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I recall reading this statement that was posted by Ranger from the Guru:

"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.".
Yes that is in my post above from the guru.... I think the problem is however, HOW MUCH has the ZDDP been reduced... Its nice that the OLM algorithm was conservative, but now that the ZDDP is reduced what is the margin of safety now? Is it down from 20K miles to 10K miles? I am not sure we will ever know that, as it would require lots of testing to re-establish the ZDDP depletion curve..
 
Ok so you people are thinking that ZDDP is the ONLY antiwear agent in the oil, but its not.
aftertalking with a chemical engineer I was informed that while yess some oils have REDUCED levels they are in no way counter productive nor in any way ,WITH NORMAL MAINTENANCE AND CARE, going to cause excessive wear.
As a technician I have been researching this greatly as a lot of Cadillac owners are interested and saying that I dont know what I am talking about even though I am a certified Master Gas Engine Machinist and a race engine builder.
now lots of engines I work on that are race engines have flat tappets and HIGH valve spring preasures and several are street driven and I guarantee you these engines get more abuse than what any of you can put on an engine.
The big problem I see with OLM changes are the oil comes out thin, diluted greatly, just plain grungy, and I would never let standard motor oil go that long. I have seen OLMs let oil go well over 15k miles and this is just too long.
I really like to see oil changes in any car with OLMs come it at 3k and see where the OLM has left. Honestly if I see more that 500 to 700 miles left (or a percentage coming near that.) I suspect the programing.
While it is considerered ok to go long miles with the OLM but I just dont trust a machine to tell me that I need to change my oil.
My father always held very strict oil change schedules. AND his vehicles all went to new owners who had very good luck with the condition of his vehicles.
And for 20 plus years we used Shell Rotella T in our vehicles. now I rune full synthetic oil. One of the reasons is that the base oil has higher temp stability, also you gotta remeber the oil does the lubricating and carries the additives arround, the ZDDP migrates to the metal parts and protects if the oil film breaks down. Now some the additives help the base oils hold up to the rigors inside the engine.
I have not seen any problems with cams lately. I have several engines that are closer to stock than most really would believe but we still run high lift cams with high spring rate valve springs, and so far even in older big block chevys i have never seen any problems and most of these guys have went with standard off the shelf oild rather than high dollar racing oils. I have one fella running a .650 lift race cam and its flat tappet and that engine gets driven every day to work. He rags that enige bad and it looks great.
IF you change the oil regularly I dont think your going to have any problems. The newer oils especially with synthetic blends are doing very well and regardless of a few supposed failures.
Generally if I find a bad cam the lifter has been wearing for a while. I find that if the engine is full of crud(from lack of oil changes and bad detergent packages) the lifters will stop turning in the lifter bore THEN you get lifter wear that will be excessive.
Come on guys you spend good money on your rides then want to play the wait game on oil changes. WHY? If the engine cost a lot to replace would it not be cheaper to change your oil more often?
I see Caddys with 150k , 200k and even more and never have cam problems. Like someone said I think a lot of this chicken little screaming the sky is falling.
If you dont like certain oils run the Shell Rotella, then you can sleep well at night.
Good Luck
 
I really like to see oil changes in any car with OLMs come it at 3k and see where the OLM has left. My father always held very strict oil change schedules. AND his vehicles all went to new owners who had very good luck with the condition of his vehicles.
I certainly don't have your qualifications, experience or knowledge, but come on now. 3K oil changes was correct for your father and mine. Hell even for me when I had my first few cars, but todays SM oils are a far cry from the SD oils that they used, don't you think?

Honestly if I see more that 500 to 700 miles left (or a percentage coming near that.) I suspect the programing.
Do you have any idea what went into the programming of the GM OLM algorithm? Do you realize the Dr. Shirley Schwartz holds a patent along with GM for it and has won awards for it and that she is very highly respected in the field of lubrication?

I would respectfully suggest that you are a bit closed minded and old school (as was I til I learned more about it). Old habits die hard and it took a long time for me to give up on the 3K oil changes. It took our old Guru and some lengthy detailed explanations to finally convince me. Maybe someone has a copy stored.

Come on guys you spend good money on your rides then want to play the wait game on oil changes. WHY? If the engine cost a lot to replace would it not be cheaper to change your oil more often?
Are you saying that following the OLM will cause an engine failure?
 
You know what, 3000 mile oil changes when we were kids was OVERKILL also... The manual said if you did short trips, fleet or stop and go change it every 3000 miles.... that was the WORST case scenario.... Highway driving it said every 7500 miles... So EVEN back then, changing it every 3000 miles was like wearing a belt and suspenders... The OLM takes MANY variables into consideration many that WE can not monitor easily... If you wear belts and suspenders change it every 3000 miles, hell you might as well change your tranny fluid every 24000 miles while you are at it also..
 
You know what, 3000 mile oil changes when we were kids was OVERKILL also... The manual said if you did short trips, fleet or stop and go change it every 3000 miles.... that was the WORST case scenario.... Highway driving it said every 7500 miles... So EVEN back then, changing it every 3000 miles was like wearing a belt and suspenders... The OLM takes MANY variables into consideration many that WE can not monitor easily... If you wear belts and suspenders change it every 3000 miles, hell you might as well change your tranny fluid every 24000 miles while you are at it also..
Gm Powertrain engineers decided that dirt introduced while monkeying with the transmission was enough of a factor to assemble the newer transmissions in a clean room and seal them after a factory fill and have no dipstick. My CTS has a dedicated OLM for the transmission. Projecting oil life indicates the OLM will time out at about 191,000 miles. I'll probably service it before then. I suspect there are a hell of a lot more cars get wrapped around a pole by a drunk that changes the oil at 3000 miles than destroyed by owners following the factory maintenance schedule.
 
hell you might as well change your tranny fluid every 24000 miles while you are at it also..

Your not far off, up until the late 90's when the electronically controlled 722.6 transmissions came out, Mercedes maintenance manual recommended changing the transmission fluid & filter every 30,000 miles.
 
Just picked up a couple of cases of Rotella 10W-30. It's the new Triple Protection but.... it's API rated SJ which was the spec in 1996. So next oil change I guess I'm officially switching from Mobil 1 10W30 EP to the Rotella. I reposted the Mobil 1 EP pic, you'll notice it's API rated SL & SM only, while the Rotella is SJ, SL & SM


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Your not far off, up until the late 90's when the electronically controlled 722.6 transmissions came out, Mercedes maintenance manual recommended changing the transmission fluid & filter every 30,000 miles.
My statement to change the tranny fluid every 24000 months was said tongue in cheek.... the reasons used for NOT using the OLM to me are ridiculous... Even the BITOG site confirmed that the OLM works.. Some people are just thick headed about it and INSIST on throwing out opinions like "the oil comes out TOO thin" without empirical data to back it up... FACTS are ALL I want to hear about.. Personally I trust the OLM because of the testing that went into it and because the guru would NOT steer us wrong. Anyone that disagrees should re-read the guru's words that I posted above and POST facts like OIL analysis when the OLM hits 50%, 25% and ZERO before refuting its accuracy. Opinions are like aholes, everyone has one, now FACTS, that's a different story.
 
Thanks for those articles, this came from your first article its identical to what I posted above:

The typical recommended interval for gasoline-fueled passenger cars and light-duty trucks is 3,000 miles (4,800 km) or three months, whichever first occurs, when outside temperatures are below freezing and trips are short. These conditions are considered severe duty. For ideal driving conditions, relating to long trips with mild outside temperatures, the interval can be expanded to 7,500 miles (12,000 km).

I love it! Changing your oil every 3000 miles is only necessary for SEVERE duty! I hate being right all the time, I really do, but it comes from paying attention and listening to people who are smarter than I am, and from not being old school and thick headed...and it has nothing to do with how many engines (429, 472, 500 and olds 350) I have rebuilt, transmissions (TH350, TH400) I have rebuilt or the four summers I was a first class mechanic in a ship yard working on pumps, cranes, and engines in my high school and college years in the early 70's, it has to do with being flexible and being open to learning new things and listening to people who are smarter than me by far. I think its called humility and I am not patting myself on the back.
 
On older engines with flat-tappet lifters, such as the 93-99 Northstar, the camshaft rubs across the lifters and ZDDP is used as a high pressure lubricant. It bonds to the surface of the cam and lifters leaving an ovelapping layer of lubricant.

With the phasing out of ZDDP to help with catalytic converter life (OEMs dont like to replace emissions systems under warranty) cams started going flat everywhere. To aggravate the situation, some detergents included in oils may wipe-out organic deposits (the precious ZDDP!) from engine surfaces.

CJ-4 reduces phosphorous content 200 PPM (not really all that significant -- from CI-4 1440 PPM to CJ-4 1200 PPM). Phosphorous is part of ZDDP so it can be considered a directly proportional reduction.

Chevron said:
Do I need to adjust my used oil analysis program for Chevron Delo 400 LE?
Yes,Delo 400 LE may have a different fresh oil chemical profile from previous oils because one ofthe key requirements ofthe API
CJ-4 category is the setting ofmaximum limits on the phosphorus,sulfur and sulfated ash content ofoils.These limits are needed to protect the
new2007 advanced emission control technologies.Users should seek guidance from their oil supplier and/or engine or vehicle manufacturer
regarding any changes to used oil analysis programs for Delo 400 LE.Chevron will be providing our new API CJ-4 product chemical profiles to
all labs that participatein our company-sponsored oil analysis programs.These programs include LubeWatch,Computex,and ChevronCheck.

http://www.delobike.com/Chev CJ4 Q_A.pdf
I think the sky IS falling for those of us with flat-tappet engines. j/k
:alchi:
 
With a 96 Deville, I agree and will follow what clarkz said above and supplement my oil changes with a pint of EOS or use Rotella from now on.
Here's my backyard science analysis on what EOS does to your oil concentration:
http://www.cadillacforums.com/forum...s/northstar-performance-technical-discussion/97572-oil-weight-4.html#post971843

One pint of EOS adds ~400PPM to the ZDDP concentration (to 7 qts.)

ILSAC GF-4 has about 800 PPM ZDDP so adding the pint of EOS to it will bring the oil up to 1200 PPM ZDDP

Likewise one bottle of 4 cyl STP has 2000 PPM ZDDP so adding that bottle (I believe also a pint) will add 133 PPM of ZDDP.
 
I am think about that on my wifes '96 3800. Anyone know if an '04 3.4 (Grand Am) is flat tappet or roller?
According to eSI, the camshaft is made from a new metal composite design (good luck j/k).

A "roller rocker" type valve train is used (not to be confused with "rock and roller," a term coined in the 60s with the advent of The Beatles). Motion is transmitted from the camshaft through the hydraulic roller lifter and from the pushrod to the roller rocker arm.
 
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