5w30 over 5w20

[Gary Allan]

Originally Posted By: BuickGN
Originally Posted By: Gary Allan
It's going to be hard for a high output motorhead from thinking in any other terms than thicker is better. It would be the same with higher output Euro-alloy types.

Just like it's hard for a new construction home buyer not spec'ing a bigger air handler and higher tonnage compressor even though it may produce unfavorable side effects and undue expense.

No one wants to think of 1/2" drywall as being a 1/2 hour fire wall (or whatever it is). They want concrete block.

It's all about margins. People integrate that the bigger the margin ..even if it will never be challenged at the lower/smaller/shorter level ..into "better".

There's no real logic to it. It's like saying you'll live longer if your 3000 miles from a cliff vs 20 feet. This may be true if you're someone who wildly break dances as a routine activity.



I'd recommend that our next safety evolution in automobiles be the installation of titanium roof panels to offer greater protection from stray meteorite hits on the occupants.


It's not just about margins. Look at GM's test using the 3.8L with a low HTHS oil and a higher HTHS oil. Rod and main bearing wear was cut by 5 times with the higher HTHS.



..but suppose that 5X was totally insignificant in shortening the life of the engine from 350k potential miles ..and what were the conditions of the test?

That's the problem with those types of statistical analysis.

We can surely reason that there were millions of 3.8 engines that were ASSAULTED by their owners ..neglected ..abused.. thrashed ..all on low HTHS fluids ..and most survived long enough to be driven to the junkyard.

Now how much fuel was needlessly consumed over that same span just reaching operating visc ..especially when most were operated 20 minutes or less?

 

[Hounds]

Originally Posted By: badtl . . . There is no evidence on this site (which has a vast amount of lubrication information) that suggest[s
5w20 cannot protect as well as a 5w30 in cars for which it was spec'd. . . .

Well, actually there is "some" evidence of that fact.

As has been discussed here, for at least seven years Honda has recommended 5W-20 weight motor oil for most of its k-series engines. And for at least that long there have been documented instances of camshaft galling in the 2.0 liter 160hp Honda Civic & Acura RSX engines (the K20a3 motor) and the 2.3 liter Accord engine. (See, e.g., ephatch.com; Honda-tech.com; vtec.net: search "camshaft galling.") Of course, there's no shortage of speculation concerning potential causes -- lubrication, casting, metallurgy, neglect, high rpm, high mileage, infantile owners -- take your pick. We also know that Honda recommends 5W-30 weight oil for all of its "high performance" (K20a2 & K20Z1) k-series motors (10W-30 for the S2000), and 5W-30 synthetic oil for its turbocharged engines. Of course, short of our getting access to proprietary information from Honda, we can't know for certain why Honda specifies 5W-30 weight oil for the latter engines. But based on what we do know, I'm willing to infer that Honda has determined that virtually any 5W-30 motor oil provides greater protection against oil shearing than (most) 5W-20 weight oils in k-series engines likely to be subjected repeatedly to high temperatures and/or high rpm. Additionally, if anything meaningful can be drawn from the Honda boards, this seems to be the case in K20a3 motors run on 5W-30 weight oils as well.

That enough "evidence" for me.

 

[Gary Allan]

Quote:
I'm willing to infer that Honda has determined that virtually any 5W-30 motor oil provides greater protection against oil shearing than (most) 5W-20 weight oils in k-series engines likely to be subjected repeatedly to high temperatures and/or high rpm.


You mean you're willing to speculate, correct?

Shearing may not be an issue at all. The process variable that this engine encounters (too often for failure occurrences) in the market may make recommending a 5w-30 a wise move.

Do you have any idea on how many "K" engines DIDN'T have issues with 5w-20 oils? I find it really unlikely that Honda didn't research it thoroughly ..much like I don't think that Audi/VW (Saab, you name it) didn't on their alleged sludge issues.

 

[Hounds]

Originally Posted By: Gary Allan
Quote:
I'm willing to infer that Honda has determined that virtually any 5W-30 motor oil provides greater protection against oil shearing than (most) 5W-20 weight oils in k-series engines likely to be subjected repeatedly to high temperatures and/or high rpm.


You mean you're willing to speculate, correct? . . .

No, Mr. Allen, I'm not "willing to speculate."

It's common courtesy to use an ellipsis ( . . . ) when you delete a portion of quoted remarks. You edited my remarks above by deleting the relevant predicate phrase -- "Based upon what we know . . . ." -- in order to reach your conclusion that I was speculating WRT Honda's oil recommendations. You certainly may disagree with my conclusions, but my inference is based on the facts I stated above, not guesswork or speculation, as you inferred.

 

[BuickGN]

Gary, going by your logic that it's all about margins, how do you explain the fact that engines do wear out even if you have a nice big margin? I understand you're probably talking about excessive wear but what if we could reduce the "normal" wear by running a thicker oil? Take a car like mine that spends most of it's life at operating temp. Wouldn't it make sense to worry more about getting as much protection at it's fully warmed up state rather than a few extra minutes with thicker cold oil?

 

[BuickGN]

Originally Posted By: grampi
I thought this has been hashed out a million times in this forum and 5-20 was shown to be at least as good (and better in some cases) than 5-30?


Yes, for your typical short trip Corolla that makes 50hp. Manufacturers are still recommending 40, 50, and 60wts for their performance engines. I'm sure the decision isn't made lightly considering CAFE.

 

[BuickGN]

Originally Posted By: Bryanccfshr
It has, this is purely entertainment now.


Show me where two identical engines have been run on the dyno under the same load for the same time one with a 20wt and one with a 30wt and compared for wear....

I can show you where GM ran two engines with a high and a low HTHS and showed signifigantly less wear with the higher HTHS. Again, I thought that would be the end of it, proof in front of your eyes but again, not good enough for the 20wt speculators.

We've all seen the thread where you had a Ford engine engineer saying he would never run a 20wt in an engine he helped to design. He mentioned wear results based on dyno runs. I don't know how much more you could want. When I saw that, I thought the debate would be over but never fear, the 20wt people always have a new spin to put on things.

 

[toyotaguy]

Well, I believe it. I would not hesitate to run a 30wt or a 0w40 synthetic in my toyota. I have used a heavy 30 and did not lose any mpg

 

[OVERKILL]

Originally Posted By: toyotaguy
Well, I believe it. I would not hesitate to run a 30wt or a 0w40 synthetic in my toyota. I have used a heavy 30 and did not lose any mpg


I'm running 5w40 in my 5w20 spec'd Ford. [censored], everybody thought it was going to blow up when I made a thread about it! LOL!

 

[ekpolk]

Originally Posted By: toyotaguy
Well, I believe it. I would not hesitate to run a 30wt or a 0w40 synthetic in my toyota. I have used a heavy 30 and did not lose any mpg


Well, I'm running a fill of 12 cSt GC in my Hybrid Camry, which specs 0w-20. Compared to the previous fill of PP 0w-20, I am taking a very noticeable mpg hit. On the PP, the car rarely dipped below 35 mpg, per the computer. On the GC, I'm lucky if I can get close to 35. I refilled today at the half-tank mark (always Shell 87), and I was showing 31.8 for that tank.

I'm 1700 miles from changing out the GC. I'll put more PP 0w-20 back in. I might even UOA both fills.

I still want to know where the mass failures are. Ford and Honda went 20 wt back in 2001. The 2010 models are now hitting the street. If this stuff was the liquid evil so many want to believe it is, we'd have been hearing about it, loudly, by now.

 

[Steve S]

On my 2006 Toyota 4 cyl 4x4 X cab manual trans I do notice any difference in the mile per gallon using the Scanguage or the miles and gallon per fillup method. Even the average doesn't change. Ford claims a tenth or two tenths mpgs max improvement. I wonder if the ability for engines to work with 20w oils is that the comp control knock sensors help control pinging loads on the bearings ?

 

[toyotaguy]

not to change the topic. But have you guys ever bought the Mobil 1 5w40 turbo diesel truck oil. Man, that stuff on the finger really clings to it. hard to wash off. I bet that has great film strength.

 

[toyotaguy]

you can keep good mpg by driving the speed limit or 5 over it. This contributes to good fuel economy more so then a 20 wt oil

 

[toyotaguy]

btw that camry is rated for 33 mpg hwy. So I would say on the Gc you are still getting good mpg

 

[Smokescreen]

It would take 5 or more tanks to get a real reading of how your mpgs are doing. Your mpgs could've gone down for that tank because of many reasons.

 

[Gary Allan]

Quote:
(..."Based upon what we know . . . ." -)


What's this "we" stuff, paleface?

Now what you do know is that they spec 5w-30 for those engines. I don't see anything inferred, implied, or specified in the recommendation as to "why".


It could be fuel dilution reduces the viscosity too far. It could be the heat makes it too thin ..etc..etc.

..but.. Pardon my total lack of socialized posting etiquette. I am but a simple man trying to make my way through the universe.

 

[Gary Allan]

Originally Posted By: BuickGN
Gary, going by your logic that it's all about margins, how do you explain the fact that engines do wear out even if you have a nice big margin?


If it's flogged, sure. Marine engines (and this is something I was always puzzled about until I inquired a bit) have only so many hours before they're due for a refit. They're also at WOT most of the time.
Quote:
I understand you're probably talking about excessive wear but what if we could reduce the "normal" wear by running a thicker oil?
I don't think so, unless they're flogged. Remember the Castrol play on words, 90% of all wear occurs at start up.
Quote:
Take a car like mine that spends most of it's life at operating temp. Wouldn't it make sense to worry more about getting as much protection at it's fully warmed up state rather than a few extra minutes with thicker cold oil?


Perhaps. It assumes that your full operating temp requires heavier oil to reduce normal wear. It may. You may have higher spring rates ..and all kinds of other things that the majority of other engines may not have. Like I said, I'm not going to recommend 0w-20 in an Audi A4 TT nor a Cummins.

..I do not, however, think anyone will get a longer life out of a Honda by using 20w-50 ..or 5w-40 ..or even 5w-30. That assumes that they drive it like most people do a Honda ..and not WOT across the Bonneville salt flats for fun.

I will probably experience a certain level of accelerated wear on my 2.5 pushrod engine with using 0w-10. I still do not think that I'm shortening the life span of the engine by any sensible level that is not routinely exceeded by simple neglect by tens of thousands of other 2.5 owners without a passing thought. Their engines will last a long and uneventful life.

 

[OVERKILL]

Originally Posted By: toyotaguy
not to change the topic. But have you guys ever bought the Mobil 1 5w40 turbo diesel truck oil. Man, that stuff on the finger really clings to it. hard to wash off. I bet that has great film strength.


That's what I'm running in my Expedition.

 

[unDummy]

When 5w20 came out, because of Ford's requirement(hint double sequence), it was superior to most 5w30's.
Now that GF4 is common, I wouldn't use the word 'superior' anymore.

So, if you want to use a 5w30, make sure it has ILSAC GF-4 on the label, or make sure its minimally a synth blend.

I've used 0w40 in place of 5w20 and it did quiet the engine down some.

Many 5w30's will shear into a 20wt. Just look at the UOA section.

I also noticed various vehicles in the poster's signature. If 5w30 prevents you from stocking multiple oil weights in the garage, then that too would weigh on the decision.

 

[Steve S]

Originally Posted By: OVERK1LL
Originally Posted By: toyotaguy
not to change the topic. But have you guys ever bought the Mobil 1 5w40 turbo diesel truck oil. Man, that stuff on the finger really clings to it. hard to wash off. I bet that has great film strength.


That's what I'm running in my Expedition.
Gasp!!!