# Probable Interval for Castrol 0W-30

#### HondaRD

I know we have not seen any UOA on this oil yet, but if it were to perform like it appears from the VOA, would it be safe to take to it up to the 6,000 mile or maybe a 10,000 mile interval with it's pretty high TBN?

#### buster

Probably about 100 miles. Well, it's just to hard to predict. TBN isn't the only indicator. I think it will be a very good oil.

#### Patman

Staff member
My plan on my sister's car is to run the first interval to 5 or 6k, then look at the UOA to see if it's safe to go longer. I'm hoping it'll be able to handle 12k drains, then I'll just change her oil twice a year.

#### Dr. T

Agreed...from what I've seen BMW's request oil service at 15k km (10k mi.)...same for friend's C-Class M-B requiring 229.1/3...that interval would seem on target.

#### TooSlick

HondaRD, I think its probably comparable to Mobil 1, so I'd use the same drain interval you'd run with that oil. The TBN on the spec sheet for this oil is about 10.5, which seems accurate given the additive chemistry. As I recall, Blackstone got a figure of 14.5 for this formulation, which I think is highly doubtful; given the levels of calcium and magnesium in the formulation. If you are running this in a high revving Honda/Acura engine, I think I'd test it after 6k-7k miles and adjust the change interval accordingly. Running 10k miles in a BMW or Mercedes with a 7.5 to 8.0 quart sump is very different from running 10k miles in a Honda with a 4.0 quart sump. I'd use my "Oil Change Interval Formula" as a starting point, with the same constant I'd put in for Mobil 1: OCI(miles) = (80)(average mpg)(sump in quarts)(cubic inches/Hp) I think that will get you in the ballpark as far as a reasonable change interval .... Tooslick

#### HondaRD

Thanks TooSlick for the suggestion and formula. I was not really considering the sump capacity as a factor. From your formula, it would appear that I should change it out at 6,600 miles. I was contemplating on the cost justification on continuing the use of synthetic oils but can only see it worth while if I can go at least 7,500 miles, which I think is within reason. Since money is tight these days, I might just use something like chevron supreme and change it every 3,000 miles to save a few bucks, but I just wonder if Dino oil can handle engine speeds of 8,000 RPM well enough to warrant any cost savings. Thanks again everyone for you comments...

#### Quick_lude

quote:
Originally posted by TooSlick: OCI(miles) = (80)(average mpg)(sump in quarts)(cubic inches/Hp) I think that will get you in the ballpark as far as a reasonable change interval .... Tooslick
Hey Tooslick any chance to convert this formula to metric? I remember you posting this before.. don't remember if you already had the metric version there.. The gallon on mpg, is that a 4.5L gallon? 1 quart is 946ml correct? [ June 03, 2003, 06:12 PM: Message edited by: Quick_lude ]

#### cangreylegend

What about fuel savings? Factor in say 2%. What does that give you? Cleaner engine? It looks more like a tossup and if anything might lean to SLX. What about future generations pollution problem?

#### Quick_lude

Using 4.5L = 1 gal, 946ml = 1 quart I got 7500 miles for my Honda Prelude 200hp, 131 cubic inches engine. Interesting.