5w30-10w30 difference?

[onequick99si]

I was in another honda forum and this guy claims to be an oil expert (who wrote this) is this true? I always though running 10w30 in my civic would be better for it (never really gets that cold here in WA)!

At operating temperatures and pressures, there is no difference between 5W30 and 10W30. Hence the "30" rating. You do not get "more protection" from a 10W30 than you would from a 5W30.

5W30 is thinner on cold start. That is a good thing. You want oil to get circulated throughout the engine quickly and the "5W" rating is what you want.

5W30 is what Honda recommends for most of it's engines....unless it's newer and then Honda recommends 5W20. Why would you second guess the Honda engineers? I mean you trust them to design a motor that makes 100bhp per liter but you don't think they know jack-#@$%! about tolerances and lubricants????

10W30's only advantage is that it stays in grade longer. If you are changing every 3000mi then that is not an issue.

 

[Drew99GT]

I'd agree 100% with what he said.

But if you live in a climate that rarely drops to 0 degrees F, you can run 10w-30 no problem.

 

[Ugly3]

Run 5w30!

 

[Patman]

Long time members probably think I sound like a broken record, but I stand firmly by my belief that 10w30 is obsolete. 5w30 can do everything that 10w30 can, and MORE. And there is strong evidence that most conventional 5w30s contain a better base oil than the 10w30 of the same brand.

 

[hominid7]

It's hard to say one-size fits all. If you drive 5 very short trips per day in your car, then 5w30 might be better. If you drive mostly highway miles, and not a lot of cold starts, then 10w30 might be best. Then again, the fuel dilution cause by multiple short trips may survive better with 10w30 rather than 5w30 over the long haul. In addition, oil companies may use slightly better base oil percentage in 5w30 to give it the extra stability it needs than a 10w30. So, perhaps it a coin toss.

Having said that, many oil companies 5w30 and 10w30 are so close to each other that the difference may be not worth worrying over. Take TropArtic/Motorcraft oil for example. At 40*C the two oils are almost the same, rating 64 and 66, at 100*C the two ARE the same. In some oils the 5w30 is actually 'thicker' at operating temp to allow for some thinning over time.

My Mazda allows for 5w30 below 98*F and for 10w30 above -14*F, which pretty much covers the range of temps i'll ever see. I've experimented with both and find little difference. My gut tells me 10w30 may contain just a few less VII's and thus be ever so slightly 'better' in the sense of holding grade and suspending contaminents. My cars seems to idle somewhat smoother with 5w30, but at 80mph it seems somewhat smoother with 10w30, but the difference is almost too small to detect, and my measuring methods are far from scientific!

To confuse the issue, the 'new' Havoline 10w30 is about the same vis as their 'old' 5w30.

'Honda Branded Motor Oil' which appears to be the same as ExxonMobil Superflo, is an oil ive used and like quite a bit. Their 5w30 and 10w30 both have excellent cold and hot weather properties. I've started my Mazda in 15*F weather with 10w30 superflo in the crankcase and it started right up, no lifter noise and no complaints.

There are countless Hondas that have run up 200k-300k using plain old superflo 5w30, so they can't all be wrong. Likewise, there are people out there running everything from 5w20 to 20w50 in their old and new hondas with success. Honda engines are just not that picky

So in conclusion, use either and know your car will likely run 200K-300K without any oil related problems. Due to the fact that you will see very few, if any 100*F + days, and Honda seems to favor thinner vs thicker, 5w30 may be the winner, but if you feel better using 10w30, you wont hurt a thing either. If it were my car, i'd likely choose Superflo 5w30 and a Honda OEM filter and change it every 3000-4000 miles.

Side Note: I owned a 1981 accord in high school. I drove the snot out of it, used pennzoil 10w40 changed it every 5000 miles and when i sold it at 165,000 miles it ran as good and looked as good as the day i bought it. Man i miss that car!

 

[hominid7]

Edit: Assuming the OP's car is a 1999 Honda Civic si, i used the "what oil should i buy" tool on Castrols USA website. It suggested 10w30 for temps over 19*F and 5w30 for all temps. So perhaps a good compromise would be 5w30 in the winter and 10w30 for the summer months.

 

[Drew99GT]

homid, your Mazda manual actually states that 10w-30 is safe to -14F? That's far and away the lowest temp recommendation for a 10w in any owner's manual that I've ever seen.

 

[rpn453]

Quote:

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Long time members probably think I sound like a broken record, but I stand firmly by my belief that 10w30 is obsolete. 5w30 can do everything that 10w30 can, and MORE. And there is strong evidence that most conventional 5w30s contain a better base oil than the 10w30 of the same brand.

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I agree with Patman.
There was a time when less stringent API testing allowed manufacturers to produce 5W-30 grades that were inferior to their 10W-30 grades in terms of engine protection at operating temperatures. This wasn't that long ago - back in the SH and even SJ days - so some still retain the belief that a 10W-30 is better.

 

[m2200b]

I use 10-30 only when Kragen at its sales at $1 or less a qt after rebate don't stock 5-30. I ended up with 10-30 PP this month from Kragen as I never saw 5-30 but couldn't pass up $2 10-30PP. My Mazda and Old 3.1v6 proabably do better on 5-30 and the tercel on the 10-30 but I won't pay 2x to get a nonsale 5-30 for them.

 

[Bryanccfshr]

I agree with Patman. 10w30 is obsolete. I believe that 5w30's are better in every category.

 

[farrarfan1]

There's a UOA posted in the last day or 2 of Havoline 10W30 that sheared well into 20W range in 3,000 miles.There are other examples of 10W20's (not a typo) in the UOA section if a person takes the time to look them up.Patmans right, 10W30 is obsolete, but it will continue to be recomended as a "summer" weight oil by some forever.

 

[KieferS]

10w30=gone.

lets move on

 

[farrarfan1]

Quote:

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10w30=gone.

lets move on

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Never happen.This is one of the questions guaranteed to pop up as regularly as the "Who makes Super Tech"? and "Is 5W20 too thin"? in the oldies but goodies rotation. Among others.

 

[oldmaninsc]

Quote:

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Long time members probably think I sound like a broken record, but I stand firmly by my belief that 10w30 is obsolete. 5w30 can do everything that 10w30 can, and MORE. And there is strong evidence that most conventional 5w30s contain a better base oil than the 10w30 of the same brand.

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One more vote for Patman and his broken record.

 

[KBFXDLI]

5w30..........

 

[Mystic]

I agree with what Patman says. 5W30 (or 5W20 in many vehicles) is the way to go today for cars and trucks. You can use 10W30 in the lawnmower. Of course there are European cars and trucks that require different viscosities.

I did used to be suspicious in the past however when I heard stories about auto manufacturer engineers recommending 5W30 oil in new vehicles but supposedly using 10W30 in their own vehicles. But there is evidence today that 5W30 oils are often superior to 10W30s.

The only thing is somebody is going to have to reach the people at these quick lube places. I have heard numerous stories about 10W30 oil being used at these places (even in the wintertime) because of 10W30 being cheaper to get. With the majority of American cars and trucks now requiring either 5W20 or 5W30 it is time that 5W20 and 5W30 oils are available at the quick lube places. At a G/M I once caught the people there trying to switch 10W40 Mystik concentional oil for the 5W30 Mobil 1 I had brought in. The car required 5W30 oil as the recommended oil (only other oils allowed being 10W30 and 30 WT in warm weather). Not only were they trying to cheat me, they were not even using the proper viscosity for the conventional motor oil. I stood there in their maintenance bay (where customers were not allowed) and watched them put my Mobil 1 in my car. They did not say a word about my not being allowed to be there. They knew they had been caught.

 

[hominid7]

Quote:

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homid, your Mazda manual actually states that 10w-30 is safe to -14F? That's far and away the lowest temp recommendation for a 10w in any owner's manual that I've ever seen.

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Hey Drew,

Actually i've had multiple sources tell me multiple things:

Owners manual
-4*F to 100*F+, 10w30
-20*F to 98*F, 5w30

I emailed Mazda customer service and got this response
They stated above -13*F (-25*C) 10w30 is allowed, and -22*F (-30*C) to 98*F (37*C) 5w30 is allowed.

Castrols "What oil should i buy" tool states to use 10w30 above -13*F and to use 5w30 below 32*F.

My Haynes shop manual calls for 5w30 from -20*F on up to 100*F +, and 10w30 from 0*F on up to 100*F + as well.

It's rare here in North Texas to see anything below 15*F or so, and while it can get hot, usually not hotter than 105*F, so i think for me, given the multiple conflicting information, 5w30 or 10w30 are both safe bets. The dealer uses 5w30 Motorcraft year-round.

 

[Throckmorton]

If 10W-30 is obsolete why does Daimler Chrysler recommend it as the only grade of oil suitable for its 3.5L V6?

 

[Bryanccfshr]

They compliment each other

 

[mitchcoyote]

If 10w-30 is obsolete, then why is it the #1 used weight oil in the United States?