10W-40 making a come back?

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I was at Kragen's today and was marveling at their oil selection and fully stocked shelves. I then noticed something missing from the picture; the long row where the 10W-40 Chevron Supreme usually sits, was completely empty. I asked the store clerk if they had any more; his immediate reply was: "No we're completely out, because the stuff flies off the shelves." [Eek!]
 
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Just cause of summer is all. I use to run 10w-40 in the summer in a Chevy scottsdale 350 V8 due to the fact that it carried an 11' camper and a 4,000 LB boat. In the winter, I switched back to 10w-30
 
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There's half a world of performance difference between Euro 0W-40 and 5W-40 synthetic motor oils and the U.S. 10W-40 conventional motor oils.
 
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although a lot of people here think that because of the abundance of visc.improvers 10/40 dino oils have, you actually have a 10/30 after about 1500 miles, with a bunch of broken down visc.improvers floating around...that can't be a good thing, if that's a fact.
 
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quote:
Originally posted by Ray H: There's half a world of performance difference between Euro 0W-40 and 5W-40 synthetic motor oils and the U.S. 10W-40 conventional motor oils.
What about HDEO's and HM 40 weights???
 
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Most American and Japanese cars recommend 5w30 or even 5w20 now. European cars often recommend 5w40 or 0w40 synthetic. Why would 10w40 be making a comeback? It seems too thick for domestics and Japanese (particularly at cold start), and not thick enough for European cars.
 

KW

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I used 10W30 for years but last year I moved everything over to 10W40 as everything I have nowadays is fairly high mileage and is noisy with 10W30. I do use a synthetic 10W40 though.
 
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quote:
Originally posted by 97tbird: although a lot of people here think that because of the abundance of visc.improvers 10/40 dino oils have, you actually have a 10/30 after about 1500 miles, ...
I don't think that happens that much anymore. I have a UOA on Maxlife 10w40 about three years ago. At 3000 miles it was still a 10w40 at 68.2 SUS viscosity if anyone can convert (one thing I don't like about Blackstone Labs). Blackstone stated the range for a 10w40 is 65 - 76 SUS. Now I ran some 10w40 Durablend for 3000 miles last fall and it ended up 12.6 cSt, which is the rock bottom of the 10w40 range, so there was some loss of viscosity (about 1 cSt or so). Check out this old thread: 10w40 Gets a Bad Rap. [ April 30, 2006, 08:57 AM: Message edited by: TallPaul ]
 
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My father's 1988 Chrysler he uses to bang around town in states specifically in the manual not to use 10W-40. It recommends 5W-30 but also says 10W-30, 15W-40 and SAE30 are all fine in warmer weather. So there is some belief that 10W-40 can cause problems that goes back a while. But I thought 10W-40 was the single biggest selling grade of oil in the US at one time (the 90's).
 
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Yeah, in my saabs. I've fluctuated between 15W50 to 10W40 to 0W40 to 10W30 (the recommended grade in my 900) to 5W30 to 5W20. All those were M1.
 
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Never noticed a difference (especially with the loud muffler). It was 5w30 before and 10w40 after. But this winter I ran 10w30 Citgo Ultralife 12 cSt and it seems to maintain oil pressure quite well, though I haven't had any 80 or 90 F days yet. In theory, should the engine be quieter when the oil is not fully warmed up? Again, I never noticed a difference, but that on cold start it seems rather loud--maybe because it revs up at first.
 
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My VW Passat 1.8t survived at least 5 OCI's of 5000 miles each using 10w-40 Castrol GTX. It now has 102,000 miles and runs great (when it doesn't have some type of sensor on the blink [freaknout] ) All other oils were M1 10w-30, 0w-40, Synpower 5w-40, Maxlife Syn 5w-30, and currently on my fourth round of GC [Cool]
 
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quote:
Originally posted by GoldenRod: Has anyone tried a 10W-40 in an engine where the manufacturer has mandated it to use 10W-30?
My F150 manual says to use 10w30 and gives no other options. But both 10w40 runs I mentioned above are on the F150.
 

GoldenRod

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TallPaul, Do you think your truck runs a little smoother and quieter with the 10W-40 as opposed to 10W-30?
 
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