Don't change your oil!

[Dave M]

I stole this from another forum, so I can't vouch for it's authenticity, but it's an interesting read.



What does Mobil 1 have in common with a fine wine? They both get better with age.

This is a must read:

http://neptune.spacebears.com/cars/stories/mobil1.html

Among the more interesting quotes:

"Engine wear actually decreases as oil ages. This has also been substantiated in testing conducted by Ford Motor Co. and ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119. What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it."

"While the wear metals all accumulated steadily over the course of the test, the highest concentrations of accumulation per mile occurred in the first 3,000 miles of the test! From the 3,000-mile mark all the way to 18,000 miles, only lead showed an increase in per-mile wear beyond 3,000 miles. Yet even with an increased wear rate, lead wore the least in terms of absolute wear. For iron and copper, the longer the oil remained in service, the lower the wear rate got."

"Topping up the crankcase is a critical component of extended oil change intervals, and frequent filter changes are most likely the key to extreme-length intervals. The cumulative effect of even minor top-ups, let alone a filter change, substantially increases the longevity of the oil."

From another article:

"One interesting point is that fresh oil will have a
higher wear rate until the ZDDP antiwear is activated(oxidized). The
wear rates of some 60-70 oils that I have tested improves over the first
1000 miles or so.

Edward B. Kollin
exxon Research and Engineering Advanced Fuels and Lubes Group"

[Ken(Bone Breakin Chevy)]

well this makes a little more at ease with the engine life system on my new truck.

[95TransAm]

I myself haven't had the privledge to take apart many engines in my day...still a youngin. I do remember though Joe1320 saying how he could still see the cross honing on the inside of the cylinder walls on an LT1 with a lot of miles on it (well over 100k) due to the fact it was always taken care of (engine oil changed, filter, etc...). I've also heard the exact opposite on engines that didn't have their oil changed regularly.

I'm skeptical, but intrigued at the same time. I just don't understand how it could be true though.

[Joe 1320]

I cannot remember the source, but supposedly Mobil 1 synthetic is good for many more miles as long as the filter is regularly changed (3K miles) and the crankcase is topped off. Supposedly it's good for 15K miles when the above schedule is adhered to. I haven't had the guts to try it though. Overall, I'm pretty satisfied with the look of the motor whan I opened it up. 3K mile oil changes sure kept things looking clean and fresh.

[Steel2686]

I've always changed my Mobil 1 every 2,500 to 3,000 miles (depending on when I had time). Any problems I've ever had with any of my cars have always been non-engine related. Interesting article, however, I'll probably just stick to my regimine.

[Kevin - Blown 95 TA]

While the lubrication properties of the oil might not be worn out at 3000 miles, the oil picks up contaminants, acids, & fuel. The contaminants can mostly be filtered out, but some the byproducts of combustion stay with the oil. I change my oil every 3000 not because I believe the oil is worn out, but because of the other junk that is in it.

[Mark B]

While the lubrication properties of the oil might not be worn out at 3000 miles, the oil picks up contaminants, acids, & fuel. The contaminants can mostly be filtered out, but some the byproducts of combustion stay with the oil. I change my oil every 3000 not because I believe the oil is worn out, but because of the other junk that is in it.

Exactly My Thoughts

[wolfdogs]

we have the very lengthy, costly, oil durability study that was released a while back here in the office. its locked in my bosses office and he's on travel or i would give yall the name of it. it basicaly says people are changing thier oil too often.... but you still have to change it.

now... isnt it interesting that Ford says what they say.... yet... here in GSA Fleet, our oil change interval is 7500 for all passenger cars and light trucks, no matter who the manuf. is, except gm, and we use the oil minder light for them... Ford have given us grief over it..in fact, thier oil change interval for 2005 is 5 or 6k (i cant remember off the top of my head)... yet gm's system is letting some vehicles go 10k.... honda is at 10k........... so ..... go figure....

[loudRED94TA]

My neighbor is an amsoil dealer and he says to change it 1 time a year or 25000 miles but he says you just change your filter at 12500 or 6 months and then top it off. I cant say every oil is supposed to be used this way but thats what amsoil says.

[Christopherrr]

I couldn't let myself go over 4K without a change...just doesn't seem right. I'll stick to what I'm doing.

[Joe K. 99 Zeee!!]

Ken,

Is that the change interval the fleet is using for the filter as well?

[Dave-S]

Another interesting thing about Ford and Honda is they recommend 5W-20W oil in their cars. This is all very controversial but the consensus is this was done to fractionally improve the overall EPA ratings of the vehicles. If you do any kind of research on the matter, you will also find statements to the fact that the engine life for Hondas took a significant nosedive when they changed to the lighter weight oil. Take a look at this article http://www.smartsynthetics.com/artic..._and_honda.htm

Also look at this one. http://autorepair.about.com/library/faqs/bl804a.htm

I take all of this stuff with a grain of salt, but if you are keeping your car for a gazillion miles then change your oil every 3-5K miles. A car that doesn't see over 100K miles while in your posession, can probably follow manufacturers recommended change intervals.......and oh by the way.......don't use 5-20W oil at all!

[SSMOKEDU]

While I use Mobil 1 in the SS, I still can't get passed being "anal"
I still change it every 3K

[TraceZ]

I change my Mobil 1 every 5,000 miles.

I do have an idea as to why modern motors can go so long between changes and last longer in general. I think electronic port fuel injection is the biggest factor. here is an example:

With a carbed motor on the intake stroke the cylinder is filled with a mixture of air and fuel. This fuel washes the oil off the cylinder walls and gets in the crankcase contaminating the oil there as well. As the piston comes up for compression the rings experience heavy wear due to the fuel soaked cylinder walls lacking some lubrication. As a result the engine wears out more quickly and the oil gets contaminated faster.

With a port FI motor on the intake stroke the cylinder is filled with nothing but air. There is no fuel present to wash the oil from the cylinder walls so they stay well lubricated. Then the fuel is quickly injected near top dead center just before the spark ignites the mixture. It immediately burns and there is much less chance for the fuel to contaminate the oil.

[95TransAm]

I change my Mobil 1 every 5,000 miles.

I do have an idea as to why modern motors can go so long between changes and last longer in general. I think electronic port fuel injection is the biggest factor. here is an example:

With a carbed motor on the intake stroke the cylinder is filled with a mixture of air and fuel. This fuel washes the oil off the cylinder walls and gets in the crankcase contaminating the oil there as well. As the piston comes up for compression the rings experience heavy wear due to the fuel soaked cylinder walls lacking some lubrication. As a result the engine wears out more quickly and the oil gets contaminated faster.

With a port FI motor on the intake stroke the cylinder is filled with nothing but air. There is no fuel present to wash the oil from the cylinder walls so they stay well lubricated. Then the fuel is quickly injected near top dead center just before the spark ignites the mixture. It immediately burns and there is much less chance for the fuel to contaminate the oil.

That definitely makes sense. I'm ashamed at myself for not even thinking that....good call

None the less, I'll overkill it every 3k