Explain why you up to a 10w in summer.

[SnakeOil]

Sometimes 5w30's have better base stocks than the 10w30's. I say you are throwing the dice.

But then again, most of the ghetto rigged Chrysler V6 engines ask for 10w30 because of all the hot spots in the engine. My buddies replace one or two a week at a super high volume C.J.D. Dealer because of low oil pressure from sludge.

 

[Doug Hillary]

Hi,
Bambam - You said this;
"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."

This is why multigrade lubricants were introduced around 60 years ago. I am still amazed that people change multigrade lubricants seasonally where the Manufacturer prescribes them for year round use

 

[Drew99GT]

Originally Posted By: Doug Hillary
I am still amazed that people change multigrade lubricants seasonally where the Manufacturer prescribes them for year round use



Maybe because many owner's manuals state to via viscosity charts?

The NOACK for conventional 10w-30s is usually around 11; it's usually around 14 for 5w-30.

Bottom line, when dealing with conventional oils, 10w is more thermally stable then 5w.

 

[RTexasF]

I do not change, it's absolutely pointless.

 

[caprice_2nv]

I just bought an 89 Caprice with 304k miles on the original 305. The previous owner (i believe the 2nd owner) has been getting the oil changed at the dealership with regular 5w30 as long as she's had the car and it still does not use any oil. I also just took my very beat up ghetto looking 83 Delta 88 into the GM dealer for an oil change. As sort of an experiment I didn't let them know I knew a thing about cars, didn't ask what oil they would put in or anything. Waited to see if they would inform me of any problems with the car or ask if i wanted some thicker oil in my old rustbucket. In the end I got called when my car was ready, saw they used 5w30 and all they noted on work order was that engine had oil leaks (which it does but does not use much). So apparently this GM dealer does not even worry about using 5w30 in a beat up 27 year old car with a ton of miles and oil leaks, whereas the Ford dealership I used to work at would always ask the customer if they wanted 10w30 in an older vehicle.

I'm not sure if I can see 10w30 being a benefit. Does the 5w30 work any better during a cold start even in the summer?

 

[DragRace]

I "used to" use 10w30 in summer months. Since buying the Explorer with the v6, I have since just used a synthetic 5w30 during summer-winter, and have had 0 problems / issues.

 

[TallPaul]

Originally Posted By: SnakeOil
Sometimes 5w30's have better base stocks than the 10w30's. I say you are throwing the dice.
This was (and maybe still is) true of Durablend according to MSDSs. So if the 5w30 has better basestocks, I'll run a synthetic 10w30.

 

[ARB1977]

I have yet to use 10W oil in my Tacoma. This summer im using 0W30. In the Jetta im giving 10W40 a try.

 

[eljefino]

Originally Posted By: TallPaul
Originally Posted By: SnakeOil
Sometimes 5w30's have better base stocks than the 10w30's. I say you are throwing the dice.
This was (and maybe still is) true of Durablend according to MSDSs. So if the 5w30 has better basestocks, I'll run a synthetic 10w30.

When SM came out I read that only 10w30 and thicker could be met with a measurable percentage of group I. So a ghetto blender like Coastal could take a decent 5w30 and dilute it with some grp I and wind up with 10w30 that they'd sell for the same price.

I wouldn't mind if they managed to slip the stuff into dollar tree for $1/qt, but they get the same $$$ and it strikes me as a worse deal.

Look at VOAs and UOAs for the same thing, IIRC havoline 5w30 had or has a lot more moly than their 10w30... cool!

 

[Art_Vandelay]

Originally Posted By: Max_Wander
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.

varnish comes from one main source, VII's.


Are you saying this leads to oil consumption?

I thought something like GC 0W-30 was more sheer stable than a
5W-30 or even 10W-30 for that matter? Does the high PAO content make that oil an exception to what you are saying?

 

[lawdogg]

Originally Posted By: Art_Vandelay
Does the high PAO content make that oil an exception to what you are saying?


I believe PAO based oil (Grp.IV), or I suppose even hydrocracked Grp.III + PAO ('synthetic') won't need as many VIIs for a given spread as a Grp.III. Since VIIs shear, normally, I think he's saying that PAO decreases the need for VIIs which decreases the potential shear of the oil.

Of course this is, afaik, limited to PCMOs, as the Grp.III HDEOs I've seen (with either a 20 or 15 spread) are just as resistant to shear as the Grp.IVs and Vs.

 

[Bambam]

Originally Posted By: Doug Hillary
Hi,
Bambam - You said this;
"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."

This is why multigrade lubricants were introduced around 60 years ago. I am still amazed that people change multigrade lubricants seasonally where the Manufacturer prescribes them for year round use



So would you be worried about to many VII's in an oil?


Side note: Thanks to DrAEHaas for pm'ing me a few links to articles,they will be very helpful.

 

[Greaser]

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.
If the HDEO is rated for SL and now SM and your engine manufacturer says to use this type of oil then I wouldn't worry.Running a 15W-40 in a little 4 banger might be a bit thick.I have three cats on my 2001 Jeep and every two years I must have a Emission test to get a license.The numbers have either stayed pretty much the same or have gone down on the tests so my cats are fine.