Toyota car and truck forums

Hello to all,
Here is a good question for everyone they say now to change your oil with (regular non synthetic oil) every 3k or so. So my question then is why does it say in my owners manual for my 87 Camry to change the oil every 6k and in my 1990 Honda its says every 7,5k? This does not make any sense to me there is little difference in the oil from back then and why should I change it every 3k if the owners manual is telling me change it every 6k? Please advise here and give input as I am confused thanks for your help.
Dave

There is no set oil change interval - it is determined by the driving conditions and the condition of the engine. The older service intervals were just a ballpark figure - for most conditions, those mileage figures were perfectly valid. Once you add in some stop and go traffic, extended idling, and/or heavy engine loads - then shortening the interval is recommended. Most service schedules have a "normal" conditions guideline and one for "severe service" conditions.

With the formulations of modern conventional motor oil - 3K miles is excessively short for most people. Only way to tell for sure is it send in a used motor oil sampled to be chemically tested. Some cars can run longer on an oil change, some like shorter changes.

My current cars - I generally run a 7500-8000 mile oil change interval (synthetic motor oil). I have tested and run the oil out as long as 18K miles (synthetic) for an interval - the oil additive pachage was pretty much spent at that point, but still offered good protection for the engine.

3000 mile interval is becoming less and less desireable - some still stick with it, and the oil companies are all for that, some are starting to stretch them out to 5000 mile intervals or more. Only way to find out where you stand is to test your motor oil. Good example is this lab - http://www.blackstone-labs.com/ - I use them for my UOAs. Runs about $22 a test, less if you buy testing in bulk. Normally I test once a year - just to see how things are.

Check out bobistheoilguy forums (http://www.bobistheoilguy.com) and carbible (http://www.carbibles.com/engineoil_bible.html) for additional information. Lots of good info in there - just have to wade through some of the sales pitches and self-preaching that occurs there, but good info nonetheless.

Thanks very much for all that info sounds like 5k for me.
Dave

I'm with FIshexpo but I'll add that you can, at the end of your next 5,000 miles, send a sample of your oil to a lab (e.g. Blackstone), and they will, if you want, analyze your oil and find out the remaining lifespan in terms of viscosity and additive effectiveness for under $30. Its well worth it; you mihgt be able to stretch to 7,500 miles or more.

GM's research shows that most people could get away with 10,000 mile intervals! They have a program that tells you when to change your oil built into their cars now. Most of them anyway.

My own Toyota's recommendation was 6,000 miles. The DEALER wanted 3,000. They do OK from oil changes apparently.

Thanks very much for the info Yeah I agree 3k is way to soon. I think with regular oil 5-7k is just fine.