Syntyhetic vs. Conventional Motor Oil

Discussion in 'Maintenance & Upkeep' started by arinmybackpocket, Aug 19, 2012.

  1. OK...I know that the topic of motor oil and what's best has been nearly beat to death but in my search I didn't find the exact info I was looking for so I thought I'd create one more thread on the subject.

    I have a few questions:

    - Standard oil life for conventional oil is 3k miles. What's th standard for synthetic?

    - Does my oil life indicator on my newer chevy truck (2007 Silverado) actually detect contaminates in my oil or does it dwindle down over a 3k mile span? The owner's manual gives the impression that there is a mechanism that measures constiminates rather than giving a percentage based on miles driven.

    - I've had Royal Purple synthetic motor oil hyped to me alonf with the new Green Earth Technologies (GET) Advanced Synthetic line. Anyone have any feedback on either? I like the idea of buying any oil made from resources here in the USA like with GET.

    - Can I really see improved fuel economy from going to synthetic from conventional?

    Thanks in advance for your responses. Any other thoughts on conventional vs. Synthetic motor oils are welcome as well. Thanks guys.
  2. See my comments in red above.
  3. dpeter

    dpeter Epic Member 5+ Years 500 Posts

    I default to the oil life indicator for my use. It activates about every 5,000 to 6,500 miles and as it happens is about 3 months or less in time and it is almost a quart low. I choose not to second guess the engineers at GM. They know more about their products than I do.
  4. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    The oil life meter takes in factors about engine operations like given rpms, miles driven, idle time, operating temperature, and others to determine when the oil needs to be changed, normally it wont activate oil change time at the same miles driven every time.

    For example on my wifes HHR it normally goes on close to 7000 miles, a few years ago she couldnt drive for a few months so I was using her car, I'm a little more aggressive driver than her and the monitor signaled oil change time at 5500 miles. When we took her car on a trip we drove almost 8000 before it signaled oil change time.

    The oil life monitor system doesnt care what type oil your using, conventional or synthetic, it has its parameters and when their met it determines it's time to change the oil.

    With that in mind I would still recommend changing oil at the prescribed time even if you change to synthetic, at a certain point your oil becomes diluted with unburnt fuel and this starts a breakdown of the oil, unless you have the technology and factors to continuously and accurately check your oils material condition you wont know when your oil has reached the point where its degrading and causing more damage than is acceptable.

    Also if you read your warranty they dont care if your using synthetic either, oil change time is oil change time and if you cant prove they were done within a reasonable amount of time on schedule any repair bills attributable to that failure are yours.

    Fuel mileage with synthetic oils wont be an instantaneous jump, a gain of a few miles a tank full would be the most you should expect, this isnt a magic elixir that will suddenly make your vehicle act like a hybrid.

    The largest gain with synthetics is slowing the material degradation inside the engine.
  5. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    I agree with all of the above...........................synthetic oil, and using the oil change indicator system, is simply the best thing you can do for your engine.
  6. Big_Mike

    Big_Mike Member 100 Posts

    I'll try not to repeat what has been mentioned above... One thing to note is that some people (me included) go by the rule of thumb to change oil every 3000 miles. The oil never truly stops lubricating It just gets dirty and when you change it, so you are draining out contaminants that result from using your engine. Think of oil as the "blood" or "life" of your engine. Synthetic oil is more expensive, but may be worth it depending on the vehicle and its intended use. Personally, I wouldn't run it unless the manufacturer recommended it or if you were using the engine for something like racing or other high load conditions (tractor pulls, possibly extensive off-roading, for example). As for the light that comes on telling you to change it, I believe those are put installed for the common person who doesn't know much about their vehicle (or in some cases, doesn't care).
    So in other words, it's for the average person who never pops the hood to inspect his/her vehicle. Forgive me for this tangent, but take this for example, ever notice how common production car engine bays have a lot of black components in them? Well black doesn't show filth from lack of cleaning, which is why manufacturers do that and why usually only chrome (among other materials/finishes) engine parts are seen on high end vehicles (along with cost of materials as well).
    I don't know if there is an improvement in fuel economy. I've never heard about that. So check out this link:
    However, if you want to do more homework about engine oil check out this link:
    I didn't read all of it, but through what I did, it seemed somewhat credible. And remember (even though it sounds like you already do this) you can always refer to your owner's manual or talk to a trusted mechanic. Good luck and I hope you get the answers you are searching for. And I am glad to hear you are a supporter of American made products :) God Bless the USA!!!
  7. dpeter

    dpeter Epic Member 5+ Years 500 Posts

    " As for the light that comes on telling you to change it, I believe those are put installed for the common person who doesn't know much about their vehicle (or in some cases, doesn't care).
    So in other words, it's for the average person who never pops the hood to inspect his/her vehicle."
    Big_Mike, that hurts.
  8. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I use royal purple or Mobile one in my trucks. I change it when the light tells me to. If I pull the boat alot and it is hot out the light might come on after only 4,000 miles. If I drive light it may take 6,000
  9. Skippy

    Skippy Member 2 Years 100 Posts

    I had to laugh out loud on this one! I found it funny that you're stating that the light is for people who don't know about their vehicle, and yet you personally state that you change your oil at 3000 miles without a reason other than "Rule of thumb." *grin* (come on... that's funny!)

    There are much more scientific methods for people who know about their vehicles. And one of them is the calculated indicator light. In fact, a better "rule of thumb" is to actually follow the calculated recommendation by the engine's computer. Changing more frequently is wasteful. Here's why:

    Oil life is determined not by miles, but by actual degredation and total contaminants. Because of this, very few engine owner's manuals will recommend oil changes at 3000 miles (though every oil change shop will!), because the engine oil is still fine at that point. At the low end interval, most manuals under "Severe" conditions will recommend changes at 3500 miles, and under "Normal conditions" will recommend at 7000+ miles (totally dependent on the engine of course). The actual lifespan of your oil is STILL beyond that interval cycle. The problem is how to determine if you've driven "Severe" or "Normal" or somewhere between. It's guesswork, unless you understand the mechanics of how you drive. Fortunately, the engineers at the manufacturers have helped us with that with on-board computer calculations of driving conditions. They've done a GREAT job of helping consumers reduce unnecessary oil changes (saving money, and the environment). The calculation is a far more accurate means of oil change interval than other "rules of thumb." Changing oil too early won't hurt, but it also won't help either. All that being said, how do we determine when an oil change should occur?

    In short, unless you have better information (See below), if your vehicle is so equipped, use the oil change indicator light to determine when the oil should be swapped out (along with the filter, of course). Changing significantly earlier may make you feel better, but isn't likely to protect your engine any better than oil that was already protecting your engine. Basically, it's just tossing oil into the recycle bin, and throwing money out the window.

    Really, the only way to do an accurate accounting of your oil condition is to have it lab analyzed.

    That being said, and you'd like to be convinced that 3000 is the correct time to change (or any other time for that matter), if you really want to see if your engine oil needs to be changed at 3000 miles, you can have an analysis run (this will cost you about $25, but will give you a scientific basis for understanding YOUR engine). The cost of analysis is about the same as an oil change ($25). Fortunately, if you're really changing your oil every 3000 miles, this singular $25 investment is likely to pay dividends in all future oil change frequencies by helping you understand at what point you more realistically should be changing your oil. Remember that if you're changing your oil every 3K and you can really run to 6K or beyond, that's roughly half the cost of oil changes (you'll quickly get your $25 investment back). Not only that a great oil analysis will help you understand other things that are going on in your engine.

    Blackstone labs is who I use. They will send you a bottle, instructions and a return envelope. In return, you get a report back that shows you all kinds of information about the health of your engine, and specifically, about the oil and it's ability to protect. You'll quickly find out if you're replacing oil too soon, not soon enough, or just about right. They'll even give you instructions on how to read the report. Primarily, the TBN value (Total Base Number) is used to determine the overall ability of oil to do it's job in your engine. As long as the TBN is high enough, your oil is still functioning properly, and changing it out isn't going to make much difference.

    Here's a link to see how oil analysis works:

    In summary, in all the studies I've read, the oil change calculator (and associated indicator light) do a great job indicating when the oil is approaching it's lifespan limit (but actually before it). The calculation is based on conventional oil (which breaks down faster) and synthetics will go even longer. Regardless, both oils are still doing their job at the oil light indicator, and you'll find that by following the light, instead of the "rule of thumb" you'll save a few bucks and will still have great protection for your engine. Recommending earlier intervals is simply akin to buying into the fear, and evidence of lack of understanding of how oil really functions. Be educated, be thrifty, be more green. Win win win. :)


  10. dpeter

    dpeter Epic Member 5+ Years 500 Posts

    Skippy is right on:great:.

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