Oil change according to analysis only

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Apr 27, 2003
Austin, TX
Does anyone here change their oil solely based on indications of Oil analysis?

For the past 3 years I've been on a 1-year change interval with Amsoil and without exception the oil is always suitable for continued use. The most I've gone in a year is 15K or so.

Any thoughts on going until analysis indicates that a change is needed? Any perils associated with this? How long could it go?

How long? 5-10 years or more, depending on usage. I think you will find people here are generally notoriously conservative, some even breaking out with anxiety and OCD dipstick checking once they cross the 3 month/3k mi brainwashed OCI that their grandfathers used that hasn't been recommended in any new car manual for the past 25 years.
Nope, I very rarely ever do them any more.

I just shoot for 10K and if the budget is not there or I need to go out of town or other life issues happen, then I change it whenever I can and most likely before 16K. Otherwise, if I know for instance, my last two OCIs were going to fall in the 14-16K range if I didnt change them at that time so the last two were at 8K each, the one now has over 5K and I did this to time it with my life issues, like court dates for tickets and for going to see parents and going to see Bro)In)law, and the likes I knew I had to change it then i.e. 8 or else be over for sure and not have an emergency cushion of a few K because of life.

For me anything between 8-12 is On time, and Fine.

You may shoot of 4-6-or 8K for your situation. I know from experience of many Oil Tests on similar trucks, what I can get away with, and I did several when the truck was new. And I'll run several between now and 100K or 120K to re-check things, but since mpg and performance has only gotten better the more miles I use my truck, just like most of mine, I feel safe

and if not, then you can
About the only time it would pay to do that is if you have a piece of equipment that holds alot of oil, such as a locomotive(400 gallons of lube oil!) For the average passenger car, it's cheaper to change the oil and filter than to do a UOA.

I maintain a fleet of 7 passenger vehicles, I used UOA to determine what OCI was appropriate for the driving conditions. After that was determined, there's no economic benefit to doing a UOA each OCI just to see if I can eek out another 1k or whatever. But I will continue to sample my GM 3.4L equipped vehicles to check for coolant leaks.
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