Using GF-7A instead of GF-7B...

[phantomxj]

Greetings, everyone.

I came here asking a question because I emailed a number of other sources but got no answer back.

I am from Iraq and I own a Chinese-spec Toyota Corolla Hybrid with 8ZR engine. This engine is basically the same as the 2ZR engine. In the summer here, it can get really hot, reaching 50°C (122°F), and I drive about 4,000km (about 2,500mi) every month, which includes a lot of uphill driving.

I am currently using 0w-16 oil but I want to switch to 0w-20. In the manual, it does mwntion that I can use a thicker oil for more protection for these extreme driving conditions... but I noticed that all viscosities higher than 0w-16 are GF-7A while the original viscosity recommended to me is GF-7B. I am curious because I read that this B classification was made for engine with very tight clearances and this got me concerned. Will a GF-7A oil liks 0w-20 cause long-term damage?

 

[ZeeOSix]

…but I noticed that all viscosities higher than 0w-16 are GF-7A while the original viscosity recommended to me is GF-7B. I am curious because I read that this B classification was made for engine with very tight clearances and this got me concerned. Will a GF-7A oil liks 0w-20 cause long-term damage?

The GF-7B is the ILSAC designation for cars that recommend or specify 0W-16 or lower. The GF-7A is the desigation for xW-20 and above. They made the distinction difference because they don't want people putting the thinner 0W-16 or 0W-8 in cars not designed to use oil that thin. Has nothing to do with bearing clearances. Even cars that specify thicker oil have pretty tight bearing clearances. If the manual says you can use thicker oil like a xW-20 then go for it and ignore the GF-7A because that's what it will be for oil that's xW-20 or above.

 

[Japanese]

I am currently using 0w-16 oil but I want to switch to 0w-20.

Yes, you are fine. Go for it!

 

[phantomxj]

The GF-7B is the ILSAC designation for cars that recommend or specify 0W-16 or lower. The GF-7A is the desigation for xW-20 and above. They made the distinction difference because they don't want people putting the thinner 0W-16 or 0W-8 in cars not designed to use oil that thin. Has nothing to do with bearing clearances. Even cars that specify thicker oil have pretty tight bearing clearances. If the manual says you can use thicker oil like a xW-20 then go for it and ignore the GF-7A because that's what it will be for oil that's xW-20 or above.

Thank you for the answer. I thought the ILSAC designation was because of the tight clearances and that thicker oils could cause the engine to clog up or something. That was what I was told. I'll start using 0W-20 from now on.

 

[phantomxj]

Yes, you are fine. Go for it!

Will do! Thanks for the answer.

 

[ZeeOSix]

Thank you for the answer. I thought the ILSAC designation was because of the tight clearances and that thicker oils could cause the engine to clog up or something. That was what I was told. I'll start using 0W-20 from now on.

Engines don't "clog up" from thicker oil. Whoever told you that doesn't understand oil and how engine lubrication works. The only thing that would be remotely close to that is if someone used the wrong W rating for the cold start-up temperature, like using 20W-50 when they tried to start the engine at -30F. Using too thick of a W rated oil in cold temperatures is more critical than the viscosity when the oil is hot. Also, running too thin of hot oil isn't good and can cause more wear. That's why ILSAC GF-7B is only supposed to be used in engines designed for oil 0W-16 and thinner.

Going to 0W-20 is no problem in your case and will give some added wear protection. You could run a 0W-30 or 5W-30 too with no issues since you're in a hot climate.

 

[phantomxj]

Engines don't "clog up" from thicker oil. Whoever told you that doesn't understand oil and how engine lubrication works. The only thing that would be remotely close to that is if someone used the wrong W rating for the cold start-up temperature, like using 20W-50 when they tried to start the engine at -30F. Using too thick of a W rated oil in cold temperatures is more critical than the viscosity when the oil is hot. Also, running too thin of hot oil isn't good and can cause more wear. That's why ILSAC GF-7B is only supposed to be used in engines designed for oil 0W-16 and thinner.

Going to 0W-20 is no problem in your case and will give some added wear protection. You could run a 0W-30 or 5W-30 too with no issues since you're in a hot climate.

ZeeOSix, you are a hero. Thank you very much, you cleared up everything for me. I salute you, sir!

 

[kschachn]

Thank you for the answer. I thought the ILSAC designation was because of the tight clearances and that thicker oils could cause the engine to clog up or something. That was what I was told. I'll start using 0W-20 from now on.

That's a common misconception fueled by Internet chatter and certain media influencers.

Include in the misunderstanding that the ECU is programmed for a grade, or that the electronic oil pump will shear off the drive gear.

 

[Urshurak776]

Where is the "We're Doomed" guy?

 

[Hermann]

That's a common misconception fueled by Internet chatter and certain media influencers.

Would "The Thickies" on this site be considered "certain media influencers"

 

[ATex7239]

Go for the -20 and don’t worry about it.

A 0w-16 at startup during the frigid North American/Canadian winter is going to be 10x thicker than anything you’ll be dealing with in the Middle East. If engines were that sensitive to viscosity change, we’d all be dealing with seasonal engine failures.

Modern multigrade oils have removed any concern with oil thickness harming an engine.

 

[CleanSump]

Where is the "We're Doomed" guy?

I hope the stealth-shield is hiding this thread from them. It's an honest question and he's safe using xW-20 or xW-30.

 

[fantastic]

Yes, you can go to 7A. The 7B was for lower viscosity introduction & got their own spec.

 

[Vexorg]

Thank you for the answer. I thought the ILSAC designation was because of the tight clearances and that thicker oils could cause the engine to clog up or something. That was what I was told. I'll start using 0W-20 from now on.

The physical size of the actual hydrocarbon molecules is extremely small so it would be like comparing a golf ball (molecule) to the height of mount Everest (clearance). As was posted elsewhere, using the wrong (20w50) at -30 is more of a concern.

 

[phantomxj]

That's a common misconception fueled by Internet chatter and certain media influencers.

Include in the misunderstanding that the ECU is programmed for a grade, or that the electronic oil pump will shear off the drive gear.

Yeah I have heard it a number of times, so I went to the support team of one of the big names in the lubricants fields and some others but got no answers back.

Thanks for the clarifications, appreciate it.

 

[phantomxj]

Where is the "We're Doomed" guy?

Who is this guy?

 

[phantomxj]

I hope the stealth-shield is hiding this thread from them. It's an honest question and he's safe using xW-20 or xW-30.

Let's hope the shield is working... or else, we're doomed.

 

[CleanSump]

Let's hope the shield is working... or else, we're doomed.

He has multiple names. I keep putting him on ignore, but always pops up with new names.

 

[phantomxj]

He has multiple names. I keep putting him on ignore, but always pops up with new names.

He is determined.

 

[Japanese]

Will do! Thanks for the answer.

If I live in the Middle East with ambient temps of 50°C (122°F) I would definitely run 0W-30 or 5W-30 oil.
What is the lowest temp in your region?