Explain why you up to a 10w in summer.

[Bambam]

I see an influx of "what oil to use" threads,myself included.

After reading thousands of recomendations alot say I use 0wXX or 5wXX in winter and use 10wxx in summer. I believe I understand enough about oil to see no real advantage to this practice in a normal reasonably healthy engine.

For those that practice this ritual,explain. Thanks. Not bashing,just looking to get educated.

 

[bepperb]

A 10w oil will hold it's viscocity longer than a 5w. People are willing to accept this in winter in exchange for easier starting. In summer, starting isn't as much of a problem.

Personally, 5w30 in the summer is fine. I also see no advantage, but I see the logic behind the theory.

 

[Drew99GT]

10w-30s have less viscosity index improver, generally thicker base oils, and generally have slightly higher HT/HS viscosities and lower NOACK volatility numbers. ie. they are more thermally stable.

That's why many people report lower oil consumption in hot climates with a 10w vs. a 5w.

Now, synthetics are another ball game because synthetic base stocks by their nature are more thermally stable then group I or II basestocks, and synthetic 5w30s are fine for hot weather operation. Amsoil ASL, for example, has a lower NOACK then any 10w30 conventional oil.

Many people consider 10w30 to be obsolete, and I'd somewhat agree if we're talking synthetics.

 

[Black_Thunder]

I've seen several topics on here and it seems, well it used to anyways, that 10w30 was more shear stable then a 5w30,

dunno if thats the true anymore, oil has come a long way.

 

[bretfraz]

I don't know if many people are going from a 0W to a 5W or 10W. All 0W oils are going to be full synthetic and their performance is going to be as good, if not better, than a corresponding 5W or 10W synth. I see no tangible benefits from switching if you're committed to synth products.

As for going from a conventional 5W in winter to a conventional 10W, I agree with the comments above regarding 10W benefits.

 

[Jetronic]

price is also a consideration... at least over here the lower W grades are more expensive...

 

[Quest]

Originally Posted By: Bambam
I see an influx of "what oil to use" threads,myself included.

After reading thousands of recomendations alot say I use 0wXX or 5wXX in winter and use 10wxx in summer. I believe I understand enough about oil to see no real advantage to this practice in a normal reasonably healthy engine.

For those that practice this ritual,explain. Thanks. Not bashing,just looking to get educated.


For gasoline engine vehicles, I wouldn't go up to 10 during the summer.

Mind you tho: I don't belong to "mo thicker is betta" crowd to begin with, and none of my Toyotas and Hondas call for anything more than 5W20/5W30.

Q.

 

[Max_Wander]

just look up "temporary shear" and which parts of an engine that it can occur at vs a straight wt oil (one devoid of poly VIIs). 10w30's and other small spread multivis oils act closer to straight vis oils in that they will hold their viscosity better in the high heat, high shear areas of an engine like the top ring area and in the bearing (and turbo if equipped). also VII-laden, wide-spread oils are much more likely to completely break down and oxidize in these high temperature spots and undoubtedly cause varnish and deposits, which is one of the worst slow-kill's to an engine IMO. bear in mind that under your valve cover may look spotless, but your ring pack could be encrusted and gummed with varnish....this is VERY common and can happen on low mileage engines. to put it short, my motto is "just say no to VIIs"

 

[Max_Wander]

as an additional note, this is why so many cars can consume oil even at a young age. once VII's encrust your rings, they can cause sticking on one side and uneven tension, which can cause uneven wear. once the rings begin to wear unevenly, it's game over, your rings will never seal the same again. even if the engine is flushed, a different oil formula is used and the rings free themselves, nothing will change the fact that theyve worn out of round. it's not so much that the rings have worn evenly, all around and have simply worn out their tension, it is almost always the uneven wear caused by sticking from varnish. varnish comes from one main source, VII's.

 

[mechtech2]

I see many say it's OK to use the 10-xx in summer simply because of the temperature. The '10' will flow better at a cold start in summer than a '0'0 or '5' will on a cold winter start.
And this makes sense.

I believe we are covered with a 0 or 5 either way.

 

[TallPaul]

I run almost exclusivelyl 10w30. If I need an oil with better cold start properties, I'll move to a synthetic 10w30 rather than a conventional 5w30. I just like the idea of minimizing the spread and amount of VII. Now I could go extreme and run only straight 30 in summer, and actually have some for that purpose, but mostly will run 10w30 all the time.

 

[JoeFromPA]

I think my question is: is there potential harm in switching from two different oils using different chemistries.

I.e. If I like to run a 10w40 in the summer and a 0w40 or 5w40 in the winter, am I at risk to do more harm than simply using a 5w40 year round?

 

[Mark888]

Originally Posted By: JoeFromPA
I think my question is: is there potential harm in switching from two different oils using different chemistries.

I.e. If I like to run a 10w40 in the summer and a 0w40 or 5w40 in the winter, am I at risk to do more harm than simply using a 5w40 year round?

No chemistry issues. If they can mix synthetic and conventional oil into a synthetic blend, then you can mix two synthetics together without any problem.

 

[addyguy]

I go for the slightly thicker oil, and slightly less consumption 10w30 gives.

 

[Steve S]

Look at a viscosity oil selection chart.

 

[Greaser]

I use a 0W all year.Not worried about VII's breaking down and gumming up my ring packs because the increased detergents in my HDEO will handle that.Plus it's designed to get hammered in a diesel engine so running a HDEO in a gasser is easy street for the oil.

 

[lawdogg]

Originally Posted By: Greaser
I use a 0W all year.Not worried about VII's breaking down and gumming up my ring packs because the increased detergents in my HDEO will handle that.Plus it's designed to get hammered in a diesel engine so running a HDEO in a gasser is easy street for the oil.


As I run HDEOs in both of my vehicles, this is the logic I choose to prescribe to.

I am nervous, though, to start my VR-4 in anything under 30 deg.F with the HDEO 15w40 in it.

 

[Badlees]

You guys running the HDEO's in your gas engines aren't worried about poisoning your CAT's? Just curious because I have run Rotella in my Tacoma but stopped because of the the articles on what it can do to your cat.

 

[FrankN4]

I did a rather extensive study of Mobil 1 5w30 and Mobil 1 10w30.

The 5w30 has a 100C cSt of 11.3, 40C cSt of 64.8, HTHS of 3.09.
The 10w30 has a 100C cSt of 10, 40C cSt of 62, HTHS of 3.14.

Studying UOA's on BITOG, and on other forums, wherever I could find them, I looked at 5000 mile shear. Now, every UOA was not 5000 miles so 4500-5500, lots there.

After 5000 miles the 5w30 would still have an "AVERAGE" 100C cSt of greater than 10, where the 10w30 started. The 10w30 would be in, "ON AVEREAGE" the 9.3-9.5 for the 100C cSt. Most certainly the 10w30 sheared less but the 5w30 still had the best 100C viscosity, best higher temperature protection.

What I do not know is what, if any, the results of the shear are on the base oil. What, if any problems does it cause?

If the HTHS of the 10w30 were something like 3.2, 3.3, that would be a big influence for me. Look at the product data for the 5w30 and the 10w30 you are considering. If the 5w30 has a relevant greater 100C cSt, I would see no reason not to use it year round. If the 10w30 has an equal or greater 100C cSt, I would go with it year round and it might have a better HTHS also.

 

[lawdogg]

Originally Posted By: Badlees
You guys running the HDEO's in your gas engines aren't worried about poisoning your CAT's? Just curious because I have run Rotella in my Tacoma but stopped because of the the articles on what it can do to your cat.


Do you happen to have a link to any of those articles? I ask because it'd be news to me. I'm not worried about the VR-4 as it has no cats, but that's a little alarming for my Jeep. Thanks.