I am installing a rebuilt motor in my PT Cruiser and want your opinion on rather to use synthetic or conventional oil. Is it true that you can go 10,000 between changes with synthetic?
Thanks,
Chuck

I'd never go 10K miles on any oil. I run Delo in my 02 Cummins & change it (11 quarts) every 3500. I can tell a big difference w/ fresh oil. Check out www.bobistheoilguy.com A website totally devoted to oils & there's a lot of good info there for you.

I run 7500 miles between changes on my 05 ram with synthetic, no problems.

After (initial cam/lifter 30 min) breakin, I do synthetic w zinc additive changed 4X yearly. Expensive but the best of both worlds: better quality from synthetics/frequent changes to eliminate contaminates.

I wouldn't go 10k miles on oil, 5k miles is my upper limit, and only on my newer car with a low-miles engine. I mainly chose synthetic because I do a lot of short trips and figure syn can only help.

....but there are SOME PEOPLE ...with a certain brand of oil (the name starts with the letter A ) ... that claim you can go TWENTY FIVE THOUSAND MILES between oil changes !

I'm old fashion i like good old oil. But i agree it is more important to keep it changed then which type you use. I change mine every 3000 i don't care what the owners manual recomends.

I have two new vehicles, from two different manufacturers, both have oil monitoring systems.

7500 miles seems to be about the average life of the oil, synthetic or conventional. But this is on modern, computer controlled vehicles. Older carbed cars, I'd limit to 5000 miles max.

Depending on your driving habits (city versus highway) yes you can go 10,000 or more between oil changes. GM has proven this with conventional oil and their oil monitoring system.

Almost all 2005 and later General Motors vehicles are equipped with its Oil Life System, which makes use of a color-coded system to alert the driver when it’s time to change the oil. A “yellow” condition indicates that it’s time to think about changing the oil, while a “red” condition indicates that the oil is past its service life. According to GM, the typical drain interval for vehicles equipped with the Oil Life System is 8,500 miles, which will result in a savings of 6.6 million gallons of oil and $145 million for 2005 model-year drivers over the lives of their vehicles.

General Motors is actively seeking to extend oil drain intervals even further. In fact, the company recently asserted that 20,000 mile oil drain intervals are possible with existing engine technology and synthetic oils meeting current specifications, while 30,000 mile oil change intervals are achievable with appropriate motor oil quality and minor engine modifications.

“Drain intervals are a very specific goal for GM, and are being managed in a logical and planned fashion,” says James A Spearot, director of GM’s Chemical & Environmental Sciences Laboratory in Warren, Mich. “Longer drain intervals are desirable to meet customer demands for reduced maintenance and convenience, and for the environmental benefits that come with less oil handling. And, in the end, longer drain intervals will help us with our warranty protection goals.”

GM has gone to a percentage display, at least on my 08 GM product, as does the 09 Ford I drive.

I do not want to repeat the whole thread so just read the post I made about needing a tech for my 2000 3.3 minvan. I found the problem to be oil related. I used conventional in it. I may be switching back to mobil 1 syn. after this experience. I changed oil at 3000 miles religiously.
I had a 92 Dodge Cummings with the Amsiol extended drain system on and I went 50,000 between oil changes. I changed the bypass filter every 10,000 and the full flow every 20,000. I sent the oil in for analysis every time I changed. Put 220,000 on it with no problem and it was mostly short trip driving. The guy I sold it too is still driving it. I did take off the system and they use regular oil.
One of the big problems I see is that they change the makeup of oil to meet EPA rules all the time and it changes the makeup of the oils and we don't even know it.

Deansrr,
(what happen to old motor?)

The motor blew a headgasket and while checking it out I found that I had 100# of compression on the best cylinder and it was confirmed that it was not the head gasket leak interfering with that cylinder when I wet compression tested and it only increased the compression by about 7#. It had 182000 miles on it and I want to keep the car because I love it and I don't want to be tearing it down to rebuild in six months so I am just going for the gusto! I cahnged the oil every 3000-4000 miles using castrol high milage.
Chuck

I drive about 50k miles a year, mostly highway. I always use Mobil 1 Extended Performance and change oil every 15,000 miles. I've got 140,000 on my '07 Altima and have had zero issues with it. Just my .

Go on Youtube and do a search for Red Green doing an "oil change." Funny as Hell.........he takes the drain plug out, and a few drops come out.........

Thank all of you for your responses...Keep em comin'.
This is the most active forum I have ever been on. You guy's are great!
Chuck

There are a lot of good motor oils that can easily handle 10k oil change intervals. As already mentioned, bobistheoilguy.com is a great place to learn about motor oil. If you go there, you can find a whole section devoted to Used Oil Analysis where many have successfully ran the right motor oil, oil filter, and air filter to extend there oil change much, much past 3,000-miles. We are no longer talking about 1930s technology where the 3,000-mile oil change recommendation originated from.

Another short article of interest: 3,000-Mile Oil Change Comes Under Fire - Article link

It is not the oil wearing out that the problem is, it is the contaminants that get ito the oil that do the damage and there are contaminants that the filter cannot take care of. Even the owners manuals that come with the Dakota we hav and the Chrysler van recommend oil changes at no more that 3000 miles under normal driving conditions, 7500 miles if under ideal driving conditions, like continual hiway miles.
The same recommendation whether using regular or sythetic oils. The same contaminants get into the oil either way.
It really is funny how you people can spend so much money on an engine or vehicle and then try to scrimp a couple of bucks on an oil change by extending the mileage intervals of a change. Oil is still cheap maintenance.

Considering all the drivers I have to maintain I use whatever conventional motor oil I can find on sale that is somewhat name brand. Lately AutoZone had had Peak brand oil on sale with a filter for $12.99. I currently have 5 cars that I change the oil on every 3000 miles and they all run fine.

I'm not saying that there isnt a difference in oils but I think for the average daily driver it makes no difference.

The extended stuff is a bunch of BS because the contaminates are still there after the filter, carbons and fuel and all the crap in the blow by. On the GTX I run Rotella and an additive and I change the oil every 2000 miles.

When/if I move up to a newer vehicle I may go to a synthetic but I'd never run it for more than 3000 miles.

Like someone said, its cheap maintenance