 
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I have a Blackstone kit here so I will make sure to take that UOA if I go 0w20, but the 0w40 is starting to sound pretty enticing and I don't want to harm this engine. I think I can get another 50k easy out of the 2AZ-FE. I don't recall seeing the 0w40 on the shelf but I'll take a look next time I go.
What are you looking for in the UOA to tell you if the oil was acceptable in the engine? Spectrographic analysis doesn’t tell you that.
 
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New guy here, long time lurker 1st time poster. I hope I am in the correct thread.

I have a lot of 0w20 (full synthetic) from previous projects and am thinking of using it as my winter oil. My 05 Scion tc has 180K miles and I use it mostly on the highway. Had the oil changed by the dealer with regular dino or whatever they put in it for the first 100k and have been using mobile 1 high mileage synthetic ever since. It burns about half a quart every 5K miles, maybe less. For this reason I just fill the engine with 5 quarts instead of the usual 4 and everything works out fine.

Is 0w20 too thin for this engine? I live in the midwest and we have cold conditions starting very soon with maybe 2 months of near freezing temps.

Thank you everyone and happy Labor Day.
If you don't have hot clatter, possibly you could thin it a bit out using a 1/2 quart of 0W20. I wouldn't go further than that.
Use same brand and formulation if possible.
Here is a Toyota TSB, read the last note of page 2
 

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ZeeOSix

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Ok I see what you mean, so there aren't oil molecules / chains that are 4 weight or 28 weight present. But is it fair enough to say this mathematically as an average and would it behave as if it were a 4w28?
The "weight", which is a term used to describe the "viscosiy rating" (per SAE J300 shown in post #42) is not based on the physical weight of the oil, but rather the way the oil physically flows at a certain temperature.
 

Owen Lucas

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If you don't have hot clatter, possibly you could thin it a bit out using a 1/2 quart of 0W20. I wouldn't go further than that.
Use same brand and formulation if possible.
Here is a Toyota TSB, read the last note of page 2
Thank you for the TSB, looks like I missed the deadline by a year since my Scion is an 05 but actually built mid 2004. Makes me wonder what mechanical differences there could be between and 05 and 06 engine to allow 0w20 usage in the newer engine.
 

Owen Lucas

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What are you looking for in the UOA to tell you if the oil was acceptable in the engine? Spectrographic analysis doesn’t tell you that.
For increased wear metals, but I don't think I'm going to go the 0w20 route though. Looks like the 2AZ-FE was approved for 0w20 the following year after mine was built, are there mechanical differences between an 05 and 06 engine? I have no idea but I guess it doesn't matter.
 
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New guy here, long time lurker 1st time poster. I hope I am in the correct thread.

I have a lot of 0w20 (full synthetic) from previous projects and am thinking of using it as my winter oil. My 05 Scion tc has 180K miles and I use it mostly on the highway. Had the oil changed by the dealer with regular dino or whatever they put in it for the first 100k and have been using mobile 1 high mileage synthetic ever since. It burns about half a quart every 5K miles, maybe less. For this reason I just fill the engine with 5 quarts instead of the usual 4 and everything works out fine.

Is 0w20 too thin for this engine? I live in the midwest and we have cold conditions starting very soon with maybe 2 months of near freezing temps.

Thank you everyone and happy Labor Day.
Maybe a BIT late to the party, but agree that using the 20 grade oil by itself is not a good idea. But mixing it with a thicker oil would keep it in the viscosity range you want. Find some 0w-40 or 5w-40 and you should be good to mix 50/50.

Here is a thread I started about mixing; the 5w-20 mixed with 20w-50 came out to a thinnish
40 or thick 30.

 
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If you don't have hot clatter, possibly you could thin it a bit out using a 1/2 quart of 0W20. I wouldn't go further than that.
Use same brand and formulation if possible.
Here is a Toyota TSB, read the last note of page 2
NOTE:
DO NOT use these oils in engines other than those listed above. These low–viscosity oils cannot maintain lubrication effectiveness in engines with older designs and could result in smoke emissions from the tailpipe and/or unusual engine noise.
 
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There were changes to the engine around 2006, though I can not say if it was used in all models. This engine increased compression, used a different intake cam, and added piston oil squirters.
 
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