Time or Mileage for Synthetic Oil Change?
12-20-20, 05:47 PM
#61
Instructor
Thread Starter
I`m interested in what source articles OP is drawing from since you are not "sniffing" the oil or doing a UOA.
Time is relevant according to Lexus, who make it one of the qualifying criteria for the normal oil change interval. The only condition where it becomes irrelevant is when your driving habit is classified under "severe duty".
Time is relevant according to Lexus, who make it one of the qualifying criteria for the normal oil change interval. The only condition where it becomes irrelevant is when your driving habit is classified under "severe duty".
There are many other articles on the topic, but you can do your own research. If you find something relevant, by all means, please share it.
In 1983, I purchased a brand new Pontiac Firebird and put Mobil 1 synthetic oil in it exclusively until I sold it to a close friend in 1987 with 75,000 miles. He drove in up to more than 150,000 miles and continued the practice. The engine ran flawlessly the whole time. So I'm very familiar with synthetic oil, having researched it and signed on to it 37 years ago.
I think many people, present company included, make the mistake of applying the old rules that apply to traditional petroleum based oil to synthetic oil. Many of these old rules don't apply to synthetic oil because it essentially doesn't break down, it just gets dirty. For example, even though tolian21 came around to the position that "Time is mostly not relevant," he still thinks that synthetic oil degrades when contaminated by small amounts of fuel, just because traditional petroleum based oil does. I don't make that leap of logic without some good data or logic. Synthetic oil can withstand much more stress from temperature extremes, pressure, etc, than traditional oil without degradation. My inclination is to think that synthetic oils stands up to fuel dilution contamination much better than traditional oil until someone convinces me otherwise.
12-20-20, 07:18 PM
#62
Any oil, including synthetic degrades when exposed to contaminants. Read all the small print for Mobil1 and Amsoil, they’ll tell you one year maximum.
Synthetic is just more resilient and it takes longer for it to degrade, but it will still degrade.
If oil is diluted with gas above normal levels, synthetic oil is not going to help and oil needs to be changed soon. There is no such thing as oil “standing up” to fuel dilution. One of the problems with all the information on internet about “miracles of synthetic oil” is that people expect too much from it. It’s not that simple.
Synthetic is just more resilient and it takes longer for it to degrade, but it will still degrade.
If oil is diluted with gas above normal levels, synthetic oil is not going to help and oil needs to be changed soon. There is no such thing as oil “standing up” to fuel dilution. One of the problems with all the information on internet about “miracles of synthetic oil” is that people expect too much from it. It’s not that simple.
Last edited by tolian21; 12-20-20 at 07:40 PM.
12-20-20, 08:18 PM
#63
There's a large and glaring flaw in your logic. Let me illustrate with an example.
Let's say Driver A does 1,000 miles a month. Let's also say that each month results in X% of fuel dilution. Therefore, after 6 months, the oil is diluted by 6X%.
Driver B does 500 miles a month and has the same driving habits as Driver A, just less frequent driving. Therefore, after 6 months, the oil is diluted by 3X%.
You can do another example with different driving habits, but you'll get the same result. It's totally a factor of miles and driving habits. Time has nothing to do with it.
Let's say Driver A does 1,000 miles a month. Let's also say that each month results in X% of fuel dilution. Therefore, after 6 months, the oil is diluted by 6X%.
Driver B does 500 miles a month and has the same driving habits as Driver A, just less frequent driving. Therefore, after 6 months, the oil is diluted by 3X%.
You can do another example with different driving habits, but you'll get the same result. It's totally a factor of miles and driving habits. Time has nothing to do with it.
12-20-20, 09:42 PM
#64
Lead Lap
Here's a CarandDriver article on synthetic oil change frequency. It's interesting to note that there's not even a mention of time intervals. Only mileage intervals.
There are many other articles on the topic, but you can do your own research. If you find something relevant, by all means, please share it.
In 1983, I purchased a brand new Pontiac Firebird and put Mobil 1 synthetic oil in it exclusively until I sold it to a close friend in 1987 with 75,000 miles. He drove in up to more than 150,000 miles and continued the practice. The engine ran flawlessly the whole time. So I'm very familiar with synthetic oil, having researched it and signed on to it 37 years ago.
I think many people, present company included, make the mistake of applying the old rules that apply to traditional petroleum based oil to synthetic oil. Many of these old rules don't apply to synthetic oil because it essentially doesn't break down, it just gets dirty. For example, even though tolian21 came around to the position that "Time is mostly not relevant," he still thinks that synthetic oil degrades when contaminated by small amounts of fuel, just because traditional petroleum based oil does. I don't make that leap of logic without some good data or logic. Synthetic oil can withstand much more stress from temperature extremes, pressure, etc, than traditional oil without degradation. My inclination is to think that synthetic oils stands up to fuel dilution contamination much better than traditional oil until someone convinces me otherwise.
There are many other articles on the topic, but you can do your own research. If you find something relevant, by all means, please share it.
In 1983, I purchased a brand new Pontiac Firebird and put Mobil 1 synthetic oil in it exclusively until I sold it to a close friend in 1987 with 75,000 miles. He drove in up to more than 150,000 miles and continued the practice. The engine ran flawlessly the whole time. So I'm very familiar with synthetic oil, having researched it and signed on to it 37 years ago.
I think many people, present company included, make the mistake of applying the old rules that apply to traditional petroleum based oil to synthetic oil. Many of these old rules don't apply to synthetic oil because it essentially doesn't break down, it just gets dirty. For example, even though tolian21 came around to the position that "Time is mostly not relevant," he still thinks that synthetic oil degrades when contaminated by small amounts of fuel, just because traditional petroleum based oil does. I don't make that leap of logic without some good data or logic. Synthetic oil can withstand much more stress from temperature extremes, pressure, etc, than traditional oil without degradation. My inclination is to think that synthetic oils stands up to fuel dilution contamination much better than traditional oil until someone convinces me otherwise.
There's a lot of nonsense floating around about when to change your synthetic oil. If your vehicle runs synthetics—and most do these days—the best place to find the correct oil-change interval is the owner's manual.
Another data point is the list by Mobil
https://www.mobil.com/en/lubricants/...s/product-faqs
If you drill down even further by line of oil and do a comparo you can see that time and mileage are both qualifiers for service intervals. However Mobil lists some conditions like severe duty in a car manual that overrule their standard time/mileage limits.
Regardless their max limit for oil life is 1 year or 20k miles, whichever comes first in normal use from mobil.
Last edited by coolsaber; 12-20-20 at 09:46 PM.
12-20-20, 09:48 PM
#65
Lead Lap
The flaw in your logic is that oil dilution is not necessarily additive over time. Once an engine is fully warmed up so the oil (not just the water/antifreeze) is at operating temperature (probably around 250 degrees F requiring perhaps 10-20 miles of driving), then most of the fuel dissolved in the oil is distilled/burnt off. In other words, although fuel dilution will build up following a consecutive series of very short runs, once the car is driven to oil operating temps most of the fuel will be driven from the oil.
12-21-20, 12:29 AM
#66
12-21-20, 04:38 AM
#67
I am surprised that latest Lexus models do not use OLM that is based on actual driving characteristics rather than fixed time and milage. Honda has had OLM monitoring for years that would take into consideration motor hours, number of cold starts and other things to estimate oil life.
12-21-20, 12:59 PM
#68
In some sense, OLMs are worse than useless since they can lull an owner who HASN'T read the oil change maintenance fine print in the owner's manual into not performing the manual's required oil changes necessary to avoid voiding the warranty. For example, a lot of the owner's manuals have a fine print footnote stating that no matter what the OLM system indicates there is a maximum time interval that can lapse (usually one year) before an oil and filter change must be accomplished. Some also have the requirement that if one fails to reset the OLM system after an oil change and driving an OEM specified number of miles (some as few a just a few tens of miles) then one must revert to changing the oil and filter regardless the OLM system reading within a set number of miles (e.g., 3000 miles in some manuals).
If a Maintenance Minder message does not appear more than 12 months after the display is reset, change the engine oil every year.
12-21-20, 02:47 PM
#69
I disagree, Honda OLM is a much better approximation for an oil change compared to fixed milage interval. Its not ideal, but it will come on early in city driving vs highway. Its better than nothing. It counts motor hours and other things. Since 2019 Honda OLM will alert at 12 month even if you have very low milage.
10k fixed milage can not accommodate all types of driving conditions that vary for different people.
I would not call Honda’s OLM as “stupid”, one thing Honda does well is build engines (I cant say this for the rest). Honda’s engine reputation has been pretty solid, and definitely among the best
10k fixed milage can not accommodate all types of driving conditions that vary for different people.
I would not call Honda’s OLM as “stupid”, one thing Honda does well is build engines (I cant say this for the rest). Honda’s engine reputation has been pretty solid, and definitely among the best
Last edited by tolian21; 12-21-20 at 03:30 PM.
12-21-20, 03:12 PM
#70
We all know the time in the past when toyota went to 10k miles OCI and people had sludge in the engine. Design problem, nevertheless, the remedy was to use synthetic oil and change oil sooner. After problems with sludge, toyota lowered OCI back to 5k in newer models, and in 2013 and up they went back to 10k OCI.
12-21-20, 03:43 PM
#71
Lead Lap
While I recognize that there are a number of posts in this thread that provide useful information, I can't help but notice that this thread has dragged on to 43+ posts when the answer to the question initially posed by the OP could have been answered by spending about 2 minutes with the owner's manual (and accepting what the manual said as true).
12-21-20, 04:22 PM
#73
12-21-20, 06:08 PM
#74
Instructor
Thread Starter
To clarify a couple things on when 5k and 10k service can be done free of charge. Per my Service Mgr who I've dealt w for long time--- Lexus Corp will honor the 5k service up to 9 mos out when veh was put on the road. For 10k service they will honor up to 18 mos out when veh was purchased n put on the road. So for my Dec 2019 purchase of 20 ES FSport, I waited till rt b4 9 mos out to go in for 5k service. Veh is 1 yr old this week n has 4500 miles. Will take it in b4 June 16 2021 to do 10k oil change and have done free of charge per Lexus Corp guidelines. Hope that helps others who put low miles on their Lexus n don't want to go in too early for these services.
JREY
JREY
At 17 months, I made it by a month. Although with the pandemic, I suspect that the dealers may give some leeway on this limit.
12-22-20, 01:29 AM
#75