Change Oil Light

[LordLang]

I have 10,000 miles on my H3. I have changed the oil twice, once at 4k and another at 8500. Neither of these times the change oil light came on, but i had it changed anyways. Now after only 1500 miles since the last change the change oil light has come on. I checked the oil and it reads full, as well as looks very clean. Any ideas on why this would happen? does it really need changed or do i just need to reset the light? and if so, how do i do that? thanks for the help!

[deserth3]

Sounds to me like someone either didn't reset the oil light or the reset didn't take.

Agreed, sounds like it was not reset at last change? Has anybody actually seen how many miles before change oil light comes on (assuming it was reset properly)?

S.

[Scouts Out]

I changed mine at 3500 miles and I was determined to wait until the computer told me to change it again, well at 9500 I blinked and changed it again even though the computer said I had 65% oil life remaining. Not sure what the computer uses to determine when to change the oil but I am not sure I trust it.

[LordLang]

OK, so does anybody have any idea how to reset it? how did you find the oil life left?

[HummBebe]

Instructions are in the owners manual, chapter 5

[deserth3]

This is what the manual says.

How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
your engine oil and filter based on vehicle use. Anytime
your oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change your oil prior to a CHANGE OIL
message being turned on, reset the system.
To reset the Engine Oil Life system, do the following:
1. With the engine off, turn the ignition to ON.
2. Press and release the stem in the lower center of
the instrument cluster until the OIL LIFE message
is displayed.
3. Once the alternating OIL LIFE and RESET
messages appear, press and hold the stem until
several beeps sound. This confirms that the oil life
system has been reset.
4. Turn the key to LOCK.
If the CHANGE OIL message comes back on when you
start your vehicle, the engine oil life system has not
reset. Repeat the procedure. See DIC Warnings
and Messages on page 3-44.

[LordLang]

That worked, thanks a ton. Sorry im so lazy and didnt just look in the manual myself!

[Huck BB62]

Originally Posted by Scouts Out

I changed mine at 3500 miles and I was determined to wait until the computer told me to change it again, well at 9500 I blinked and changed it again even though the computer said I had 65% oil life remaining. Not sure what the computer uses to determine when to change the oil but I am not sure I trust it.

Trust it. Changing oil at 3000 miles is a waste of money, and of oil (ahhhh precious oil) Today's fuel injected engines don't crap the oil up like the old carbed/choked engines. I can't find it right now but I've seen tests confirming that GM's oil change intervals are still conservative. If have any fears, run synthetic, get better oil AND the piece of mind. The computer's going off of how you drive. Trust it.

I'm leaning towards the longer intervals as guided by the GM oil monitoring system. 7500 miles since my last change and no "oil change" light so far.


S.

[Scouts Out]

Being in the Military I am a big fan or the AOAP (Army Oil analysis Program). They run a sample and can tell you the life left in the oil, the metal particales in the oil to know what parts are wearing and about 50 other things they can do.

[f5fstop]

Originally Posted by Huck BB62

Trust it. Changing oil at 3000 miles is a waste of money, and of oil (ahhhh precious oil) Today's fuel injected engines don't crap the oil up like the old carbed/choked engines. I can't find it right now but I've seen tests confirming that GM's oil change intervals are still conservative. If have any fears, run synthetic, get better oil AND the piece of mind. The computer's going off of how you drive. Trust it.

AMEN

It does side on the conservative side. It calculates the engine oil life dependent upon engine startup temps, engine run time, speed, engine temps, air intake temps, etc.
It does assume you are using the specified oil that meets GM specifications, it also assumes you are running a paper filter. (Foam filters allow more dirt into the system.)
I have personally verified the system is conservative with my Vette, by having oil samples run by a firm called Blackstones in Indiana. Even with 10 percent left, the analysis indicated the oil was good for thousands of miles of further use.
I don't believe there is a way to check the oil life without a Tech 2, or via the Onstar monthly email>

[Huck BB62]

If this writeup by a member on another forum doesn't convince you, well, go ahead and waste your time, money, and our oil:

One thing I can touch on and clear up.....the GM oil life monitor operation and my statement that ZDP (or ZDDP as you tend to call it here...most of the API literature just sticks to ZDP so I tend to use that) depletion is the basis for oil deterioration.

My spelling is poor but ZDP stands for zinc dialkyldithiophosphate which , as it sounds, is an anti-wear compound comprised of zinc and phosphorus.

ZDP is dispersed in the oil so as to be at a potential wear site if a surface asperity happens to break thru the oil film thickness causing the dreaded metal-to-metal contact. A molecule of ZDP must be present at that moment to prevent microwelding at the contact site which will cause material transfer, scuffing, scoring, wear and catostrophic failure. The concentration of ZDP in the oil will determine if there is ZDP present to work it's magic. The greater the concentration...the more likely a molecule of ZDP will be there...and vice versa.

By nature, ZDP is sacrifical. As ZDP is "used up" at a wear site to prevent micorwelding the concentration of ZDP decreases.... So...if you measure the ZDP concentration in engine oil in a running engine it will decrease at linear rate based on engine revolutions. Any given engine has a certain number of high potential wear areas where metal-to-metal contact could occur due to reduced film thickness and/or surface asperities....areas such as rubbing element cam followers, distributor gears, rocker arm pivots, push rod tips, etc...... The more of these areas the more ZDP depletion. The more often these features come in contact the greater the ZDP depletion. That is why, generally speaking, ZDP concentration in the oil, for any given engine, will decrease at a fairly linear rate when plotted versus cummulative engine revolutions. The more times it turns the more contact the more chance for wear the greater the depletion. This is as much of a fact as I could quote ever and is really not speculation or anything. It is proven beyond a shadow of a doubt in many studies. That is why it is ONE of the basis for determining oil life remaining and why it is THE basic premis of the GM oil life algorithm. It is only ONE of the things that determines oil life...but it is the one thing that can be tied to engine operation in a linear fashion and estimated very accurately by accumulating engine revolutions via a counter.

The GM engine oil life monitor counts engine revolutions and accumulates the number for the basis of the oil life calculation. It then adds deterioration factors for operating temperature, start up temperature, soak times, ambient, coolant temperature, etc... There are a LOT of factors that "adjust" or affect the slope of the deterioration but the fundamental deterioration is traced back to the ZDP depletion that is inescapable with engine revolutions. The specific rate of ZDP depletion is readily measurable for any given engine so that is the fundamental item that is first calibrated for the oil life algorithm to tailor it specifically to that engine.

You would obviously like to get the oil out of the engine before the ZDP concentration gets so low that it is ineffective at being at the right place at the right time and preventing engine wear so that becomes the long term limit on oil life for that application.

The other things that determine oil life such a acid build up, oxidation, petane insuluables such as silicon from dust/dirt, carbon or soot build up from the EGR in blowby, water contamination, fuel contamination, etc.... are all modeled by the multipliers or deterioration factors that "adjust" the immediate slope of the line defined by the engine revolution counter as those items can be modeled in other ways and accounted for in the immediate slope of the ZDP depletion line.

The algorithm was developed over the course of many years by several lubrication experts at GM Fuels and Lubes, spearheaded by Doctor Shirley Schwartz who holds the patents (with GM) for the algorithm and the oil life montitor. I had the luck of working directly with Dr. Schwartz when the idea of the oil life monitor first progressed from the theoretical/lab stage to real world testing/development/validation. There were fleets of cars operated under all conditions that deteriorate the oil life for any and every reason and , thru oil sampling and detailed analysis of the oil condition, the algorithm was developed, fine tuned and validated to be the most accurate way invented yet to recommend an oil change interval by. As just one example, I have seen cars driven side-by-side on trips, one towing a trailer and one not, for instance, to prove the effectiveness of the oil life monitor in deteriorating the oil at a faster rate just because of the higher load, higher average RPM, higher temps, etc...and it works flawlessly.

The oil life monitor is so effective because: it is customized for that specific vehicle/engine, it takes everything into account that deteriorates the oil, it is ALWAYS working so as to take into account THAT INDIVIDUALS driving schedule, and it tailors the oil change to that schedule and predicts, on an ongoing basis, the oil life remaining so that that specific individual can plan an oil change accordingly. No other system can do this that effectively.

One thing is that I know personally from years of testing and thousands of oil analysis that the oil life algorithm works. There is simply no argument to the contrary. If you don't believe me, fine, but, trust me, it works. It is accurate because it has been calibrated for each specific engine it is installed on and there is considerable testing and validation of the oil life monitor on that specific application. NOt something that oil companies or Amsoil do. They generalize....the oil life monitor is very specific for that application.

Oil condition sensors in some BMW and Mercedes products are useful, also. They have their limitations, though, as they can be blind to some contaminates and can, themselves, be contaminated by certain markers or constituents of certain engine oils. Oil condition sensors can only react to the specific oil at that moment and they add complexity, cost and another potential item to fail. One other beauty of the GM oil life monitor is that it is all software and does not add any mechanical complexity, mass, wiring or potential failure mechanism.

There is considerable safety factor in the GM oil life monitor. Typically, I would say, there is a 2:1 safety factor in the slope of the ZDP depletion curve....in other words, zero percent oil life per the ZDP depletion is not zero ZDP but twice the concentration of ZDP considered critical for THAT engine to operate under all conditions reliably with no wear. This is always a subject of discussion as to just how low do you want the ZDP to get before the oil is "worn out" if this is the deciding factor for oil life. We would tend to be on the conservative side. If the oil life is counting down on a slope that would recommend a 10K change interval then there is probably 20K oil life before the ZDP is catostrophically depleted....not that you would want to go there...but reason why many people are successful in running those change intervals.

Please...NOT ALL ENGINES ARE THE SAME. The example above is an excellent practical justification of why you would want to add EOS and change the 15W40 Delvac in the muscle car at 3000 miles max and yet can run the Northstar to 12500 easily on conventional oil. You must treat each engine and situation differently and what applies to one does not retroactively apply to others. This is where Amsoil falls short in my book by proposing long change intervals in most everything if you use their oil. It just doesn't work that way. You can run the Amsoil to 12500 with no concerns whatsoever in the late model Northstar because even the oil life monitor tells you that for conventional oil off the shelf. Would I do that to the 502 in my 66 Chevelle...NO WAY. Amsoil says I can though. Wrong.


There are entire SAE papers written on the GM oil life monitor and one could write a book on it so it is hard to touch on all aspects of it in a single post. Hopefully we hit the high spots. Realize that a GREAT deal of time, work and energy went into developing the oil life monitor and it has received acclaim from engineering organizations, petroleum organizations, environmental groups all across the board. It is not some widget invented in a week and tacked onto the car.

[Wisha Haddan H3]

Originally Posted by Huck BB62

If this writeup by a member on another forum doesn't convince you, well, go ahead and waste your time, money, and our oil ...

Wow, thanks for the writeup and info. Very cool.

[usetosellhummer]

wow some serious Dr. Z stuff, still not sold, every 3-4 k as the old man told me too.

[Huck BB62]

Originally Posted by usetosellhummer

wow some serious Dr. Z stuff, still not sold, every 3-4 k as the old man told me too.

Can I ask why? I'm just curious. Testing has proven the oil-monitor conservative. Newer engines just don't mess up your oil. It is your money, and I respect the desire to take the very best care of your engine, it's just that this is a pretty obvious way to save time, money, and oil. You engine will be fine (probably outlast the rest of the vehicle!)

[HummerNewbie]

I get mine changed every 3K but that's because I get free service for the first 36K miles

[dеiтайожни]

Originally Posted by HummerNewbie

I get mine changed every 3K but that's because I get free service for the first 36K miles

x2, plus I like to waste oil, it's my part of developing an interesting future and push for alternative fuels.

[HummerNewbie]

Originally Posted by dеiтайожни

x2, plus I like to waste oil,...

Those of us in the business would like to thank you for your help

[dеiтайожни]

Originally Posted by HummerNewbie

Those of us in the business would like to thank you for your help

Oh no...THANK YOU.