CONSUMER REPORTS did a study using New York City taxi's. They inspected engines after 150,000 miles of use. One test group changed the oil every 3000 and another every 7000 miles. They found absolutely ZERO difference in the wear on the engine between the two groups.

I change the oil in my 98 Dodge Ram QC 4x4 360 once per year or around 25,000 miles.  I use Amsoil with 2 full flow oil filters and the Amsoil bypass filter.  Total capacity is 8 quarts.

Synthetic oil is much more slippier than dyno juice, allows the engine to run cooler and with the bypass filter that filters down to the 1 micron level, there is no reason that +25,000 mile oil changes are not only reasonable, they make a heck of a lot more sense than changing the oil every 3,000 miles, especially when you consider that you have to dump that +5 quarts of used oil every 2-3 months.

My .02.

Merlin

Merlin, a good friend of mine does almost the same thing to his '91 Mustang GT. He keeps the oil (Amsoils)for about 25k and just changes the filter every 3k. He has about 95k on it and he's burning almost a quart of oil  every month.  I'm not sure if Amsoil is to blame, it could be many other things, but that system makes me sceptical.  

I just fill it to the brim with oil-it smokes a bit, but I know there is plenty of oil in it!!
What is this "filter" thing you speak of....

You bet,years ago i bought a slightly used, high dollar car. I wanted it to last beyond the payments. I changed the oil every 1500 miles,which was every two weeks,i think i got real after about six months and went back to 3000 miles for oil and filter.  That goes for my hunting rig also,which had the engine totally submerged in a river out in South Dakota. The engine was running when it went under.    Ben

Nightstalker, that's right!  Taxis are SEVERE condition, stop-and-go consistent wear.  That's why they make good models for a study.  Dumping oil is free.  The parts stores have drums there for you to use, simply take your container home with you.  What's a hassle in California is waiting 2 hours for an oil change I can do myself in my garage in about 5 minutes.  Next time you leave those oil change places, check your fluids.  They often don't!

Kingfish,

Its hard to discuss a vehicle I know very little about and have never seen, but:

Synthetic oil won't fix a worn, old or damaged engine (not that your friend's engine is, just a general comment).  Synthetic oil, since its much slippier and it flows into small cavities better, will leak out of small gasket leaks more than regular dyno juice.  

My wife's Pathfinder had +96,000 miles on it before I switched it to Amsoil.  It, too, uses about a quart a month also, but it did it with Castrol GTX also, so it had nothing to do with regular vs. synthetic.  With the Amsoil, I don't have to worry about when to change it, just check once a month and change it with the seasons (once in the spring, once in the fall, pretty simple).

BTW: I am an Amsoil dealer and no, I cannot give you my dealer # since I am using a Company PC and cannot use it for outside work (there's nothing stopping me from giving an opinion however, on my own time).

Regards,

Merlin

Merlin, I just mentioned what I saw.  First off, my friend's car was purchased new, he's the only owner.  As for car knowhow, he is a mech engineer who, in his college days, worked on the University's team that built a methane car for competition.  He might even know a little more than you (just a huntch).  Like I said before, there could have been other factors involved to his problems.  What I know?  Maybe not too much to an oil guy like you, but I know oil gets pretty dirty-regardless of how slippery it is.  Dirt = friction. Friction = wear   Period.

Went to the Amsoil web site-cripes!!!  could we find any more expensive oil!!!  I use Wesson in the winter and Crisco in the summer.

Kingfish,

I agree about the dirt.  That's why I use the Amsoil bypass filter.  It filters down to the 1 micron or lower level.  Most full flow go down to the 5-10 micron level.  Some say the small stuff does more damage than the 5-10 micron dirt that the full filters catch. Amsoil will only guarantee engines for 25,000 miles that are in good condition to begin with, use the proper oil and Amsoil filters and the filter changed at the 6 month mark.

BTW: I had my +25,000 mile oil tested by oil analysis.  Except for the water contamination, it was fine.  The water contamination was caused by the local (and only) Dodge dealer installing  1. a bad thermostat or 2) a 165 degree thermostat.  In other words the oil was not getting hot enough even with two radiator blockers on the engine.  

Cleatus, if you just look at the price per quart, yes, Amsoil will look expensive, as will any other synthetic oil.  Compare a yearly oil change with 2 filter changes with Amsoil filters  and oil (2 filters + 6 quarts oil) vs. the normal 3000-5000 mile change oil and filter change (25 quarts + 5 filters) and you will get a lot better cost analysis.  And your engine will be better protected, too.

If you can't find this cost analysis on the Amsoil website, let me know here and I'll reproduce it for you.

BTW, most Amsoil dealers will cut you some discount over the retail price or you could be a dealer for $20/year and get it at dealer price as I do.

Regards,

Merlin

Merlin, I'm not trying to say anything bad about Amsoil, but can you give me reasons why I should chose Amsoil over Mobil 1?  I mean, Porche, Corvettes, and a lot of other high performance cars come from the factory with Mobil 1.  Also, dont give me temps and #'s because we all know how tests are always trumped up by the manufacturer.  also, what about that 1,000,000 mile BMW on Mobil 1?  I know it wasnt subject to exact real life driving, but hey?  Just asking.

the unocal 76 stations in SoCal will take used oil, as should most places that change it. dont know if they charge to take it -- i just leave it on there doorstep in the middle of the night [:D]

I believe it is unlawful for you to just leave your used motor oil.  There is no charge to dispose of used motor oil, I believe that the State of Calif. charges a tax on motor oil to run this program.  If you don't know where to get rid of used motor oil in Calif, just ask around at the local service stations or car parts place, they will probably know of one that is local to you.

                                              Correct on all points!........[smoke]

                                              I believe in what i see, not what i read.............[heavy]

What they neglected to tell, was that the oil they were testing, was out of the third engine in the cab!!!!!..............[frag]

i just keep adding so i guess it is the same as changin every 3000.

                                            Which is exactly why the "cab report" was bogus.....if your motor is running constantly, and you are putting in 2 or 3 qts every 8 hours..(because of leakage).....you are in effect "changing" the oil on a regular, ongoing basis!!!!!