BodybyFisher Posted December 9, 2010 Report Share Posted December 9, 2010 UPDATE: I received the CHANGE ENGINE OIL message this morning! That is after driving for a day at 0%..... The oil is going to get changed this evening. That's a good news. Nevertheless, if the message is displayed at or below %0, the OLM alert is useless. I would disconnect the battery (the both cables for the heck of it) to reset the computers (if there is something to be reset), and keep a log of oil life versus mileage and date for reference and analysis. I would not say its useless, the manual states you have 200 miles to get it changed, its just that it does not come on at 10% remaining.. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
KHE Posted December 9, 2010 Author Report Share Posted December 9, 2010 There is a considerable factor of safety in the oil life - I am not concerned that it was at 0% for a couple of days. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
JimD Posted December 9, 2010 Report Share Posted December 9, 2010 There is a considerable factor of safety in the oil life - I am not concerned that it was at 0% for a couple of days. I didn't speak up sooner Kevin, because I knew the message would appear and I suspected you would wait for it Here is part of what my '04 DeVille Owners Manual has to say on pg 5-18: When to Change Engine Oil (GM Oil Life System) Your vehicle has a computer system that lets you know when to change the engine oil and filter. This is based on engine revolutions and engine temperature, and not on mileage. Based on driving conditions, the mileage at which an oil change will be indicated can vary considerably. For the oil life system to work properly, you must reset the system every time the oil is changed. When the system has calculated that oil life has been diminished, it will indicate that an oil change is necessary. A CHANGE ENGINE OIL message in the Driver Information Center (DIC) will come on. Change your oil as soon as possible within the next two times you stop for fuel. It is possible that, if you are driving under the best conditions, the oil life system may not indicate that an oil change is necessary for over a year. However, your engine oil and filter must be changed at least once a year and at this time the system must be reset.... Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 9, 2010 Report Share Posted December 9, 2010 That is some patience, considering that it read 0% for a DAY before it came on, but then again Kevin is a very patient person. That is not logical that is did NOT come on at 0%, patience or no patience At 0% you would have to assume that the requisite number of engine revolutions HAD taken place OR, it wouldn't have read 0% Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Cadillac Jim Posted December 9, 2010 Report Share Posted December 9, 2010 I think that the display must round down the actual number computed by the OLM. If so, the extra day is that last 1%, or, if it instead rounds up or down to the nearest number, the last 0.5% of the oil life. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
adallak Posted December 9, 2010 Report Share Posted December 9, 2010 UPDATE: I received the CHANGE ENGINE OIL message this morning! That is after driving for a day at 0%..... The oil is going to get changed this evening. That's a good news. Nevertheless, if the message is displayed at or below %0, the OLM alert is useless. I would disconnect the battery (the both cables for the heck of it) to reset the computers (if there is something to be reset), and keep a log of oil life versus mileage and date for reference and analysis. I would not say its useless, the manual states you have 200 miles to get it changed, its just that it does not come on at 10% remaining.. I agree, but I just would not trust OLM if the message does not appear when it is supposed to do (10%). I would keep an eye on it. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 9, 2010 Report Share Posted December 9, 2010 I'd be thrilled if it came on AT 0%, not a day later... how do they explain that in a manual....oh it might come on?, I realize its inconsequential, but, if SHOULD come on at 0%, not a day later. Its ok to change, from 10% to 0%, but, it MUST come on at 0%, not when it feels like it Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
JimD Posted December 9, 2010 Report Share Posted December 9, 2010 Hold on folks. This ant hill is becoming a mountain. Kevin's comments relate to a 2005 engine. The DIC display does not include decimals. So the PCM calculation that yields a 0.6% engine oil life value will be presented as 1% ENGINE OIL LIFE. Likewise, a PCM calculation that returns a value of 0.4% oil life will be presented as 0% ENGINE OIL LIFE. The CHANGE ENGINE OIL message is not displayed until the calculated value counts down to 0.0%. At some point between 2000 and (Kevin's) 2005 model, Cadillac engineers decided to display the CHANGE ENGINE OIL message at 0% rather than 10%. A vote of confidence in the accuracy/reliabilty of OLM algorithm, right? Several times I have driven my old reliable '98 engine well beyond 0% ENGINE OIL LIFE without guilt or placing my engine at risk (and I'm north of 200,000 miles). I have trouble understanding the logic of trusting the OLM display down to 50% or 40%, but not trusting the OLM down to 0%. My contribution to building this mountain Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 10, 2010 Report Share Posted December 10, 2010 Well that makes sense then, now they need to change their display to 0.0 Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
adallak Posted December 10, 2010 Report Share Posted December 10, 2010 The next generation DIC message will be "Have you changed oil 2000 miles ago?" The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ranger Posted December 10, 2010 Report Share Posted December 10, 2010 From the Guru himself. "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." Oil Life Monitor (OLM).doc Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 10, 2010 Report Share Posted December 10, 2010 The next generation DIC message will be "Have you changed oil 2000 miles ago?" It will be, WHAATTT, you didnt call up your OIL LIFE MONITOR, what do we need to do everything for you?, please visit your nearest service department for new bearings, Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
adallak Posted December 10, 2010 Report Share Posted December 10, 2010 The next generation DIC message will be "Have you changed oil 2000 miles ago?" It will be, WHAATTT, you didnt call up your OIL LIFE MONITOR, what do we need to do everything for you?, please visit your nearest service department for new bearings, :D The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
KHE Posted December 10, 2010 Author Report Share Posted December 10, 2010 JimD, The text from your 2004 manual is identical to the 2005 manual. I was not concerned about the oil life being 0% for a day as I know there is a factor of safety in the algorithim. I would have thought the CHANGE ENGINE OIL message would have appeared at the next ignition cycle after the oil life dropped to zero though. At any rate, the oil life is now 100% - I changed the oil and filter yesterday evening. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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