3k oil chages came around in the 40's. Oils have advanced since then, and filters have both been added and improved. (Although if you own an older VW Beetle, you might not have an oil filter unless you put in an aftermarket kit.)

In Consumer Reports 4.5 million mile test, they saw no reason to go with quicker oil changes and synthetic oil. That being said, I use 5k changes with synthetic oil and Puralator pureOne filters, since the guys that tear them apart on the web and post pictures all say they're a good deal, and universally hate the cheap Fram filters. (Expensive Fram's do a little better).


Do your own investigation, YMMV, and here's the consumer's report article. It also talks about additives:
http://www.xs11.com/stories/croil96.shtml

There's another Consumers Reports reprint on the web--I want this job! Driving a car without oil to see if the "oil miracles" you see on TV work. Of course, the answer is no.
http://xcelplus.com/industry_info/consumerreport.htm

I voted for synthetic because thats what I start using on my new eng. since I spended alot of money on it, I want to make sure that it'll last a long time. before I used petrol on the 4 cl. and I changed the oil almost every 5k.

You should tell them how much oil you add between changes, and they take that into account when they do the analysis.

I've used them once, a few years back, and plan on sending a sample again real soon. I'd say the results are a pretty good indicator, especially if they find traces of anti-freeze in the oil.

Twenty bucks, how can you go wrong?

If someone is adding a lot of oil between changes, the use of synthetic doesn't make sense. It is a lot of money to spend that is getting sent out the tail pipe. If my Rodeo didn't burn oil I'd make the switch. I just switched over to pennzoil blend. So far I like it.

I agree, I like the idea of an oil analysis. I am going to do one mid-summer. It's a great way to keep an eye on the internals.


marc

|I would only use the exstended oil change if I was using the Amsoil duel filter set-up. Oil analiss (sp) has been around for a long time. It will tell you how much sand your K&N is passing.

I use Mobel 1 only in my WRX.

Oil change before smog check in my old troopers is Mobel 1, add Delo 10-40 there after.

Redline in diffs and transmissions.

I understand your point about cost to keep adding synthetic but I still feel more comfortable doing so, especially if oil gets a little low between refills. It doesn't take long for a quart to burn off in 1000 miles without forgeting to top off.

I've requested sample kit and we'll find out soon enough.

is a switch back to blend from mobil one no longer an option? Just curious cause I like the sound of mobil one but I am ready to stop wasting money on adding oil. I may be burning it excessivley but that is probably another issue

Expect to wait a few weeks for your kit... but once you send the sample in, they are quick about getting yer results back to ya.

"how much sand your K&N is passing" <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />
that's funny! (and probably quite true!)

Dino oil (cheaper and works just as good up to 4-5K miles)
3-4K mile changes w/ filter.

Last time I tore into an engine, it was one my 16v VW which I ran the same oil and intervals driving the snot out of it, and it looked like new inside at 180K miles. Only tore into it for more displacement.

Long interval oil changes scare me. Especially after seeing some stuff like this...

Click Me

I understand oil analysis in aircraft where there's dire consequences for engine failure--we did it after ever "x" flying hours in the military (where "x" varied by aircraft, but could be as low as 25 flying hours).

It consistancy gives great charts. If you find a certain metal concentration changing rapidly, you either rubbed a coin between your fingers and dripped some oil on it, or you had increasing internal wear. (Note: odd but not catostrophic readings put you up for a cold sample, then another hot one after the next flight)

All readings were taken within 15-30 minutes after engine shutdown (varied by aircraft), for consistancy, with a set proceedure to get "middle of the reservoir" oil.

And you reset your graphs after oil changes (although it tracked across them)

But random sample intervals in a car engine, probably with oil changes inbetween and a wide variety of miles after oil change when taking the sample....what will it really tell you? A check 4k after oil change, then another 1k after a different oil change, would make it seem like your engine is self-healing.

If you have a gross failure, like anti-freeze, it probably gives you a little bit of a heads up. If you have a gross failure like metal wear....you don't know what the part is unless they also have metals composition for all the vehicles (you could pinpoint the part in a military engine). And if you don't know for certain, most people aren't going to tear the engine apart on a hunch.

If you don't sample often and consistantly, it's not really of much value. I'll just wait for the classic symptoms and save my $$.

If there's a better reason to do it, please let me know. I'm obviously ignorant of why to do it at random intervals on car engines.