Scheduled Maintenance....oil Change

[terzmo]

My Son and I have the same 2010 silverado's...5.3/6 speed....bought at 2 different dealers. Mine schedules the oil to be changed at 6000 mile intervals...His schedules at 3000 mile intervals ??

 

What's everyone's else schedule ??

[2016 Sierra Owner]

I change mine at 3 months/3000 miles not matter what the book or anyone else says. It's cheap insurance.

[KMGZ400]

its basically your prefrence when you want to change your oil. i change it around 3k becasue i feel its necessary. i wouldnt go more then 6k.

[jwhjr]

The OLM

[txab]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

[Zembonez]

OH GOODY.

 

Another thread where everybody voices their "correct" opinion on when oil should be changed.

[Z45]

I read a statistic recently that said 90% of US drivers are still stuck on the 3,000 mile oil change much to the delight of the oil companies and the lube service industry.

[mxdirtrider56]

OH GOODY.

 

Another thread where everybody voices their "correct" opinion on when oil should be changed.

 

 

Some milk duds would go well with this.

[dlstewart01]

 

http://theweek.com/article/index/207073/th...oil-change-myth

[terzmo]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

 

 

This oil change thing is really getting overboard with suggesting a sample be taken to a lab.....I'll just rely on the 100000 mile warranty...don't plan on having it past that. This OLM thing....Within how many miles of a change does it ativate...My wife's jeep starts commercials when 100 miles from a suggested change. AND...so it's the general opinion the "dealer" sets the OLM ???

[Matt_]

Change my oil and rotate my tires every 5,000 miles.

 

its a nice round figure...

 

1) not too short by most standards (OLM usually dings at 7000-7500)

2) not too long by most standards (for synthetic)

3) easy to remember.... if you can divide by 5 then you'll always know when an oil change is coming up

 

if 5000 miles is "wrong", then at least its the best wrong way to do it, IMO of course

[txab]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

 

 

This oil change thing is really getting overboard with suggesting a sample be taken to a lab.....I'll just rely on the 100000 mile warranty...don't plan on having it past that. This OLM thing....Within how many miles of a change does it ativate...My wife's jeep starts commercials when 100 miles from a suggested change. AND...so it's the general opinion the "dealer" sets the OLM ???

 

 

I do 5k intervals but know I can go further than that if I choose to. The sample testing suggestion is only for those who need something concrete to prove to themselves one way or the other that their interval is within safe limits or that it can be extended somewhat. Lastly it is for peace of mind for those people who doubt. Too many people still hung up on the 3k drain interval. You don't sample every oil change. It costs maybe $20. Your 6k interval is fine no doubt as long as you're using a quality oil, and quality oil filter. Your son on the other hand is spending extra money unnecessarily, IMHO. Bottom line is, do what you feel comfortable with.

 

Do your trucks have a DIC, if so you are able to monitor the percentage of oil life left. The OLM is reset to 100% at oil change time. The dealer cannot change any of the parameters of how the OLM works. The OLM is pretty accurate. All of our equipment is sample tested for changes of oils and lubes. All of the GM products pretty much match up with what the OLM says.

 

Below is an explanation of the OLM system

 

Oil Life Monitor

 

http://www.gm-trucks.com/forums/index.php?...st&p=962885

 

See how the GM OLM works...

 

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 ZDDP 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 ZDDP 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 ZDDP 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 ZDDP depletion curve....in other words, zero percent oil life per the ZDDP depletion is not zero ZDDP 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 ZDDP 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 ZDDP 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.

[terzmo]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

 

 

This oil change thing is really getting overboard with suggesting a sample be taken to a lab.....I'll just rely on the 100000 mile warranty...don't plan on having it past that. This OLM thing....Within how many miles of a change does it ativate...My wife's jeep starts commercials when 100 miles from a suggested change. AND...so it's the general opinion the "dealer" sets the OLM ???

 

 

I do 5k intervals but know I can go further than that if I choose to. The sample testing suggestion is only for those who need something concrete to prove to themselves one way or the other that their interval is within safe limits or that it can be extended somewhat. Lastly it is for peace of mind for those people who doubt. Too many people still hung up on the 3k drain interval. You don't sample every oil change. It costs maybe $20. Your 6k interval is fine no doubt as long as you're using a quality oil, and quality oil filter. Your son on the other hand is spending extra money unnecessarily, IMHO. Bottom line is, do what you feel comfortable with.

 

Do your trucks have a DIC, if so you are able to monitor the percentage of oil life left. The OLM is reset to 100% at oil change time. The dealer cannot change any of the parameters of how the OLM works. The OLM is pretty accurate. All of our equipment is sample tested for changes of oils and lubes. All of the GM products pretty much match up with what the OLM says.

 

Below is an explanation of the OLM system

 

Oil Life Monitor

 

http://www.gm-trucks.com/forums/index.php?...st&p=962885

 

See how the GM OLM works...

 

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 ZDDP 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 ZDDP 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 ZDDP 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 ZDDP depletion curve....in other words, zero percent oil life per the ZDDP depletion is not zero ZDDP 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 ZDDP 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 ZDDP 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.

 

 

 

My truck doesn't have the DIC..I assume that is on My Son's as He can monitor fuel usage,projected miles left, etc...I only have direction,miles,resetable odometer..trans temp. No oil messages have showed up on My odometer like My wife's jeep. It comes on every 2900 miles. From previous posts I get the opinion the factory sets it at 7500 and everyone else is changing oil every 3 to 6,000 miles. I have 6300 on mine and will see what happens. My dealer did have Me come in at 3000 to check fluid levels, no charge, but has the truck on a 6000 mile schedule. My Son's dealer just had Him come in for a change at 3000 and has him on a 3k schedule.

 

How can the Factory honor the warranty with at least two dealer's with two different schedules....perhaps the owner's manual has an opinion....

 

My Friends new dodge is on a 7500 mile schedule...not that it matters to this vehicle.

 

OH, the dealer says the truck is replenished with GM oil....is that synthetic or not ??

[gleno97]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

 

 

This oil change thing is really getting overboard with suggesting a sample be taken to a lab.....I'll just rely on the 100000 mile warranty...don't plan on having it past that. This OLM thing....Within how many miles of a change does it ativate...My wife's jeep starts commercials when 100 miles from a suggested change. AND...so it's the general opinion the "dealer" sets the OLM ???

 

 

I do 5k intervals but know I can go further than that if I choose to. The sample testing suggestion is only for those who need something concrete to prove to themselves one way or the other that their interval is within safe limits or that it can be extended somewhat. Lastly it is for peace of mind for those people who doubt. Too many people still hung up on the 3k drain interval. You don't sample every oil change. It costs maybe $20. Your 6k interval is fine no doubt as long as you're using a quality oil, and quality oil filter. Your son on the other hand is spending extra money unnecessarily, IMHO. Bottom line is, do what you feel comfortable with.

 

Do your trucks have a DIC, if so you are able to monitor the percentage of oil life left. The OLM is reset to 100% at oil change time. The dealer cannot change any of the parameters of how the OLM works. The OLM is pretty accurate. All of our equipment is sample tested for changes of oils and lubes. All of the GM products pretty much match up with what the OLM says.

 

Below is an explanation of the OLM system

 

Oil Life Monitor

 

http://www.gm-trucks.com/forums/index.php?...st&p=962885

 

See how the GM OLM works...

 

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 ZDDP 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 ZDDP 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 ZDDP 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 ZDDP depletion curve....in other words, zero percent oil life per the ZDDP depletion is not zero ZDDP 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 ZDDP 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 ZDDP 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.

 

 

 

My truck doesn't have the DIC..I assume that is on My Son's as He can monitor fuel usage,projected miles left, etc...I only have direction,miles,resetable odometer..trans temp. No oil messages have showed up on My odometer like My wife's jeep. It comes on every 2900 miles. From previous posts I get the opinion the factory sets it at 7500 and everyone else is changing oil every 3 to 6,000 miles. I have 6300 on mine and will see what happens. My dealer did have Me come in at 3000 to check fluid levels, no charge, but has the truck on a 6000 mile schedule. My Son's dealer just had Him come in for a change at 3000 and has him on a 3k schedule.

 

How can the Factory honor the warranty with at least two dealer's with two different schedules....perhaps the owner's manual has an opinion....

 

My Friends new dodge is on a 7500 mile schedule...not that it matters to this vehicle.

 

OH, the dealer says the truck is replenished with GM oil....is that synthetic or not ??

 

Your truck will tell you the oil life info by inserting the key and turning it so the radio comes on without starting the engine then push the odometer button until your oil life info is displayed.

[terzmo]

Use a quality oil and filter, then go by the Oil Life Monitor that is included with your truck. Gm put it there for a reason. Your sons dealer likes making a few bucks.

 

Your 6k figure is fine. If you want peace of mind, have an oil sample tested by reputable lab and look at the results for yourself

 

 

 

BTW, 50% of the people here will say 3k the other 50% will say your 6k figure is fine. This topic is covered way too often and has the same responses. Again test an oil sample and you'll know what's good for your application

 

 

This oil change thing is really getting overboard with suggesting a sample be taken to a lab.....I'll just rely on the 100000 mile warranty...don't plan on having it past that. This OLM thing....Within how many miles of a change does it ativate...My wife's jeep starts commercials when 100 miles from a suggested change. AND...so it's the general opinion the "dealer" sets the OLM ???

 

 

I do 5k intervals but know I can go further than that if I choose to. The sample testing suggestion is only for those who need something concrete to prove to themselves one way or the other that their interval is within safe limits or that it can be extended somewhat. Lastly it is for peace of mind for those people who doubt. Too many people still hung up on the 3k drain interval. You don't sample every oil change. It costs maybe $20. Your 6k interval is fine no doubt as long as you're using a quality oil, and quality oil filter. Your son on the other hand is spending extra money unnecessarily, IMHO. Bottom line is, do what you feel comfortable with.

 

Do your trucks have a DIC, if so you are able to monitor the percentage of oil life left. The OLM is reset to 100% at oil change time. The dealer cannot change any of the parameters of how the OLM works. The OLM is pretty accurate. All of our equipment is sample tested for changes of oils and lubes. All of the GM products pretty much match up with what the OLM says.

 

Below is an explanation of the OLM system

 

Oil Life Monitor

 

http://www.gm-trucks.com/forums/index.php?...st&p=962885

 

See how the GM OLM works...

 

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 ZDDP 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 ZDDP 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 ZDDP 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 ZDDP depletion curve....in other words, zero percent oil life per the ZDDP depletion is not zero ZDDP 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 ZDDP 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 ZDDP 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.

 

 

 

My truck doesn't have the DIC..I assume that is on My Son's as He can monitor fuel usage,projected miles left, etc...I only have direction,miles,resetable odometer..trans temp. No oil messages have showed up on My odometer like My wife's jeep. It comes on every 2900 miles. From previous posts I get the opinion the factory sets it at 7500 and everyone else is changing oil every 3 to 6,000 miles. I have 6300 on mine and will see what happens. My dealer did have Me come in at 3000 to check fluid levels, no charge, but has the truck on a 6000 mile schedule. My Son's dealer just had Him come in for a change at 3000 and has him on a 3k schedule.

 

How can the Factory honor the warranty with at least two dealer's with two different schedules....perhaps the owner's manual has an opinion....

 

My Friends new dodge is on a 7500 mile schedule...not that it matters to this vehicle.

 

OH, the dealer says the truck is replenished with GM oil....is that synthetic or not ??

 

Your truck will tell you the oil life info by inserting the key and turning it so the radio comes on without starting the engine then push the odometer button until your oil life info is displayed.

 

 

 

cool...thanks...but isn't that going to show Me the remainder time on the last oil change from the dealer...and mine says every 6k....or is this derrived from the factory setting ??