Toyota 4.0 v6 0w20 oil? Wtf?

Boatbuilder79

Active member
Wife’s car has the 4.0 v6. From what I understand this is the same engine that has been around since 2005. My 2005 tundra had the 4.0 and called for 5w30 but liked 10w30 better.

When I looked at the oil cap on my wife’s car it says 0w20?

0w20? That’s like water. Wtf?

Is this some crap to meet cafe standards? Is there any difference in the engines or just the oil cap?

Also,

I do realize that I am questioning the Toyota engineers and this might offend some so flame away if you must,
 

(none)

Adventurer
Who cares what oil they recommend? Do you think the motor has all the same bearings in it with same tolerances since 2005? Do you think toyota just randomly started throwing 0w20 oil caps on motors without testing it? Are motors running the 0w20 oil failing left and right??

Doubt it. Run whatever you want. I ran 0w20 in my 4.0 without any issues.
 

tacollie

Explorer
If 30 is better than 20 then maybe you should try 40! I believe in 06 they started specing some of the 4.0s with 20. I think either is fine for that motor. It's pretty tame. I ran both and had zero issues in my Tacomas.

I believe the 1grfe was released in 02 for the 03 4Runners.
 

lugueto

Adventurer
Bear in mind, your wife's car has the second generation of the 1GR-FE.

Most of the improvements I dont really understand, honestly, but I'm sure the change in oil viscosity is because of these changes.
 

DaveInDenver

Expedition Leader
Toyota retroactively changed some oil specifications to allow either 5W20 or 0W20, the 1GR-FE included. That was TS-EG018-06, which I attached. They continued to specify 5W30 in the book and oil cap for 1GR Tacomas (at least in 2008, when mine was made) even concurrent with suggesting 0W20 was acceptable. So apparently the use of 0W20 or 5W20 has nothing to do with tolerance changes and there's a definite MPG gain using 0W20, so my belief is the move to 0W20 is CAFE-driven.

Our Forester came with a 0W20 recommendation. Our was made in Japan and Foresters with turbos sold here or any sold overseas with the same FB25 engine presumably from the same engine plant in Japan are specified with 5W30. It's only naturally aspirated U.S. Foresters that were supposed to use 0W20. The owner's manual even says it's a recommendation, not requirement, and that 5W30 is acceptable if necessary and can be left until the next oil change. So if it was a journal or ring clearance problem the damage would be done in 5,000 miles, so it can't be that.

I run 5W30 in both my truck and her Forester. In the Forester the mileage is about 2 to 3 MPG lower but the oil consumption is greatly reduced, which is a real concern with the FB Subarus. To my ears I think the engine is less noisy but it's not a quiet engine so that's purely subjective. I've never tried 0W20 in my truck.
 

Attachments

DaveInDenver

Expedition Leader
Here's a more recent chart of oil viscosities for Toyotas. It's slightly different than the TSB, although there's still some years that overlap all 3 viscosities.

This also assumes you're using Toyota oil, which is probably not synthetic for 5W20/5W30. It's only possible to make 0W oil in synthetic.

526826
 

shade

Well-known member
Here's a more recent chart of oil viscosities for Toyotas. It's slightly different than the TSB, although there's still some years that overlap all 3 viscosities.

This also assumes you're using Toyota oil, which is probably not synthetic for 5W20/5W30. It's only possible to make 0W oil in synthetic.

View attachment 526826
Interesting. I've always used 5W-30 synthetic in my 2012 1GR-FE Tacoma. I'll check the BITOG forums before deciding to change to 0W-20. Thanks for the chart.
 

Boatbuilder79

Active member
Tundra? Should've been a 4.7 v8? I don't recall a v6 option in the later 1st gens.

Sent from my Pixel 3 using Tapatalk
It was a 2 wheel drive. You could only get 4x4 if you got the v8. That truck is still in the family as a farm truck. It was a long bed with the 6 speed manual which is an awesome combination. I would still be driving it if I didn’t need room for child seats.
 

DaveInDenver

Expedition Leader
Interesting. I've always used 5W-30 synthetic in my 2012 1GR-FE Tacoma. I'll check the BITOG forums before deciding to change to 0W-20. Thanks for the chart.
Same here, standard issue Mobil1 5W30.

This post has some interesting comparisons. One of which is the 2GR-FKS used in the Lexus RC350, both of which are Japanese-built cars essentially identical save for the driving side. Outside of the U.S. there's the traditional multiple band viscosity vs. temperature chart but the U.S. delivered vehicles only recommend 0W20.

 

Boatbuilder79

Active member
Does anyone have Access to the shop manuals?

We could probably look up the tolarances In them.

I would bet $1.00 that they just swapped the oil spec

0w20 is not gonna kill the motor before the factory warranty runs out. But it might make someone have to go car shopping in 10 years instead of 11 which is to their benefit.
 

SC T100

Adventurer
Huh! So I could run 0W-20 or 5W-20, or 5W-30 (what I run now) (and presumably 0W-30) in my 4.7? I wonder what that would do for MPG. Less viscosity and more flow at operating temps seems like a winner.

But...I'm a bit old-school in running what is spec'd in the manual. I did, however, run 0W-30 in my T100 and there were no issues while I had it.

Who knows...but I am tempted to run 5W-20 to see what it does.
 

shade

Well-known member
Same here, standard issue Mobil1 5W30.

This post has some interesting comparisons. One of which is the 2GR-FKS used in the Lexus RC350, both of which are Japanese-built cars essentially identical save for the driving side. Outside of the U.S. there's the traditional multiple band viscosity vs. temperature chart but the U.S. delivered vehicles only recommend 0W20.

I don't care for what the place has become, but I should probably get over there a little more often. Thanks again.
 

shade

Well-known member
Interesting TW thread.

I have a long, desert towing trip coming up, so I may give 0W-40 a try.
 

luthj

Engineer In Residence
Oil viscosity is most important for the hydrodynamic bearings (crankshaft/camshaft). These rely on the oils shear viscosity. Any breakdown below the minimum will result in bearing contact, and rapid wear. Most folks think in terms of pour viscosity (static), which is not the same as kinematic/dynamic viscosity. Look at the chart below. Note that 20 and 30 weight have nearly the same shear (dynamic) viscosity. Also note this is rated at a higher temperature, because crank bearings impart lots of heat to the oil. Simply put, Toyota determined that the bearing design on these vehicles can acceptably operate on SAE 20 oil. Oil has come a long way in the last 20 years, and most SAE 20 oils have high shear viscosity, but lower static viscosity. This means they pump easier, reduce flow losses, while still providing what the bearings need. A lighter grade oil can improve fuel economy as well. Older vehicles had large clearances in their bearings, which needed thicker oils to avoid high volume requirements. Vehicles have been getting tighter/better MFG tolerances on bearings etc. Oil standards at the SAE have not been static either. Those two letters after the SAE/API cert mean something. It can be worthwhile to compare the specs from when the car was made, to the current ones.
526831

SAE Viscosity GradeHigh Shear Rate Viscosity @ 150 Degrees Celsius (mPa.s)Maximum Viscosity @100 Degrees Celsius (mm 2/s)Minimum Viscosity @ 100 Degrees Celsius (mm 2/s)
603.7<26.121.9
503.7<21.916.3
403.7**<16.312.5 9.3
302.9<12.59.3
202.6<9.35.6
 
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