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Went to my Mechanic for an oil/filter change last week. I waited for the 'oil life monitor' to be at 4%. My Mechanic said a lot of people in all kinds of cars and trucks are coming in when the oil life monitor is at 30% or more. There is a general impression that at, say 30%, the oil is only 30% as good as it was when new...he says this is not the case..30% just means the oil has 30% of good quality life left on it..basically good as new, except a bit broken down on the molecular level & a bit dirtier but otherwise still has excellent lubricating properties. He finds this a waste of money and bad for the environment and says it is perfectly safe to go until you get the DIC 82 code and even then you have about another 500mi of good oil left..particularly if it is synthetic oil. He suggests using a good quality GF-5 rated conventional oil as cost effective good & oil life right down to the DIC code 82 message. Nuff said..

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Keep in mind even just fairly recently GM has had to recalculate the oil life monitor in some models due to excessive timing chain wear . I see a lot of that problem at the dealer , sometimes several customers at once . The only way to know is to have a company like Blackstone test the oil . I change the original oil out at 500-1000 miles and even then there's obvious metal from the machining process . I change mine out at around 40% to be on the safe side . Years back the engineers that designed the system recommended changing at 50% . You would be surprised at what some of the engineers say that developed these systems . That's not to say changing the oil according to the maintenance computer says will do immediate harm but will probably be difference for those that keep their cars 200K miles . On my CR-Z everything is based on the computer , it might not say to change the CVT fluid till 30-40K miles or longer . However the engineer that designed car said it needs to done by 15K , it's a 10 grand mistake if the computer is wrong . The manufacturer is interested in getting past warranty and extended warranty claims and giving you low cost maintenance over a decent life span so it boils down to an owners comfort level and how long they plan on keeping the car . I see people do it both ways but I'm in the proactive camp . I base this on 30 plus years building and testing parts with a major manufacturer that supplied to the big 3 and I suspect not much has changed .

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Keep in mind even just fairly recently GM has had to recalculate the oil life monitor in some models due to excessive timing chain wear . That's not to say changing the oil according to the maintenance computer says will do immediate harm but will probably be difference for those that keep their cars 200K miles . The manufacturer is interested in getting past warranty and extended warranty claims and giving you low cost maintenance over a decent life span so it boils down to an owners comfort level and how long they plan on keeping the car . I see people do it both ways but I'm in the proactive camp . I base this on 30 plus years building and testing parts with a major manufacturer that supplied to the big 3 and I suspect not much has changed .

Thanx 'sparkfanatic'! Some very useful info that I was not aware of. Although I base my oil changes on the oil life indicator, I also combine that with common sense in the way that if the 'oil indicator' says 50% and I have driven, say, 5Kmi, I know that something is not right. Using quality GF-5~ 5w20 conventional oil, I expect an absolute max of 7,500 miles for the oil life, regardless of what the oil life indicator reads. I do find the indicator handy when you don't recall the last change mileage or are about to go on a long trip or drive a lot of short trips..even so there is usually a sticker or a retained invoice for the last change. I think, though, it can be very useful for those in colder climates making a lot of short trips that greatly shorten the oil life and cannot be determined by mileage only. The same oil, making a lot of short trips in colder climate may only be good for say 4Kmi where driving mostly long trips on the highway in warmer climates or an engine constantly at operating temp may yield much higher oil quality retention such as 7Kmi, or more with synthetic. As we all know, cold engine operation gives incomplete combustion and fouls the oil with carbon (dirty) giving a much shorter oil life. Personally, I find the oil life monitor on our Spark to be surprisingly accurate as I have done the math and for our driving habits 6 to 7,000 miles from 100% to code 82 on the DIC seems to be quite accurate considering this is a domestic type electronically computed gauge that basically works on engine temp, total rpm, load and speed.

When working as a pilot we relied on a variety of instruments...some mechanical and some electronic and even though they were all calibrated at regular intervals to the highest standards, we always used the 'rule of three', particularly when reading the 2+ fuel gauges and the altitude (AGL-ASL). Rule of three was that (1) always be prepared for a 7% error in fuel readings, (2) co-pilot/engineer did a by hand calculation of fuel considering factors such as distance, altitude and air density/humidity and (3), both Pilot and Co-Pilot had to agree. In 20+ yrs we only once found a critical gauge (Left wing fuel) giving a reading inconsistent with our math and to be safe we landed before our destination just to have that checked and fuel added (which was FAA SOP). Turned out the gauge was 100% accurate and our math 'somewhat' wrong due to not considering frequent altitude changes due to weather. Needless to say, my employer was less than pleased with added fuel costs by the 'non-contracted' fuel supplier at the chosen airport, xtra airport fees and xtra fuel consumption (Taxi & takeoff) and customer complaints, etc...

**OK...not all Spark related, so.....'Nuff said.... B)

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all my cars are low mileage, my feeling once a year oil changes is just not natural lol.. I usually do 50% or 6 months which ever comes first... speaking of which need to get the oil changed in the truck.. this is just me though.. and that the oil change is either free or $15 including an MPI it's worth the occasional look under the hood by a professional.

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all my cars are low mileage, my feeling once a year oil changes is just not natural lol.. I usually do 50% or 6 months which ever comes first... speaking of which need to get the oil changed in the truck.. this is just me though.. and that the oil change is either free or $15 including an MPI it's worth the occasional look under the hood by a professional.

I agree about once a year being a bit long, but if you are using synthetic oil (or even a good GF-5 conventional oil), 50% or 6 months is a bit over the top IMO. Having a mechanic look under the hood more frequently is always a good idea and your oil change frequency is, of course, not a bad thing except for the additional costs and the fact that it is not good for the environment, specially if everyone did that. The money saved by less frequent changes could be used to take your best girl to a good dinner when she recovers from he crash injuries...I do believe that now all oil change service places are required to send the used oil in for recycling where it is used for other products or oils as well as the lipstick & other cosmetics your girl uses...(I think)...& that's really 'Nuff said about that kinda stuff.

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My mechanic's son has a 2013 Spark. He changed his son's Spark oil (conventional GF-5 rated oil) at the DIC 82 mark...about 7,500+mi of pizza delivery. Mechanic decided to send the oil sample to be tested just to see how accurate those 'oil life monitoring' systems are on this model. Came back that the oil sample submitted still had about 1,500-2,000mi life left with virtually no metal deposits in the oil (good). He tells me he has sent out other samples for various cars with the monitoring system and most all come back with 300 to 2,000 miles of life left after an oil change is indicated by the monitor. Varies between makes and models. Some people come in for a change after almost 2 yrs with various high miles on the oil but still before the monitors 0% reading and the oil he has sent out for those cars all failed as less than 0-100 miles left due to breakdown of the oil in the 2year period...mostly because all engines get some fuel contamination over time.

Edited by Retired old Gearhead
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Im Concerned because my oil life monitor doesnt seem to be working--Im past due for oil change per mileage--any idea why my monitor is not working?--OnStar sez my oil life is at 10%--would have done oil change much sooner--was unemployed for a few months-=better now!!

Any Comments appreciated--Thanks--Mine is 2013--1.2LT

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I don't think you need to change the CVT fluid.  But, I guess it wouldn't harm it unless you totally use the wrong fluid.  I was thinking of adding a transmission cooler since she gets tracked on the weekends and I tow my small trailer during the week.  CVT's don't like heat, so I want to keep it as cool as possible.

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