5w30 in a spec 5w20

[Shannow]

fpracha, I get where you are at, the old "but a 5W30 shears down to a 20 anyway" (you didn't use those words, but they are oft used).

I agree with your sentiment, but as protection is HTHS, and the 30 will start out with about 15% more HTHS.

I'm not sure how HTHS changes with KV (but am always keeping an eye out).

 

[KCJeep]

Many here seem to think the HTHS drops at about half the rate the kinematic viscosity does when the oil shears but I have no idea where that notion comes from.

In my little world, even if I use 5w30 and it shears badly I am still at worst on the high end of a 20 grade in an engine supposedly spec'd for 5w20 anyway.

The 5w20's shear too, countless UOA's on here prove it, and I am just not comfortable running around with an engine oil in the 7's kv100 (extremely common) or even 6's (zikes I've seen it on the GDI's).

 

[Shannow]

True, the "30 becomes a 20" is only a logical argument if the 20s were rock solid shear wise.

 

[sdude2k2000]

Originally Posted By: hatt
Originally Posted By: sdude2k2000
Bottom line - If the manual / oil cap says 5w20, run 5w20. If you want to run 5w30 because the whispers in your ear say to, then run 5w30 instead. If you want to UOA to see which works best, okay.
The manufacturers specing other oils in the rest of the World for the same engine is more than a whisper.


No it's not. It's the oil companies catering to those country's populations who have always run thicker stuff because "that's what we do!".... much like the arguments I hear in here from the "thicker is obviously better!" crowd.

Originally Posted By: BlueOvalFitter
Originally Posted By: sdude2k2000
Bottom line - If the manual / oil cap says 5w20, run 5w20. If you want to run 5w30 because the whispers in your ear say to, then run 5w30 instead. If you want to UOA to see which works best, okay.

What if you know, for a fact, that your engine was manufactured from 1997-2008 and that the internal clearances and tolerances had NEVER changed in all of those years? And, that said engine was originally spec'd 5W30 oil from 1997-2000? Then, in 2001, for CAFE reasons, it was then spec'd 5W20?
Interesting dilemma, huh?
So, no, it's NOT the bottom line!

Ignorant statement based on your personal feelings / opinions of CAFE. Nobody will argue CAFE moved the oil industry forward and towards lighter grades, but that doesn't mean they can't protect every bit as well as a 30-grade in approved applications. Police vehicles, taxis, etc are subjected to the harshest oil conditions imaginable in a PCMO application (heavy stop & go, a lot of idle time, etc)... and their vehicles run just fine and dandy on 20-weights. UOAs and engine tear-downs have proven that time and time again. So until you provide something beyond your opinion on CAFE, what I said really is the bottom line... run whatever makes YOU happy and helps YOU sleep better at night.

 

[BlueOvalFitter]

Originally Posted By: sdude2k2000
Originally Posted By: hatt
Originally Posted By: sdude2k2000
Bottom line - If the manual / oil cap says 5w20, run 5w20. If you want to run 5w30 because the whispers in your ear say to, then run 5w30 instead. If you want to UOA to see which works best, okay.
The manufacturers specing other oils in the rest of the World for the same engine is more than a whisper.


No it's not. It's the oil companies catering to those country's populations who have always run thicker stuff because "that's what we do!".... much like the arguments I hear in here from the "thicker is obviously better!" crowd.

Originally Posted By: BlueOvalFitter
Originally Posted By: sdude2k2000
Bottom line - If the manual / oil cap says 5w20, run 5w20. If you want to run 5w30 because the whispers in your ear say to, then run 5w30 instead. If you want to UOA to see which works best, okay.

What if you know, for a fact, that your engine was manufactured from 1997-2008 and that the internal clearances and tolerances had NEVER changed in all of those years? And, that said engine was originally spec'd 5W30 oil from 1997-2000? Then, in 2001, for CAFE reasons, it was then spec'd 5W20?
Interesting dilemma, huh?
So, no, it's NOT the bottom line!

Ignorant statement based on your personal feelings / opinions of CAFE. Nobody will argue CAFE moved the oil industry forward and towards lighter grades, but that doesn't mean they can't protect every bit as well as a 30-grade in approved applications. Police vehicles, taxis, etc are subjected to the harshest oil conditions imaginable in a PCMO application (heavy stop & go, a lot of idle time, etc)... and their vehicles run just fine and dandy on 20-weights. UOAs and engine tear-downs have proven that time and time again. So until you provide something beyond your opinion on CAFE, what I said really is the bottom line... run whatever makes YOU happy and helps YOU sleep better at night.

I have nothing against CAFE. Look at my signature. Just because "YOU" say it's the bottom line doesn't necessarily mean that. Remember, the same tests that were conducted on 20 weights were also done with 30 weights. I was merely stating that just because "YOU" say to use what the manual reads or the oil cap reads, is not always the case. If it was originally spec'd for a 30 weight there is no reason to not run a 30 weight.
And, yes, I do sleep better at night knowing that "I" can decide which oil to use and not be told what to use.

 

[sdude2k2000]

.........So your argument is that because I say to listen to the manual and/or oil cap, proven time and time again by UOAs and engine tear-downs, that it's NOT the bottom line? Your argument is to instead listen to the folks on here that "know it all"?

Awesome. I'm out.

 

[BlueOvalFitter]

Originally Posted By: sdude2k2000
.........So your argument is that because I say to listen to the manual and/or oil cap, proven time and time again by UOAs and engine tear-downs, that it's NOT the bottom line? Your argument is to instead listen to the folks on here that "know it all"?

Awesome. I'm out.

No, I don't listen to the folks on here. I can decide for myself what oil to use in my engine. As I have stated before, it was originally spec'd a 5W30 and later a 5W20. So, if I choose to use a 5W30, then I will. Just because 5W20 is proven to be a great oil doesn't mean it's just as good or better than a 5W30, in some cases.
Your turn.

 

[Triton_330]

Originally Posted By: BlueOvalFitter
Originally Posted By: sdude2k2000
Bottom line - If the manual / oil cap says 5w20, run 5w20. If you want to run 5w30 because the whispers in your ear say to, then run 5w30 instead. If you want to UOA to see which works best, okay.

What if you know, for a fact, that your engine was manufactured from 1997-2008 and that the internal clearances and tolerances had NEVER changed in all of those years? And, that said engine was originally spec'd 5W30 oil from 1997-2000? Then, in 2001, for CAFE reasons, it was then spec'd 5W20?
Interesting dilemma, huh?
So, no, it's NOT the bottom line!

+ 1

That is the cold hard truth. As an owner of a 2001 F-150, I believe you've hit the nail on the head here, BlueOvalFitter.

Originally Posted By: sdude2k2000
.........So your argument is that because I say to listen to the manual and/or oil cap, proven time and time again by UOAs and engine tear-downs, that it's NOT the bottom line? Your argument is to instead listen to the folks on here that "know it all"?

Awesome. I'm out.

LOL.

Please. You're the one doing what you're accusing Blue of doing, not him.

Ford's specification for the Modular engines (and maybe others, but for sure the 4.6L and 5.4L) back in the late 90s was indeed 5w-30.

Then, in the early 00s, the spec changed to 5w-20.

The engines never changed. It was the same engines that previously were spec'd to use 5w-30.

So for you to say Blue is wrong about using 5w-30 in his Ford that spec'd 5w-30 before it spec'd 5w-20, is quite irrational.

He's not acting like a know-it-all. But you saying "awesome, I'm out" is quite telling of your maturity.

~ Triton

 

[Tony10s]

Originally Posted By: BlueOvalFitter
.... If it was originally spec'd for a 30 weight there is no reason to not run a 30 weight. ....


+1

This is my reasoning as well.