Calling car experts

[427Windsorman]

Quality synthetic oil can go up to 25K miles between changes. The filter will have to be changed more often. This also depends on how you use your vehicle, and what sort of load it is subjected to. Personally, I go from 5K to 7.5K miles between changes, depending on how I used my car since the last change.
If you change your oil every 2K miles, you are just throwing away money, unless you are really hard on your motor. If you are changing synthetic (quality synthetic) at anything less than 5K miles, you are throwing away your money. Quality conventional motor oil can go 4K to 5K between changes, but this depends on how you use your vehicle. Do you tow trailers, are you hard on your car, etc.
I only use conventional oil for a break in period, then switch to synthetic. Once I build a motor, I use the conventional for about 5K miles, but change after the first start-up/run-in, then at 200 miles, then at 2000 miles. A new car only needs to go about 3k to 5k miles before switching to synthetic. That allows the motor to break in properly first.
If you already have miles on the car, you should flush the motor when switching to synthetic. After that, it should be fine. On higher mileage motors, you need to check oil consumption after switching. This is due to piston ring wear, gasket seal issues, etc, associated with normal wear and tear with conventional oils. If you notice that you are using oil after the swap, switch to a synthetic blend, a heavier conventional oil, or a conventional high mileage formulation.

Additives are snake oil, and should be avoided at all costs.

If you want some further information, you can look here:

http://www.corral.net/forums/showthr...t=oil+ch ange

http://www.corral.net/forums/showthr...t=oil+ch ange

http://www.corral.net/forums/showthr...t=oil+ch ange

http://www.corral.net/forums/showthr...ht=synthet ic

http://www.corral.net/forums/showthr...ht=synthet ic

http://www.scuderiaciriani.com/rx7/oil_filter_study/

http://www.amsoil.com/lit/lng_article/index.htm

http://www.performanceoiltechnology....KeptSecret.htm

[The Real Bingo]

Even my old 1986 LTD can go 6000 miles on oil. It's not too healthy to wait that long, but cars these days can probably go 9000 miles on the same oil.

[Gutter Ball]

My co-worker says her 2003 car can go 4 months or 8,000K's between oil changes! I change my oil every 3 months or 6,000K's. I use synthetic in both my cars and haven't had any engine problems yet, but oil the pans on both cars did leak, since synthetic doesn't "gum" up to seal the leaks in the gasket.

Like Windsorman, I've read reports that PTFE (Teflon) is not a good oil additive....

http://www.technilube.com/sections/test/add_main.html

http://www.msgroup.org/TIP043.html

http://skepdic.com/slick50.html

But my friend also swears by them, so I dunno. Regular oil and filter changes are the way to go.

FYI: Our CIO changes her oil every month

[The Real Bingo]

It also depends on how you drive. If you torture the car, and accellerate violently, you will need to change the oil more frequently, but ease the accellerator down, and you can get better gas mileage, more mileage out of your oil, and you engine will last longer too.

[427Windsorman]

but ease the accelerator down, and you can get better gas mileage, more mileage out of your oil, and you engine will last longer too.

I have owned 8 Mustangs, and had over 150K (225K on one) on all of them, with no problems. Many of those miles were put on a 1/4 mile at a time.
Keep up with your preventive, and regular maintenance, and you will most likely never have a major engine failure.

I still went 5K to 7.5K with Amsoil on all of them, and never experienced a mechanical failure.

It is all about taking care of the vehicle. Do that, and it will take care of you.

Thanks for the reply, Ed

I don't use additives and prolly never will.. I'm just afraid of them. I drive hard and check my oil at least once a month and if it's starting to get dirty before the 3K mark, I'll go get it changed.. but I still get it changed at 3K.

I figure it can't hurt eh?

[Solid Snake]

Synthetic oil is supposed to go for one year or 7500 miles on normal engines. 5000 miles or six months for turbocharged or supercharged engines.