Just wondering what everyone thinks about Amsoil and their recommended 25,000 mile oil changes. Keep in mind I only put 12,000-15,000 miles on the Bonneville in one year.

Lets do some math...

5qt jug of Pennzoil Platinum ~$25
Purolator PureOne Filter ~$7
Total for one oil change $32

$32 x 4 changes per year = $128/year currently


5qts Amsoil Signature Series $50
Amsoil Ea Filter $17
Shipping/Taxes $15
Total $82/year

So, I could cut my oil costs by over $45 by running Amsoil Synthetic. Another option would be to stretch my intervals to 5000 miles on my current oil and filter combination and see what happens.

What do you think? I have about 1700 miles before my next OC so I have some time to think about it...

I would stick to standard oil and standard change intervals. 25k miles seems like a lot for a 3800. I'm not entirely sure how amsoil claims to be able to hold more contaminants to that great of a degree, but I'm calling foul. I know for a fact my L67 starts to sound and feel different if I wait more than ~3k miles to change the oil. Last oil change I used mobile 1 synthetic and went 4500 miles and it didn't run as smooth as it did after the oil change.

My main thought here is the oil may last that long as far as lubricating goes. however, the oil level will drop slowly, as well as get dirty. And the filter will collect that dirt but will over time get plugged up. Do the math, 3000 mile oil changes, and change filters every other oil change. So it lasts 6000 miles. I will go perhaps 9000 on a oil change with synthetic, and change the filter on every oil change.

To be honest I didn't read anything besides the title, with saying that. . . . .

I run AMSOil 10W30 in my bonnie and change the filter every 7500 miles. Read that carefully, I just change the filter, and top off the oil. It normally takes a full quart of oil to fill her back up after the filter change. I have sent the oil off for analysis twice now and have gotten the all good back both times.

Amsoil filters claim to have synthetic filter media that can hold more contaminants without breaking down, as they claim paper filter media can/will do. That said, I already don't use a standard paper filter... Purolator Claims that PureOne media is an exclusive "micronic" media that has 99.9% efficiency.

Since I'm already hesitant about going a whole year on one oil change, I think I'll just try to stretch my intervals to 4 or 5000 miles and see what happens.

For the record, I do own an Amsoil Ea Foam air filter that is supposed to last up to 4 years and flow more than a standard paper filter while trapping more contaminants than paper or wet gauze (K&N).

I dont buy the "our filter hold more dirt longer", thats why I change my filter every 7500 miles still and just use a WIX filter.

I'm with Trent. just because it can hold more dirt don't mean it will allow the oil to flow threw as easy as it should.

Exactly what I was thinking. Filters get clogged. That'* their job anyways, right?

FWIW, I use the filters for the 4.3 Blazer which allow for a bit more filter area. Either way, the oil still comes out dirty after 3k miles. I'm starting to think about changing just the filter every 3k and maybe letting the oil go 6k between changes, sort of like what Trent said. With a fresh filter the oil should stay clean longer, at least I would hope.

In the end it all comes down to saving some money... without hurting the car in the long run.

Hmm.. Maybe I'm just paranoid, but I run Full Synthetic Mobil one and Mobil one filters and change my oil every 3000. If I know I'm going to go over before I have a chance to change it I'll even change it before 3000.

Guess it just doesn't seem worth risking the engine to me. I'd rather be extra clean.

Oil is alive with reactions as the chemical soup it becomes gets heated and combined with hydrocarbons, nitric acid blah blah blah..... 25,000 miles????? IS there any time requirement. I use synthetic, change by the oil monitor (9xxx miles per cycle) and at 50k my Northstar still purrs even though I have made it exercise a time or two.