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1985-1998 [Subscribe to Daily Digest] |
>> Interesting that you selected 15w40 vs 10w40 eventhough the protection would theoretically be similar at operating temp. Must be warm down there in LA.
Yeah, summers are tough here, and it rarely gets below 25°F in winter.
>> I wonder why they would market two different products with such similar viscosity curves.
The 15w40 is a common diesel specification, and I think that is its target market. One RP person once suggested that the 15w40 had a slightly better additive package, then later denied that he implied that, but others at RP claim that this isn't true and either will work fine. Both are diesel rated.
I traditionally like the shorter visocity ranges, as 15w40 is 25 points vs. 30 for 10w40. In the old days, perhaps less relevant now, a higher spread meant more VI's, which was/is bad for the oil's longevity. But that's the old school of thought that certainly isn't as important today, and when I finish this 5 gal. pale I'll probably go with 10w40.
Keep in mind that my Aero stays in an enclosed, dehumidified garage that rarely gets below 55°F, so most cold cranking is under very favorable conditions. I think that will take some time, though, as with 10k intervals a 5-gal pale goes a long way.
>> I use RP 10w40 here in Oregon simply because that is what the local NAPA has most in stock. It would cost me more to have stuff shipped in.
I just bought a pale of Nitro-50 for my Harley at $137 for a 5-gal pale from my distributor (wholesale), and Oiltown would've cost about $20 less even with shipping factored in. My location makes Oiltown a viable choice, but apparently this isn't the case on the West Coast because of shipping costs.
>> My concern is that with my 919kT that I have to make lots of shorter trips (<5 miles 1way) to work and so forth and I may not have the ideal viscosity for my use(i.e better startup protection).
How cold do you get up there in winter?
>> I found it interesting that the 5w30 was actually more $$$(slightly) that the others that they were offering (10w40,15w40).
I didn't know that. If I'm correct, your winters aren't much more severe that we get here in LA (the state), and your summers not nearly so hot. If you rarely get above 85° in summer, I think you could go with 10w30 year-round. I'd probably still use 10w40 since I'm not a thin-oil kind of guy.
>> I'm thinking of changing to the 5w30 this fall, for both better startup protection and better mileage. Any thoughs on mileage increase? 5% for each significant jump in vis?
I'd be surprised if you noticed any significant difference over 10w40, but it'd be interesting to try it. Unfortunately, I can't imagine a real-world test to compare the two, since you'd be using the 5w30 in completely different conditions, probably much cooler that would lower mileage in itself and bias the test.
Personally, I like using one viscosity here because I use a 10k drain interval, and with that procedure I can't be assured of timing the changes to correspond with the seasons. However, those who live up north and experience hot summers and very cold winters may really need to make these visocity changes to fit the season.
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