Mobil 1 extended

[Dyno247365]

Okay i've always been told to change my oil every 3,000 miles, in a normal car. This stuff is made for normal cars, but what happens when this oil that supposedly lasts for 15k miles is changed every 3k?

[KiwiBacon]

Originally Posted by Dyno247365

Okay i've always been told to change my oil every 3,000 miles, in a normal car. This stuff is made for normal cars, but what happens when this oil that supposedly lasts for 15k miles is changed every 3k?

Your wallet becomes a whole lot lighter and stays that way until your habits change.

[GreyGoose006]

what i'm more worried about is what leaving the same oil in your engine for 15,000 miles does to your engine.
its not hard to change the oil in a car, nor is it expensive.
although the oil *can* lubricate for 15,000 miles, what about all the shit that builds up in it and puts extra wear on the engine??? oil comes out black for a reason.

isnt there oil that lasts for 75,000 miles?
how much would be left after 75,000 miles?
in my car, about half a quart.

[Steel]

well obviously you gotta keep it topped off between oil changes. But modern synthetics resist breakdown LOT better than dino-oils( as well as better shear properties, better lubrication, better hot metal affinity, etc), that's why its o.k. to leave them in for 15k miles or so (and its also why they're so expensive!). BUT! you SHOULD change your filter every ~5k-~7.5k miles or so to keep the oil flowing.

You should see the VW 507.00 synthetic oils that they use for their diesels. People go 20-25 thousand miles before changing the oil with no problems as far as the oil analysis tests were concerned.

[bluevp00]

Thats nothing, Mercedes did a test of their new big-rig diesel engines, and part of the test was not changing the oil for nearly 100,000 miles. Just to show that the engine could take a beating.

[curtis73]

The 3000-mile oil change interval is a throwback to the 60s. Oil companies love it because you're buying too much oil. Manufacturers love it because you're definitely exceeding the need for oil changes, and if anything fails they can blame you for not changing it at exactly 3000. Qwiky Lubes love it because they make more money. Your president loves it because he lives for oil sales.

The more important factor is the car and the driving style. I have a Ford 302 with a lot of blowby and I would suspect it needs new oil every 2000. My wife's Tercel still has stock compression numbers and her oil still looks like honey at 5000 so it probably tests just fine until 10,000.

Appearance won't tell you anything. Get it tested by a lab like Blackstone. I think a test costs something like $30 which is less than the cost of a synthetic oil change. That way you can establish proper intervals for your car. That way you're also not wasting oil, killing baby seals, and harpooning whales while lining the president's pocket.

Also, if you're buying synthetic oil, make sure its truly synthetic. In order to be called synthetic, an oil merely has to meet API standards for levels of impurities. Cheaper on-the-shelf synthetics like Castrol, Valvoline, Havoline, etc are still made from base stock that came from under the ground. They have just been filtered and refined in such a way that they qualify to be called synthetic. Oils like Mobil1, Royal Purple, and Amsoil are true synthetics. They are born in a lab from synthetically produced esters.

[UncleBob]

mobile1 extended life is damn good oil. I use it in all my bike engines (very modified engines at that) and change it every 10K miles. I have been into my engines enough to see what kind of long term results this produces. Compared to the dyno oils I used to use, changing it every 3K miles, there is no comparison, when comparing plain bearing wear.

[Steel]

Yep. Synthetic oils these days are the bees knees. I use them in all of my cars (except the 3 cylinder oil eating civic, for quite obvious reasons).

I had especially good results with my DR650, because its an oil and air cooled engine, i liked the thought of an oil that didnt break down at high temperatures (idling in traffic on a hot summer day and such) And my bike seemed a bit more responsive... but that's the butt-dyno talking.

[Dyno247365]

What did you call me??

okay enough with the name calling, I think next time I'm gonna switch to Mobil1, 10,000 miles, that's really nice. I think my 240sx has a blend right now. It's been so long since I've been in a garage. I can't frickin take it anymore!!

[Steel]

name calling?

[KiwiBacon]

Originally Posted by Steel

name calling?

Sorry jokes over, you missed it.

FWIW, my nissan owners manual (QG18DE engine) recommends oil changes every 15,000km (or annually, whichever occurs first).

[GreyGoose006]

well i know that the oil can hold up for that long, but i would just be worried that there was so much junk in it that it was still not performing at its best. maybe i'm just over cautious/paranoid

[Steel]

Originally Posted by GreyGoose006

well i know that the oil can hold up for that long, but i would just be worried that there was so much junk in it that it was still not performing at its best. maybe i'm just over cautious/paranoid

Then i'd be more worried about the oil filter.

[2.2 Straight six]

Originally Posted by GreyGoose006

what about all the shit that builds up in it and puts extra wear on the engine???

it gets caught by the oil filter to prevent damage.

[GreyGoose006]

well yeah, but there is stuff the oil filter misses isnt there?
with clearances in the thousandth of an inch in an engine, it seems that little pieces of grit would cause problems.
isnt there a lot of gasoline in old motor oil?
nevermind.