Does anyone know how many miles you can go between changes on a full synthetic oil and is it worth it?

 

Thanks guys! This is alot of good info and even though I will probably stick with the synthetic I wiil be changing it regularly and not the 7,500 to 10,000 miles changes the guys at work recommended. Thanks again

 

I've always changed mine a 6k miles. I just could never bring myself to go 7.5k or 10k between changes.

 

I plan on 5000miles tops

 

It's been said but 5000 tops here as well with Mobil 1 5w30.

 

Calendar time is a factor, too.

I change Mobil 1 5W-30 at 6,000 miles, but never longer than 6 months (April & October).
It's good to start the cold and hot seasons with fresh, clean oil.

 

This is good stuff. Thanks again. Also I have always wondered why time is a factor if you haven't reached the milage limit. Does it breakdown over time also?

 

Mobil has some oils out there now. They claim using them with their filters you can go up to 15,000 yes I said 15,000. They will even replace your engine if it fails for up to 200,000 miles. Personally I change it every 5,000 with mobil 1 becuase I tend to hammer on mine.

 

There is a company called Blackstone labs that will send you a free test kit. When you change your oil, get a sample and send it to them. They will tell you how the oil's chemistry is holding up. And you will definitely be surprised at what they tell you in most cases with synthetic. I think its something like $25 for each analysis. But they'll you send the test kit for free when you go to their website.

 

Follow your Oil Change indicator. It will tell you more about your oil life than simply watching the mileage.

The OCI is designed for conventional oil and is likely conservative. So with a good synthetic, you can safely add 25%, maybe even 50% more miles than the OCI indicates. Only a used oil analysis can really say for sure.


Consider this rough example (lifted from a BITOG post, link below)

Mileage has little to do with how oil is monitored, here is the idea:

Car 1:
If you drive 90% of the time on the highway lets say 1500 rpm an hour.
you engine sees 90,000 revolutions in that hour and you drive 60 miles.


Car 2:
If you drive around town, profiling with 90% of your driving in 1st, 2nd, and 3rd gear, taking 4,000 rpm on average. That's 240,000 revolutions of the engine in 1 hour and you only drive 30 miles.

Taking this out to 3 months , 90 days:
Car#1 3,600,000 rpms and 5400 miles

Car#2 21,600,000 rpms and 2700 miles

This represents 1 hour of driving a day for 90 days.
Car #2 sees 6 times the engine duty of car #1 and Only half the mileage

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