10w30 or 5w30 for a quieter engine?

DirtyApe · Jul 28, 2004

My quick question:

1997 Nissan Maxima. Summer temps never get over 95f, Winter lows usually single digits for maybe a weeks worth of days.

manual says 10w-30 for 0f and above, 5w-30 for down to -20f.

So.. either one would work. Using a wix filter on the engine with 79k on it. It isn't overly noisy, but if I can quiet it down a bit, I'd like to.

I'm currently using 5w-30 with no detectable usage between 3000 mile OIC. Would 10-30 make any difference , noise-wise or in any other aspect?

thanks
Marc

DirtyApe · Jul 29, 2004

As far as the noise, it's not the quietest when cold-started and warm running is what most would consider pretty quiet. For the last couple of years I've been using either pennzoil w/ purebase 5-30 or castrol gtx 5-30 exclusively (which ever is lower-priced at the time).

As far as the synthetics, I've never gotten into them, mainly because of price, just to be honest. I was hoping that a move to 10w would be a catchall, being that we have two maximas and a jeep (would be nice to get all them on the same oil).

I'll dump in 10w next time and see how it works out, surely can't hurt

One other question, when you see 5w/30, what does the '5w' mean? (typical newbie question I know...)

csandste · Jul 29, 2004

"UOAs consistently show that conventional 5W-30 motor oils shear down to 20 weight viscosity when warmed after 1,500-2,000 miles."

I agree that they do, but my question is "so what?".

I used to use 10w30 for 9 months out of the year, I'm thinking of switching to 5w30 for nine. I notice a couple of mpg difference with 5w30. Of course summer blends of gas in St. Louis are notorious so that's part of it.

Can anyone tell me what the big deal is with shear down to a 20 if it goes no further?

69 Riv GS · Jul 29, 2004

quote:

One other question, when you see 5w/30, what does the '5w' mean? (typical newbie question I know...)

5w means the low temperature cranking viscosity is lower than 6601 cP at -30*C. It's a standard SAE(J300) grading system.

quote:

UOAs consistently show that conventional 5W-30 motor oils shear down to 20 weight viscosity when warmed after 1,500-2,000 miles.
--------------------------------------------------------------------------------

Let's see some.

It's true, dino 5w-30s do shear.
8 random UOAs I averaged had a viscosity cSt at 100*C of 8.54, that's from a 10.7 starting average.
There's more in the UOA section.

69 Riv GS · Jul 29, 2004

quote:

Can anyone tell me what the big deal is with shear down to a 20 if it goes no further?

When VII molecules are sheared they become unstable. This allows them to change form more easily, ie.sludge.

Hopefully someone more knowledgeable will stroll by to confirm this.

Ray H · Jul 29, 2004

quote:

Originally posted by csandste:
Can anyone tell me what the big deal is with shear down to a 20 if it goes no further?

Since we both drive Hyundais, I presume you're aware that Hyundai is still (at least as of MY 2003) fairly conservative in their recommendation of 5W-20 motor oil (no hotter than 95F. ambient temperature), whereas just about every other manufacturer is either totally on the 5W-30 (with grudging acquiescence to 10W-30) or the 5W-20 bandwagon. Personally, I doubt that 5W-30's gonna hurt a Hyundai motor even in the southwest at this time of year. But, if you're willing to go that route, why not consider one of the better 5W-20s such as Pennzoil, Exxon Superflow, or Motorcraft? These are considered a semi-synthetic what with Group III inclusion and apparently a LOT of moly in the latest batches according to some recent UOAs. Someone posted that the Exxon product is selling for 99 cents/qt. at Advanced Auto Products this month. I believe it was a UOA for a Honda Si.

Ray H · Jul 29, 2004

quote:

Originally posted by garyb80:
Let's see some.

Type in 5W-30 in the subject panel of this site's search engine and limit your search to UOAs. "The Truth Is Out There"

Ray H · Jul 29, 2004

Is the noise related to cold start or warm running? If the latter, obviously it couldn't hurt to try 10W-30 for late spring through early fall. (My own choice of motor oil in my Sonata V6 is either Havoline or Chevron Supreme 10W-30 conventional motor oil depending on availability.) UOAs consistently show that conventional 5W-30 motor oils shear down to 20 weight viscosity when warmed after 1,500-2,000 miles. The other option would be to try 5W-30 M1 since synthetics hold their viscosity better than conventionals. (I say that in spite of the fact that I neither use nor promote the use of synthetic motor oils in "normal" service in engines that don't specify synthetics.)

garyb80 · Jul 29, 2004

quote:

UOAs consistently show that conventional 5W-30 motor oils shear down to 20 weight viscosity when warmed after 1,500-2,000 miles.

Let's see some.

garyb80 · Jul 30, 2004

quote:

UOAs consistently show that conventional 5W-30 motor oils shear down to 20 weight viscosity when warmed after 1,500-2,000 miles.

quote:

It's true, dino 5w-30s do shear.
8 random UOAs I averaged had a viscosity cSt at 100*C of 8.54, that's from a 10.7 starting average.
There's more in the UOA section.

Yes, they do shear. However, not at 1500 to 2000 miles in a passenger car.

Schmoe · Jul 30, 2004

If you got immeadiate ticking sound, lifters/rocker arms, then a thinner oil will quiet it down some or at least not tick as long, when compared with the same parameters to a 10W-30. If it's cold knock, the 5W-30 will also get rid of the knock faster. Bottom line and rule of thinking is that the thinner oils get pumped quicker. When in the case of the Ford modular engines, I really don't think it matters. Oil has to get pumped to the top of the heads, and these are OHC engines, before things will quiet down. In these applications, moly realms supreme. That's why I'm such a staunch supporter of moly oils. I've heard the difference between the non-moly and moly. In my 01 F150 5.4, I switch between 5W-30 and 10W-30 depending on seasons, but there are days when certain temperature over lap, and on those days, the ticking sound is just as loud but not as long.

Ray H · Jul 30, 2004

quote:

Originally posted by garyb80:
Yes, they do shear. However, not at 1500 to 2000 miles in a passenger car.

My mistake, gary - by golly, you're right! The factory-fill 5W-30 only took 542 miles in this 2004 4-Runner's 4L V6... I had slightly worse results at 2,400 miles in my 2.7L Hyundai V6 on ST 5W-30 I'd put in at 600 miles into break-in.

[ July 30, 2004, 04:56 PM: Message edited by: Ray H ]

69 Riv GS · Jul 30, 2004

quote:

Yes, they do shear. However, not at 1500 to 2000 miles in a passenger car.

Are you S-U-R-E about that?
Taking a look at the UOA section might be a good idea.

Drew99GT · Jul 30, 2004

If you've been looking at the UOA results here long enough, you'll see that 5w-30 dino consistently shears to 20 weight, even in as little as 500 miles. 10w-30 is absolutely going to give you added viscosity protection in super high ambient temperatures/high load conditions/A/C on etc. I dunno about you, but have you ever driven the Interstate north out of Phoenix in the summer? Elevation gain of roughly 5,000 feet in ambient temps of 115 degrees F? I'd be scared with 5w-30 dino! I can literally see a difference in oil pressure with 5w-30 oil after it's had 3,000 miles on it compared to good stable 10w-30 dinos like Castrol GTX, which in my opinion after reviewing all the UOA, is the most stable dino.

10w30 or 5w30 for a quieter engine?

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