It's more economical as it tells me something. Just changing your oil is like conducting a long term experiment and throwing away the results. 
My interval is whenever I feel like it, and will be more often as it wears. 

-craig

On Dec 7, 2012, at 11:05 AM, Alistair Bell <albell@SHAW.CA> wrote:

> So you send out you van out for testing on a schedule? And that is more economical than changing your oil?
> 
> Alistair
> 
> 
> 
> On 2012-12-07, at 4:16 AM, phishman068@gmail.com wrote:
> 
>> Hmm....
>> I guess you guys don't believe in or have experience with oil testing?
>> Perhaps you didn't notice that piece of info where I said I have had the oil tested and its been passing?
>> 
>> I no longer believe in service intervals assigned to the masses when testing and good science can prove the exact conditions on an individual basis. 
>> 
>> One of the marine Diesel engines on a boat I run has 26gallons of expensive and specialized oil. We do not change it because "it's time", we change it because tests tell us it's time. The same can apply to a vehicle, an oil change just doesn't cost thousands of dollars in the case of the Zetec. 
>> 
>> I'm not throwing away good oil, and so far I've proven in my application the service interval is infact a great deal higher than what's "suggested". 
>> 
>> -craig
>