Why Oil goes Bad

[greasemonkeyok]

"There are three primary causes that necessitate an oil change: degradation of the base oil, depletion of additives and contamination. Some of these conditions can be remediated, yet others cannot."

Good article at:
Why Oil Goes Bad

 

[John Morgan]

And yet you still have thousands of people, who will argue till their blue in the face, oil will last forever if you can keep it clean. Once the additive packages deplete heat builds. Excessive heat will degrade the base stock. Contaminates start accumulating almost immediately in conventional oils, leading to faster break down of the additive packages. Higher end oils have stronger additives to help reduce contaminates and heat resulting in longer drain intervals. It seems a fairly simple concept some will never accept. Thanks for your post, it keeps me going.

 

[beppington]

I don't dispute that oil goes bad, just not nearly as fast as Jiffy Lube (et al) would like us to believe.

 

[John Morgan]

Also reasonably accurate statement. Yes, lube places want to make a profit as well. However, what quality oil could you possibly get for $19.95. Lower quality oils like in most of those quick change places degrade pretty quick. There are many medium quality oils you can buy anywhere (Valvoline, Castrol, Quaker State, Etc....) that 3000 mile changes are a waste of money. Then you have several quality extended drain oils available that are higher priced per unit, but will save money overall. The quick change places offer other oils so they can up-sale, but they charge a lot for it.

 

[Runner]

Maybe I missed it, but I didn't see anything in the article that actually gave any indication of approximately how long oil (say, motor oil) can be expected to last before it is degraded to the point it's not doing it's job.

 

[two_bit_score]

Maybe I missed it, but I didn't see anything in the article that actually gave any indication of approximately how long oil (say, motor oil) can be expected to last before it is degraded to the point it's not doing it's job.

Doesn't that depend on how it's used and the service conditions?

 

[John Morgan]

Yes... There are many different factors that contribute including environment, mechanical stability, how the operator runs the equipment, service interval, etc. Since the OEM has no idea how the equipment will be operated, they establish recommendations based on minimum requirements for oils. If the oil can pass certain minimum standards it can last ex. 200hrs or 250hrs, whatever they determine. Therefore, they set their recommendation to prevent over extending the oil and causing damage. When you have extended drain lubricants you have to establish new drain intervals based on the mechanical stability of the oil through oil analysis. Don't let some sales guy or small distributor tell you their oil can do such and such without backing it up with oil analysis and incremental increases to insure machanical safety.

 

[Diamondpilot]

This may all be true but oil and a filer is so cheap, why not? I use medium grade motor oils in all my stuff with the exception of my Nissan Titan where I use higher grade stuff. Yes, I could go longer than 5,000 miles on vehicles or every year on my equipment and boats but why? Say I save $40 per year per vehicle what am I gaining? You can not replace the valve cover gaskets for that. I would rather have the piece of mind knowing its fresh oil and ready to go.

I know guys who do oil monitoring on things that use 4-6qts of oil. They change Just the filter once every 100 hours or so. Seems stupid to me to pay $30 to see if the oil is good, $5 for a new filter, and $3 for a qt of oil to top it off when they could just change it for less or the same $$$$

Chris

 

[John Morgan]

Hello Chris,

That is what works for you and many people who have a couple of cars and 1 or 2 other pieces. You are right, it may not be worth the $40/car savings. It is worth that to others. If you have 6 pieces of equipment that $240/year. How many people do you know who will drive 5 miles out of their way to save .02 /gallon on gasoline. If you noticed in all my postings on this string, I didn't talk bad about any oil, they all do what they are designed to do. Some are designed to do more than others. On your Nissan Titan, did you notice an increased fuel efficiency when you switched it to the higher grade oil? Most people typically will. Mine averaged 5% between my two cars when I switched them. As much as I drive, 5% fuel savings, extended drain interval, no filter change in between and reduced repair bills makes my oil pay for itself. My oil analysis kit is only $10.50, so it is a lot more savings to me than $40/car/year.

 

[Bird]

For many, many years (until last year, in fact) I changed oil & filter in my vehicles every 3k miles. Every dealer I knew of in the Dallas area said they considered our heat, air polution, stop and go traffic, etc. to be "severe service", but last year, my Ford dealer started recommending 5k mile intervals instead. My last oil & filter change cost $29.43 total at the dealer. I've gone 4k miles each of the last 2 changes, but old habits are hard to break.:laughing: