Oil Life
04-23-2018, 01:05 AM
#21
Race Director
It's actually quite common for direct injected cars to see higher levels of fuel getting into the oil, I see it all the time on oil analysis reports from many direct injected vehicles of all makes, and on my very first oil analysis with my C7 I had 2% fuel in my oil even though that oil had only 1100 miles on it (this level of fuel in the oil caused it to thin out to a 5w20 actually, so I was glad I changed it early even though my wet sump car doesn't call for an early change). I do believe that 2% level was higher than normal due to the engine going through a lot of cold starts and shutdowns at the factory, on a fresh engine with rings that might not have been fully seated as well. But the truth of the matter is, even engines that aren't direct injected can see high levels of fuel getting into the oil if they are subjected to a lot of short trips.
04-23-2018, 03:48 AM
#22
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Thanks for the replies. It's not that I'm cheap, don't want to change oil once a year, or that I worry about the warranty.
My question was more along the lines of why you could put oil in the engine, never start it, and after a year the OLM would register 0% and require a new oil change when oil can sit on the shelf for 5 years and still be ok to use.
I can understand contamination from cold starts, not getting the oil up to temperature, etc. once the engine has been started. In fact, I can even understand water condensation hurting the oil without the engine ever being started. I like the OLM and think it is a good tool to use for oil monitoring but was curious what others thought about the OLM showing 0% after a year of engine non-use.
My question was more along the lines of why you could put oil in the engine, never start it, and after a year the OLM would register 0% and require a new oil change when oil can sit on the shelf for 5 years and still be ok to use.
I can understand contamination from cold starts, not getting the oil up to temperature, etc. once the engine has been started. In fact, I can even understand water condensation hurting the oil without the engine ever being started. I like the OLM and think it is a good tool to use for oil monitoring but was curious what others thought about the OLM showing 0% after a year of engine non-use.
04-23-2018, 04:16 AM
#23
These oil discussions always give me a chuckle - that 100% synthetic oil sitting in the crankcase is as good on day 365 as it was the day it was put in there. Nothing is "breaking down", no "acids being formed overt time", etc. If you don't believe me, you can drain it out and send it to Blackstone for oil analysis side-by-side with a sample out of a brand new bottle.
Whether or not you want to cheap out on $50 worth of oil and a filter (ok, $65 on a Z51) on your $70,000 car once a year is another matter entirely.
Greg
Whether or not you want to cheap out on $50 worth of oil and a filter (ok, $65 on a Z51) on your $70,000 car once a year is another matter entirely.
Greg
Last edited by hammong; 04-23-2018 at 04:17 AM.
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FunDriver (04-23-2018)
04-23-2018, 07:21 AM
#24
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I'm sure the engineers who researched and designed the OLM system didn't consider making those people happy who change their oil then don't drive for a year. They're engineering for the masses. In the end, a year is a year, even if you only store the oil in your engine.
We frequently see posters who're shocked to see the OLM showing a low percentage when the mileage on the oil is also low. Their year's oil life is about up so the low life remaining. At this point it's a mental thing we must adjust to. In the old days we'd track our oil life by odometer and calendar. As the year was closing on our annual oil change for low mileage cars we'd think "Gotta change the oil soon in the Vette." No big deal. We didn't think "Darn, I've only got 20% oil life left." Now we get a computer to tell us something like 20% oil life and we wonder why is the oil almost "old". Its really the same, just not our own thoughts about a year's time. The computer is the one saying "Gotta change the oil soon in the Vette." It takes some of us by surprise the first time. It did me until I got a better understanding of it.
We frequently see posters who're shocked to see the OLM showing a low percentage when the mileage on the oil is also low. Their year's oil life is about up so the low life remaining. At this point it's a mental thing we must adjust to. In the old days we'd track our oil life by odometer and calendar. As the year was closing on our annual oil change for low mileage cars we'd think "Gotta change the oil soon in the Vette." No big deal. We didn't think "Darn, I've only got 20% oil life left." Now we get a computer to tell us something like 20% oil life and we wonder why is the oil almost "old". Its really the same, just not our own thoughts about a year's time. The computer is the one saying "Gotta change the oil soon in the Vette." It takes some of us by surprise the first time. It did me until I got a better understanding of it.
04-23-2018, 08:17 AM
#25
E-Ray, 3LZ, ZER, LIFT
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Forgetting the foolish hypothetical, "If you change the oil and never start the car in a year will the oil be contaminated or oxidize" I chuckle at all the "wannabe automotive engineers" on this forum who are shocked when they are told the C7 is saying change the oil at one year regardless of miles driven etc etc.
Just checked and this is what it said in the Owner's Manual for my 1993 Vette for normal use: Change engine oil every 7500 miles or 12 months!
That same Owner's Manual (when there was no OLM) states severe service is where most trips are less than 4 miles change oil every 3000 miles or 3 months! So all you owner's who just use the car to go to a store 2-3 miles away, put on very few miles annually and think you don't need to change oil-think again!
Decades before 1993 "real automotive engineers" knew all about combustion products getting into the oil especially on cold starts and the need to have the oil get hot enough to evaporate some!
True Synthetic Oil:
I was using a "true synthetic" Mobil 1 in 1993 and changed every year as a minimum! Been using Mobil 1 since 1974 in my Corvair and 260Z at that time. It was produced from man made molecules through about ~2000 when Castrol used the term "synthetic" for a more highly refined Dino oil. Mobil tried to get Castrol to stop using the term but lost a lawsuit and could not! Mobil and others were forced to use that cheap refining approach as it cost 1/2 of the former "true synthetic!" oil! Mobil 1 prices did drop in about half!
Change At 1 Year (or less) Has Been in Existence for Many Years:
This one year requirement is not new! It's just that the C7 now keeps track of time!
It appears there are still folks who never read the Owner's Manual or didn't believe what it says!
Just checked and this is what it said in the Owner's Manual for my 1993 Vette for normal use: Change engine oil every 7500 miles or 12 months!
That same Owner's Manual (when there was no OLM) states severe service is where most trips are less than 4 miles change oil every 3000 miles or 3 months! So all you owner's who just use the car to go to a store 2-3 miles away, put on very few miles annually and think you don't need to change oil-think again!
Decades before 1993 "real automotive engineers" knew all about combustion products getting into the oil especially on cold starts and the need to have the oil get hot enough to evaporate some!
True Synthetic Oil:
I was using a "true synthetic" Mobil 1 in 1993 and changed every year as a minimum! Been using Mobil 1 since 1974 in my Corvair and 260Z at that time. It was produced from man made molecules through about ~2000 when Castrol used the term "synthetic" for a more highly refined Dino oil. Mobil tried to get Castrol to stop using the term but lost a lawsuit and could not! Mobil and others were forced to use that cheap refining approach as it cost 1/2 of the former "true synthetic!" oil! Mobil 1 prices did drop in about half!
Change At 1 Year (or less) Has Been in Existence for Many Years:
This one year requirement is not new! It's just that the C7 now keeps track of time!
It appears there are still folks who never read the Owner's Manual or didn't believe what it says!
Last edited by JerryU; 04-23-2018 at 08:30 AM.
04-23-2018, 05:49 PM
#26
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This makes me wonder about something else. I have a GM charger for the C7 but if you don't have a charger how bad is it to start the car and let it idle until it gets warm every few weeks to recharge the battery? From what has been said, that sounds like a bad idea so would it be better to disconnect the battery if the car isn't used much during winter, etc?
04-23-2018, 06:46 PM
#27
E-Ray, 3LZ, ZER, LIFT
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^^^
IMO best to keep a charger on it. Even if not connected to anything the battery will self discharge. My Street Rod's Yellow Top Optima is 8 1/2 years old! It is always on a charger! It mostly just goes to car shows.
Posted that the other day and said I was probably operating on borrowed time and should replace it. Feel bad as it started right up Saturday going to a show and started fine to come home! However it has electric doors that only open with a remote and the battery is inside the car in the rear! Would be no fun jumping!
Bought a replacement yesterday on the Net and it will be here Thursday! Hope it lasts as long!
IMO best to keep a charger on it. Even if not connected to anything the battery will self discharge. My Street Rod's Yellow Top Optima is 8 1/2 years old! It is always on a charger! It mostly just goes to car shows.
Posted that the other day and said I was probably operating on borrowed time and should replace it. Feel bad as it started right up Saturday going to a show and started fine to come home! However it has electric doors that only open with a remote and the battery is inside the car in the rear! Would be no fun jumping!
Bought a replacement yesterday on the Net and it will be here Thursday! Hope it lasts as long!
Last edited by JerryU; 04-23-2018 at 06:47 PM.
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FunDriver (04-23-2018)
05-02-2018, 08:46 AM
#28
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The problem with the time component is that we don't know if it artificially shortens the oil time.
Does my % tick down faster and possibly cause me to change "good" oil at less than 12 months because the time value influences the overall %? No one really knows. The % is just a number, and mostly meaningless in terms of overall time. The only value that matters is 100% and 0%, the % in between don't "mean" anything per say.
If someone could guarantee that I can get the same # of miles out of my oil change per year with the C7 algorithm versus the C6 algorithm then the time component doesn't bother me. But as of now, based on how the time component destroys the % while the car is in storage, it's not very comforting.
Does my % tick down faster and possibly cause me to change "good" oil at less than 12 months because the time value influences the overall %? No one really knows. The % is just a number, and mostly meaningless in terms of overall time. The only value that matters is 100% and 0%, the % in between don't "mean" anything per say.
If someone could guarantee that I can get the same # of miles out of my oil change per year with the C7 algorithm versus the C6 algorithm then the time component doesn't bother me. But as of now, based on how the time component destroys the % while the car is in storage, it's not very comforting.
05-02-2018, 09:03 AM
#29
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^^
I know we have had this discussion before BUT it is no different from what it said in my '93 Vette Owner's Manual I recently read; 7500 miles or one year whichever occurs first. Assuming your not just making 3 mile trips to the store then the OLM will get to about 7500 miles OR at one year say to change! Makes no difference, except physiological what it says in-between that year! Understand looking at the value right after a winter storage is an irritant to some! But one year after the last change it will make no difference, assuming you don't drive 6000 to 7000 miles/year!
When I looked up the '93 Owner's Manual info I found that it also said: "If most trips are less than 4 miles change oil at 3000 miles or 3 months, whichever occurs first." Some who only use their C7 for mostly trips <4 miles to the store may not believe that, but it is what it said. In fact the C7 OLM algorithm looks for oil temp after a start and if it does not get hot enough long enough will shorten the time to change!
I also find it interesting the OLM uses engine revolutions! Yep in the "old days" there was only an odometer so "miles was a fine indicator." But a mile around town is much worse for the engine than a mile driven on a highway!
Just Sayn'!
I know we have had this discussion before BUT it is no different from what it said in my '93 Vette Owner's Manual I recently read; 7500 miles or one year whichever occurs first. Assuming your not just making 3 mile trips to the store then the OLM will get to about 7500 miles OR at one year say to change! Makes no difference, except physiological what it says in-between that year! Understand looking at the value right after a winter storage is an irritant to some! But one year after the last change it will make no difference, assuming you don't drive 6000 to 7000 miles/year!
When I looked up the '93 Owner's Manual info I found that it also said: "If most trips are less than 4 miles change oil at 3000 miles or 3 months, whichever occurs first." Some who only use their C7 for mostly trips <4 miles to the store may not believe that, but it is what it said. In fact the C7 OLM algorithm looks for oil temp after a start and if it does not get hot enough long enough will shorten the time to change!
I also find it interesting the OLM uses engine revolutions! Yep in the "old days" there was only an odometer so "miles was a fine indicator." But a mile around town is much worse for the engine than a mile driven on a highway!
Just Sayn'!
Last edited by JerryU; 05-02-2018 at 09:05 AM.
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Boiler_81 (05-02-2018)
05-02-2018, 09:17 AM
#30
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Jerry, I'm not arguing about the 1 year oil change.
I'm arguing that the time component will artificially reduce the number of miles you can drive on one oil change in LESS than 12 months.
I only have anecdotal evidence. But based on my usage, I never had to change my oil until it reached the 1 year mark with my C6 because the OLM never got below 20% (and I averaged 8000 miles a year in the beginning, mostly 20+ mile trips). My C7 was very low (10%-15%) when I put it away both of the last two years and I drove 7500 the first year and less the second year.
I'm worried that the time component is potentially taking 1000-1500 miles off my less than 12 month oil change. My goal is to drive over 8000 miles this year and see if it does in fact hit 0% before I put it away. If it does then I will declare the algorithm suspect and artificially reducing mileage.
I should get 9000 miles per change based on my driving style.
I'm arguing that the time component will artificially reduce the number of miles you can drive on one oil change in LESS than 12 months.
I only have anecdotal evidence. But based on my usage, I never had to change my oil until it reached the 1 year mark with my C6 because the OLM never got below 20% (and I averaged 8000 miles a year in the beginning, mostly 20+ mile trips). My C7 was very low (10%-15%) when I put it away both of the last two years and I drove 7500 the first year and less the second year.
I'm worried that the time component is potentially taking 1000-1500 miles off my less than 12 month oil change. My goal is to drive over 8000 miles this year and see if it does in fact hit 0% before I put it away. If it does then I will declare the algorithm suspect and artificially reducing mileage.
I should get 9000 miles per change based on my driving style.
Last edited by LT1 Z51; 05-02-2018 at 09:18 AM.
05-02-2018, 09:36 AM
#31
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^^
Suspect you will get the year! Only time will tell.
Suspect you will get the year! Only time will tell.
Last edited by JerryU; 05-02-2018 at 09:37 AM.
05-02-2018, 11:26 AM
#32
Drifting
05-02-2018, 11:49 AM
#33
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^^
It does, time is just in case. It also keeps track of starts and the temp and time the oil reaches after a start. If the car is just driven mostly on short trips, especially dry sumps that take longer to heat the oil, it will reduce the time needed to change. That is better than what my ‘93 Vette Owner’s Manual said, which is if most trips are below 4 miles change oil at 3000 miles or 3 months which ever occurs first! There are other parameters it measures as well.
It does, time is just in case. It also keeps track of starts and the temp and time the oil reaches after a start. If the car is just driven mostly on short trips, especially dry sumps that take longer to heat the oil, it will reduce the time needed to change. That is better than what my ‘93 Vette Owner’s Manual said, which is if most trips are below 4 miles change oil at 3000 miles or 3 months which ever occurs first! There are other parameters it measures as well.
Last edited by JerryU; 05-02-2018 at 11:55 AM.
05-02-2018, 12:04 PM
#34
Burning Brakes
For those that have to unfortunately store their cars for a portion of the year, I have an idea. Change you oil as usual before storage but do not reset the oil life monitor. Leave yourself a note in the car or on the steering wheel to reset the oil life monitor in the spring. This way you get to store your car with clean oil and get to start the driving season at 100%.
05-02-2018, 12:34 PM
#35
Drifting
^^
It does, time is just in case. It also keeps track of starts and the temp and time the oil reaches after a start. If the car is just driven mostly on short trips, especially dry sumps that take longer to heat the oil, it will reduce the time needed to change. That is better than what my ‘93 Vette Owner’s Manual said, which is if most trips are below 4 miles change oil at 3000 miles or 3 months which ever occurs first! There are other parameters it measures as well.
It does, time is just in case. It also keeps track of starts and the temp and time the oil reaches after a start. If the car is just driven mostly on short trips, especially dry sumps that take longer to heat the oil, it will reduce the time needed to change. That is better than what my ‘93 Vette Owner’s Manual said, which is if most trips are below 4 miles change oil at 3000 miles or 3 months which ever occurs first! There are other parameters it measures as well.
05-02-2018, 12:53 PM
#36
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I just worry because the intervening % values seem so basket case.