cadillacjeff7777 Posted June 10, 2011 Report Share Posted June 10, 2011 Typically I have ignored the 3,000 mile mark for oil changes and let the car tell me when to change the oil but I am getting nervous on this one. It has been about 8,000 miles since it's oil change when I bought the car but the oil life indicator says that it is at 65% oil life. EDIT: Preform = Perform :/ 2008 DTS Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 10, 2011 Report Share Posted June 10, 2011 I fixed perform for you You should have an oil life monitor on your Cadillac. This is not simply a message that is 'timed', the oil life monitor is a sophistocated monitor using an advanced algorithm to monitor, a whole host of engine parameters along with trip distance. If you recall the manual used to say change your oil every 3000 for short local trips and 7000 for long trip highway style of driving. Who could ever determine that? The oil life monitor takes the guessing out of changing your oil. I dont have time now, but later I will post an excellent post by the guru on the OLM, its outstanding and it will give you good confidence in the OLM... Mike 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...
Texas Jim Posted June 10, 2011 Report Share Posted June 10, 2011 This is just ME... but I change mine when it gets to around 7,500 / 8,000 miles or 35 / 40 percent. I can't make myself wait any longer... :) Which it is at now. I will have it changed in the next few days. Most people go by the OLM, but it says in the manual, that it could go as much as 12,500 miles or one year between changes. I am too old school to wait that long.. Link to comment Share on other sites More sharing options...
cadillacjeff7777 Posted June 10, 2011 Author Report Share Posted June 10, 2011 Wow. I can't imagine going that long. Is synthetic required? I guess that I could dig it if it is synthetic. About 2K miles were highway. We took it up to Michigan and back a few weeks ago. 2008 DTS Link to comment Share on other sites More sharing options...
cadillacjeff7777 Posted June 10, 2011 Author Report Share Posted June 10, 2011 I fixed perform for you You should have an oil life monitor on your Cadillac. This is not simply a message that is 'timed', the oil life monitor is a sophistocated monitor using an advanced algorithm to monitor, a whole host of engine parameters along with trip distance. If you recall the manual used to say change your oil every 3000 for short local trips and 7000 for long trip highway style of driving. Who could ever determine that? The oil life monitor takes the guessing out of changing your oil. I dont have time now, but later I will post an excellent post by the guru on the OLM, its outstanding and it will give you good confidence in the OLM... Mike Thanks for fixing perform. Fingers just get going to fast here. On my old 93 and 95 Sevilles, the OLM would come on at about 6500-7000 miles with my driving which was mostly 55mph roads in the country side of west Michigan. I never looked in the manual to see what GM recommended for oil change intervals. I now live in Tulsa and drive mostly city driving. 12,500 miles on an oil change is unimaginable. I recall that the 3000 mile interval was from the old carbureted days and was no longer accurate as the modern fuel injection is much more accurate for fuel delivery hence lessening the blow by that would contaminate the oil. I want to say though that I remember hearing at one point that the oil filters themselves were not good past 6000 miles. I guess that I am real curious now to know the type of oil and filter to use if they are expecting you to go up to 12,500 miles on it. 2008 DTS Link to comment Share on other sites More sharing options...
Texas Jim Posted June 10, 2011 Report Share Posted June 10, 2011 If you raise the hood and look at your oil filler cap... I think it say "MOBIL 1" on it...which means that you should only use synthetic oil in it. But of course, the synthetic of your choice should be fine also... it don't have to be Mobil 1. I use synthetic, but still change it at around 7,500 to 8,000. More often if I drive it really hard. Oil is a lot cheaper than an engine... :) Link to comment Share on other sites More sharing options...
cadillacjeff7777 Posted June 10, 2011 Author Report Share Posted June 10, 2011 If you raise the hood and look at your oil filler cap... I think it say "MOBIL 1" on it...which means that you should only use synthetic oil in it. But of course, the synthetic of your choice should be fine also... it don't have to be Mobil 1. I use synthetic, but still change it at around 7,500 to 8,000. More often if I drive it really hard. Oil is a lot cheaper than an engine... :) I saw the oil cap before and never thought much about it. Didn't investigate what Mobil 1 was. 2008 DTS Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 10, 2011 Report Share Posted June 10, 2011 What is nice is that your engine has been designed and the OLM calibrated for the reduced zinc the oils today have. It would be nice if we had a GM rep here confirm that the OLM has in deed been recalibrated. The OLM depends highly on zinc depletion in its algorithm, I love this article here is EVERYTHING you wanted to know about the OLM, by theGURU... Please understand that this may be confusing as I have copied MANY ofhis OLM posts from different threads! He is THE MAN...Mike *************************************************************************** One thing I can touch on and clear up.....the GM oil life monitor operationand my statement that ZDP (or ZDDP as you tend to call it here...most of theAPI literature just sticks to ZDP so I tend to use that) depletion is the basisfor oil deterioration. My spelling is poor but ZDP stands for zinc dialkyldithiophosphate which , asit 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 surfaceasperity happens to break thru the oil film thickness causing the dreadedmetal-to-metal contact. A molecule of ZDP must be present at that moment toprevent microwelding at the contact site which will cause material transfer,scuffing, scoring, wear and catostrophic failure. The concentration of ZDP inthe oil will determine if there is ZDP present to work it's magic. The greaterthe concentration...the more likely a molecule of ZDP will be there...and viceversa. By nature, ZDP is sacrifical. As ZDP is "used up" at a wear site toprevent micorwelding the concentration of ZDP decreases.... So...if you measurethe ZDP concentration in engine oil in a running engine it will decrease atlinear rate based on engine revolutions. Any given engine has a certain numberof high potential wear areas where metal-to-metal contact could occur due toreduced film thickness and/or surface asperities....areas such as rubbingelement cam followers, distributor gears, rocker arm pivots, push rod tips,etc...... The more of these areas the more ZDP depletion. The more often thesefeatures come in contact the greater the ZDP depletion. That is why, generallyspeaking, ZDP concentration in the oil, for any given engine, will decrease ata fairly linear rate when plotted versus cummulative engine revolutions. Themore times it turns the more contact the more chance for wear the greater thedepletion. This is as much of a fact as I could quote ever and is really notspeculation 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 whyit is THE basic premis of the GM oil life algorithm. Itis only ONE of the things that determines oil life...but it is the one thingthat can be tied to engine operation in a linear fashion and estimated veryaccurately by accumulating engine revolutions via a counter. The GM engine oil life monitor counts engine revolutions and accumulates thenumber for the basis of the oil life calculation. It then adds deteriorationfactors for operating temperature, start up temperature, soak times, ambient,coolant temperature, etc... There are a LOT offactors that "adjust" or affect the slope of the deterioration butthe fundamental deterioration is traced back to the ZDP depletion that isinescapable with engine revolutions. The specific rate of ZDP depletion isreadily measurable for any given engine so that is the fundamental item that isfirst calibrated for the oil life algorithm totailor it specifically to that engine. You would obviously like to get the oil out of the engine before the ZDPconcentration gets so low that it is ineffective at being at the right place atthe right time and preventing engine wear so that becomes the long term limiton 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 fromthe EGR in blowby, water contamination, fuel contamination, etc.... are allmodeled by the multipliers or deterioration factors that "adjust" theimmediate slope of the line defined by the engine revolution counter as thoseitems can be modeled in other ways and accounted for in the immediate slope ofthe ZDP depletion line. The algorithm wasdeveloped over the course of many years by several lubrication experts at GMFuels and Lubes, spearheaded by Doctor Shirley Schwartz who holds the patents(with GM) for the algorithm andthe oil life montitor. I had the luck of working directly with Dr. Schwartz whenthe idea of the oil life monitor first progressed from the theoretical/labstage to real world testing/development/validation. There were fleets of carsoperated under all conditions that deteriorate the oil life for any and everyreason and , thru oil sampling and detailed analysis of the oil condition, the algorithm wasdeveloped, fine tuned and validated to be the most accurate way invented yet torecommend an oil change interval by. As just one example, I have seen carsdriven 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 ata faster rate just because of the higher load, higher average RPM, highertemps, etc...and it works flawlessly. The oil life monitor is so effective because: it is customized for thatspecific vehicle/engine, it takes everything into account that deteriorates theoil, it is ALWAYS working so as to take into account THAT INDIVIDUALS drivingschedule, and it tailors the oil change to that schedule and predicts, on anongoing basis, the oil life remaining so that that specific individual can planan 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 oilanalysis that the oil life algorithmworks. 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 calibratedfor each specific engine it is installed on and there is considerable testingand validation of the oil life monitor on that specific application. NOtsomething that oil companies or Amsoil do. They generalize....the oil lifemonitor is very specific for that application. Oil condition sensors in some BMW and Mercedes products are useful, also. Theyhave their limitations, though, as they can be blind to some contaminates andcan, themselves, be contaminated by certain markers or constituents of certainengine oils. Oil condition sensors can only react to the specific oil at thatmoment and they add complexity, cost and another potential item to fail. Oneother beauty of the GM oil life monitor is that it is all software and does notadd any mechanical complexity, mass, wiring or potential failure mechanism. There is considerable safety factor in the GM oil life monitor. Typically, Iwould say, there is a 2:1 safety factor in the slope of the ZDP depletioncurve....in other words, zero percent oil life per the ZDP depletion is notzero ZDP but twice the concentration of ZDP considered critical for THAT engineto operate under all conditions reliably with no wear. This is always a subjectof 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 tendto be on the conservative side. If the oil life is counting down on a slopethat would recommend a 10K change interval then there is probably 20K oil lifebefore the ZDP is catostrophically depleted....not that you would want to go there...butreason why many people are successful in running those change intervals. Please...NOT ALL ENGINES ARE THE SAME. The example above is an excellentpractical justification of why you would want to add EOS and change the 15W40Delvac in the muscle car at 3000 miles max and yet can run the Northstar to12500 easily on conventional oil. You must treat each engine and situationdifferently and what applies to one does not retroactively apply to others.This is where Amsoil falls short in my book by proposing long change intervalsin most everything if you use their oil. It just doesn't work that way. You canrun the Amsoil to 12500 with no concerns whatsoever in the late model Northstarbecause even the oil life monitor tells you that for conventional oil off theshelf. Would I do that to the 502 in my 66 Chevelle...NO WAY. Amsoil says I canthough. Wrong. There are entire SAE papers written on the GM oil life monitor and one couldwrite a book on it so it is hard to touch on all aspects of it in a singlepost. Hopefully we hit the high spots. Realize that a GREAT deal of time, workand energy went into developing the oil life monitor and it has receivedacclaim from engineering organizations, petroleum organizations, environmentalgroups all across the board. It is not some widget invented in a week andtacked onto the car. The oil life monitor is not under the control of a summer intern at GMPowertrain per an earlier post....LOL Not that a summer intern wasn't compilingcalibrations or doing a project on it but is under control of the lube groupwith a variety of engineers directly responsible that have immediateresponsibility for the different engine families and engine groups. The ideathat a summer intern was responsible for or handling the oil life monitor isludicrous.....LOL LOL LOL 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 June 10, 2011 Report Share Posted June 10, 2011 Follow the oil life monitor - I know it is hard to get used to but the OLM works. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
cdgrinci Posted June 10, 2011 Report Share Posted June 10, 2011 OLM or one year, it's just that easy. Thanks for the article Mike; I was already convinced but now am doubly so. Chuck '19 CT6, '04 Bravada........but still lusting for that '69 Z-28 Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 10, 2011 Report Share Posted June 10, 2011 OLM or one year, it's just that easy. Thanks for the article Mike; I was already convinced but now am doubly so. Glad to help! 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...
cadillacjeff7777 Posted June 10, 2011 Author Report Share Posted June 10, 2011 Awesome info! Thanks Mike! I am thinking that I am going to go get the oil changed anyway...this time. The last oil change was done by the dealer (non-Cadillac) and as they change the oil on every car, they probably do not use synthetic. 2008 DTS Link to comment Share on other sites More sharing options...
cadillacjeff7777 Posted June 10, 2011 Author Report Share Posted June 10, 2011 I called the Cadillac dealer. $90-$95 for the oil change. That is fine but their hours match mine and I can not get over there for an oil change. Walmart will do it with Mobile 1 but I will have to pay the extra for the higher oil capacity and the "Included" oil filter is a 5K one which can be upgraded to a 10K for additional money. I have not called the Mobile Quick Lube place yet. Is a 10k filter good enough or is there one that is recommended to be better? 2008 DTS Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 11, 2011 Report Share Posted June 11, 2011 I dont know what anyone else thinks, but I would stay away from the mobile quick lube places GM is having a special right now, I saw it on TV and on my local Caddy dealer site, check yours, $29.95 (conventional oil), don't know what the synthetic is, but, its worth checking Here is the deal at my local dealer http://www.kingorourke.com/Service-Specials 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...
cadillacjeff7777 Posted June 11, 2011 Author Report Share Posted June 11, 2011 I dont know what anyone else thinks, but I would stay away from the mobile quick lube places GM is having a special right now, I saw it on TV and on my local Caddy dealer site, check yours, $29.95 (conventional oil), don't know what the synthetic is, but, its worth checking Here is the deal at my local dealer http://www.kingorourke.com/Service-Specials Well, the dealer here is closed on the weekend. I don't know if I should wait until next week and go on a lunch hour. 8,000 miles on what is suspected to be conventional oil? Any thoughts? 2008 DTS Link to comment Share on other sites More sharing options...
Texas Jim Posted June 11, 2011 Report Share Posted June 11, 2011 I dont know what anyone else thinks, but I would stay away from the mobile quick lube places GM is having a special right now, I saw it on TV and on my local Caddy dealer site, check yours, $29.95 (conventional oil), don't know what the synthetic is, but, its worth checking Here is the deal at my local dealer http://www.kingorour...ervice-Specials Well, the dealer here is closed on the weekend. I don't know if I should wait until next week and go on a lunch hour. 8,000 miles on what is suspected to be conventional oil? Any thoughts? Just my opinion... if I thought it was conventional oil... I would change it... Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 11, 2011 Report Share Posted June 11, 2011 Ditto 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...
cadillacjeff7777 Posted June 11, 2011 Author Report Share Posted June 11, 2011 What filter should I get? 2008 DTS Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 11, 2011 Report Share Posted June 11, 2011 What filter should I get? AC Delco of course! 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...
cadillacjeff7777 Posted June 11, 2011 Author Report Share Posted June 11, 2011 What filter should I get? AC Delco of course! So no go on the Mobile 1 filter? 2008 DTS Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 11, 2011 Report Share Posted June 11, 2011 What filter should I get? AC Delco of course! So no go on the Mobile 1 filter? Good Point, I would see what the dealer uses and use that. Oil filters boarder on OIL discussions and if you are not aware of it, we try to avoil discussions about oil. (long story). The problem I have with experimenting is that, GM when they built the Northstar designed the oil system specifically for the NS, its kind of unique. They validate the oil filter to function with that oil system. The guru once said, the most important filter an engine ever sees is its first filter that picks up manufacturing by products and debris. That said, I would want to use a filter that GM choses for this engine, by pass threshold and filtering level can impact efficiency. A few years ago there were filters that (I jumped on) claimed to filter down to like 5 microns.... what they found out was that it was overkill and that it could actually cause flow issues especially when cold. When is TOO MUCH of a good thing, too much?, if you know what I mean. 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...
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