With pretty much all of the 5W30's UOA end up being a 5W20.....

[Alan]

Gang,

It seems that very few of the 5W30's UOA are a solid 30 at 212 F.Amsoil seems to do well in this regard though.In some cases this stuff is borderline 5W20.Even when sheared down to 5W20 stuff they still show good UOA results.

Could Ford/Honda be on the right track by recommending a more stable smaller viscosity spread in their newer cars by going straight to 5W20.

I think Toyota is semi crazy for recommending dino 5W30 for 7500 miles and would be better off recommeding 5W20 for 4K to 5K OCI being that their recommendation ends up with the customer getting 5W20 anyways.Might as well go straight to the stuff.

I'm also thinking 5W20 would help with internal engine cleanliness also.

What say you?

[ February 12, 2004, 07:20 AM: Message edited by: Alan ]

 

[jorton]

Agreed. There's no use for a 5/30 that has a FP that's lower than 5/20 FP. Base stock quality is the most important feature.
I did read here it's best to keep the factory fill in the motor for 7500 miles on Toyotas. Sounds like a good idea for any make.

 

[berge]

quote:

---

Originally posted by Alan:

I think Toyota is semi crazy for recommending dino 5W30 for 7500 miles .......

---

2004 echo, owners manual
"engine oil and filter should be changed at 5000miles/6months"

 

[TooSlick]

If you forced me at gunpoint to use petroleum oils,

I'd run a 15w-40 commercial engine oil in hot weather and save the 5w-30 for the wintertime ....My experience running 0w-20/5w-20 synthetics in my Tacoma convinced me you have to be careful with using xw-20 instead of xw-30 grades. I'd look at each case individually and then decide if 5w-20 makes sense.

The 30wt Amsoil formulations never come close to shearing down to a 20wt....at worse they will thin out to a midrange 30wt of 10.5-11.0 centistokes.

Tooslick

[ February 15, 2004, 07:46 AM: Message edited by: 59 Vetteman ]

 

[Alan]

Are the Amsoil XXW30 formulated more towards the 40w side?It seems like it when after a long OCI it reads a middle range 30w.

 

[JohnBrowning]

Take a look at Redline 5W30. You would be hard pressed to get this to thin out to a 20Wt. Most of the conventional 5W30 thin badly! This is not an endorsement of 20Wt oils rather it is proof that 5W30's are usualy inferior to their 10W30 counter parts!

Toyota was stupid to recomend 7500 miles with the cheap 5W30's sold here in the America!! They would be better off either adopting a stringent European spec. or deveolping their own.It would have to have tight volitility, flash, TBN and HTHS numbers. This would elimanate the cheaper oils and force a group II/III blend.

A properly blended 10W30 could make it 7500 miles easy even with a conventional oil. THe oil that ships in the Japanesse built models is an excellent conventional oil! It has a robust additive package that is lacking in most OTC oils. THe Honda factory fill is also really robust and looks more like Redline then any other oil from an additive stand point!

If you like to have a large margin for error and you hae a foundness for 5W30 use synthetic!! Amsoil S3K 5W30 and Redline 5W30 are extremely shear resistant!

 

[Alan]

Hi JB,I agree that RL makes an excellent oil but if these newer Toyota's(I own a 99 and 02)do good on sheared down 5W30 wouldn't it make sense to go straight to 5W20 which seems to be way more stable.

The Motorcraft 5W20 seems to be a really good deal being mostly a group 3 for $1.77.

This is another oil I'm thinking of trying in my 02 Sienna.The 2 Toyota UOA's with 0W20's showed really good numbers!

 

[Dr. T]

quote:

---

Originally posted by TooSlick:
My experience running 0w-20/5w-20 synthetics in my Tacoma convinced me you have to be careful with using xw-20 instead of xw-30 grades. I'd look at each case individually and then decide if 5w-20 makes sense.

---

Tooslick, can you comment further on what your experience was?

 

[TC]

I've noticed this theme continually pops up on this site: "Since 'X weight' oil often shears down to 'Y weight' anyway, why not just buy 'Y weight' to begin with since it probably has better ____ and ____ qualities."

Didn't the Detroit (or Tokyo or Munich) auto engineers take all this into account when they published their oil weight spec's in owners' manuals? Did they somehow miss a basic engine lubrication phenomenon, but we figured it out, so dump the manual? Besides, if "X" shears down to "Y," then what does "Y" shear down to?

"The viscosity grade(s) recommended by the vehicle manufacturer depend somewhat on engine design. Engine manufacturers have spent considerable time and expense experimenting with different viscosity grades and have indicated in the owner's manual the grades they feel will best protect the engine at specific temperatures. While one manufacturer's engine may require an SAE 10W-30, another manufacturer's engine may require an SAE 5W-20 viscosity grade. This is likely due to different tolerances within the engine or other engine design factors." http://www.quakerstate.com/pages/carcare/whattoknow.asp

[ February 12, 2004, 10:00 PM: Message edited by: TC ]