Do I really need to change my oil, less than 500 miles in 2.5 years?

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27,516
Location
PNW
If the oil and filter only had 1 year and 500 miles on it, I'd probably go another year if the car isn't short tripped. But you have ~3 years on it now, so I'd change it.
 
Messages
1,228
Location
ottawa
A UOA costs more and takes longer than just changing the oil out, and a UOA does not resolve the ultimate issue that there's oil in the car for an exceptionally long period of time.

I don't understand the UOA advice at all. Sure it's some data, but it doesn't address the known problem nor provide a solution.

If your house was on fire, you're not going to get a thermometer to gauge how hot the fire is. You get suppression to stop the fire. Same thing.
The point of the UOA is to gauge the condition of the oil over the 2.5 years. It may cost some upfront but it may also safe the OP money by not changing the oil too early as per his application.

Also your analogy does not makes sense at all - - we are talking apples and you are talking boats? House fire?
 
Messages
1,228
Location
ottawa
A sweet car like a Supra turbo with almost three year old oil? Pony up the 20-something bonz and CHANGE THE OIL!!(y)

"When in doubt, change it out":D
Agreed -- - - that is a VERY RARE and sought after car - - VERY.
There was an article in last months car and driver about appreciation and specific models - - that supra was on the top by a wide margin.
 
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16,043
Location
N.H, U.S.A.
I have a 1994 Toyota Supra turbo that I keep garage and hardly ever use it.

I replaced the oil in 8/2018.

Do I really need to change it if it has less than 500 miles on the oil?
Absolutely not.
This biggest worry would be filter degradation from water form short starts to move it around without warmup.
The oil will be fine.

Whats the plan for the car? If you waiting for it to appreciate - I would sell it this Spring before all the extra
pocket change disappears. I you are very wealthy, you can hang on to it.
 
Messages
517
Location
KY, USA
I'm not familiar with the OCI on turbo engines. I've got a '97 Ford with 41K miles that stays in the garage 99% of the time. I change the conventional oil /filter in it at 5K mile intervals regardless of elapsed time. Until 30K miles I changed oil/filter every 3K miles regardless of elapsed time. This is a 24 year old car that's had 12 oil changes since new so average OCI has been 2 years. 99% of the time when I drive it it's being driven far enough to get the engine to full operating temperature so I know there shouldn't be any problems with moisture. I think it's been at least 2-3 years since the oil was changed in it and it's been right at 2K miles since it's last oil change and about 1K miles of that was on a road trip from KY-NC and back soon after it's last oil change. If your car is short tripped a lot changing the oil a little early wouldn't hurt anything but if it were mine at 500 miles it would stay in probably till at least 2.5-3K miles. I'm pretty sure there have been times oil/filter have stayed in my Ford for at least 5 years and I've seen no negative effects from doing so. When I bought the Ford brand new it was bought in '98 so it was a one year old car at that time. I'm sure the dealer hadn't changed the oil in it even though it was a year old and had 50 miles on the odometer when I bought it
 
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Messages
189
Location
USA
I'm not familiar with the OCI on turbo engines. I've got a '97 Ford with 41K miles that stays in the garage 99% of the time. I change the conventional oil /filter in it at 5K mile intervals regardless of elapsed time. Until 30K miles I changed oil/filter every 3K miles regardless of elapsed time. This is a 24 year old car that's had 12 oil changes since new so average OCI has been 2 years. 99% of the time when I drive it it's being driven far enough to get the engine to full operating temperature so I know there shouldn't be any problems with moisture. I think it's been at least 2-3 years since the oil was changed in it and it's been right at 2K miles since it's last oil change and about 1K miles of that was on a road trip from KY-NC and back soon after it's last oil change. If your car is short tripped a lot changing the oil a little early wouldn't hurt anything but if it were mine at 500 miles it would stay in probably till at least 2.5-3K miles. I'm pretty sure there have been times oil/filter have stayed in my Ford for at least 5 years and I've seen no negative effects from doing so. When I bought the Ford brand new it was bought in '98 so it was a one year old car at that time. I'm sure the dealer hadn't changed the oil in it even though it was a year old and had 50 miles on the odometer when I bought it
Well you've taken a big risk against oil makers recommendations to save a whopping ~$400 over 35 years...
 
Messages
189
Location
USA
The point of the UOA is to gauge the condition of the oil over the 2.5 years. It may cost some upfront but it may also safe the OP money by not changing the oil too early as per his application.

Also your analogy does not makes sense at all - - we are talking apples and you are talking boats? House fire?
It's been too long. The current condition is literally irrelevant, and not worth spending twice the price of a change with known new oil/filter to find out it might be okay. Simple math and problem solving here.
 
Messages
1,228
Location
ottawa
It's been too long. The current condition is literally irrelevant, and not worth spending twice the price of a change with known new oil/filter to find out it might be okay. Simple math and problem solving here.
Too each is own.....
Agree to disagree.
I see value in a UOA if the OP plans to stretch their OCI during future use.
 
Messages
517
Location
KY, USA
Well you've taken a big risk against oil makers recommendations to save a whopping ~$400 over 35 years...
I don't know where you come up 35 years. 2021-1997=24. It's not about saving a few dollars on oil changes, I just refuse to discard good oil. The oil I'm using when I do my oil changes has been in the garage for 15-25 years depending on which car I'm changing oil in and which brand oil I'm using. What's the difference in the oil sitting on a shelf in the manufacturers plastic bottle or sitting in the oil pan of my car? The oil I'm using in the Ford is oil that I had in the garage when I bought the car new in 1998. When I do an oil change if I think about it I'll give the bottle a few shakes before pouring it in, if I forget I don't worry about it it's going to get well mixed when the engine is started. I really don't recall how long I'd had the oil when I bought the car. Years ago I had an oil burner/leaker that I used as a work car. It was going through about a quart every 300-500 miles. I quit changing oil in it and was pouring oil back into it that I drained out of my good cars at oil change time. When I sold the car it had been 31K miles since it's last oil change. Oil consumption was no worse and there was no knocking in the engine when I got rid of it. I know the guy that bought it from me drove it at least another 1-2 years before scrapping it because it wouldn't pass emissions testing since the catalytic converter had been taken off of it years before.

In the early to mid '00's I bought about 10 cases of Pennzoil yellow bottle at a flea market that was bottled in the '80's. I ran it in two different cars. One of them was retired arouond 2011-2012 with 518K miles not because the engine gave up but because it needed work done to it that I didn't feel like doing and I wasn't paying someone $50-100 an hour to work on a car with 1/2 million miles. The other is still going strong approximately 100K miles later at 209K and uses less than a quart between 5K mile intervals.
 
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Messages
189
Location
USA
Yes, I either did the math wrong or hit a 3 instead of a 2. The fact remains, old oil sitting in a car is harmful.

True, oil in a seal container on a shelf probably does last decades and probably as good after 20 years or more as it was when packaged. It's not reacting with other elements or compounds, other than perhaps plastic containers.

The problem is when it is put into a motor, it is subjected to heat, fuel, oxygen, and so forth, and as I understand it old oil can get acidic. There's negative chemical reactions occurring, especially with MOISTURE which will destroy a motor. I had a totally sealed lawn mower that I was lazy and put a tarp over. Moisture got in the oil and turned it to milk and destroyed a nice mower.

Also, let's not forget about the really really old oil still in the block. Most cars leave about 1/2 quart of old oil in the block during every change. The fresh oil just dilutes it, about 10 to 1 depending on size and design. IOW, about 10% of your old oil from prior changes remains in that motor.

Let's say your vehicle leaves 10% of the oil in the block upon every change and a change is 6 quarts, leaving 0.6 old oil quarts inside each change. You change your filter & oil each time, say every 5 years in 2000, 2005, 2010, 2015, and 2020. New changes dilute the old oil by 90%. So by 2020 you've still changing out a fraction of a quart of 20 year old oil from 2000... Another reason why frequent or at least annual changes are good is to continually flush that remaining 10% of ancient oil out of the system thru dilution.
 
Messages
27
Location
SC
Most motor oil can sit on the shelf for 3 to 5 years per most manufacturers. I don't blame you for not changing it with 500 miles on it.

While it is probably okay, I would just change it; besides, you would be upgrading to some API SP from presumably API-SN oil anyway.
 
Messages
252
Location
Port Aransas, TX
This may be of interest because of the length of time the oil was used. 3 years 3 months. 1999 Mercedes SLK230 Supercharged. Car has an oil countdown gauge that starts a 10,000 miles. it still said I had about 6k miles left before change at 5k miles on the oil. then at approximately 3 years it read zero all of a sudden. which means it's time to change. I changed it about 400 miles later which said I was 400 miles overdue. Anyway, it looks to me that the recommended oil change is 10k or 3 years. Holds 6 qts. Car was usually driven on nice sunny days with the top down. 35% to work stop and go traffic 10 miles, 30% long trips, and 35% just short pleasure drives and running errands. Driving style. Mostly normal, but I do love to kick in that supercharger quite a bit. I was pleased by the report with what I feel are low metal wear. I would always give it an Italian tune every couple of weeks to get the oil up to a good temp to evaporate any condensation. Now my newer 2013 SLK250 has a turbocharger. It is very hard on the oil and I guess the turbocharger breaks down the viscosity. I have done a few oil analysis on this newer car and change every 4500 miles.
 

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Messages
517
Location
KY, USA
Yes, I either did the math wrong or hit a 3 instead of a 2. The fact remains, old oil sitting in a car is harmful.

True, oil in a seal container on a shelf probably does last decades and probably as good after 20 years or more as it was when packaged. It's not reacting with other elements or compounds, other than perhaps plastic containers.

The problem is when it is put into a motor, it is subjected to heat, fuel, oxygen, and so forth, and as I understand it old oil can get acidic. There's negative chemical reactions occurring, especially with MOISTURE which will destroy a motor. I had a totally sealed lawn mower that I was lazy and put a tarp over. Moisture got in the oil and turned it to milk and destroyed a nice mower.

Also, let's not forget about the really really old oil still in the block. Most cars leave about 1/2 quart of old oil in the block during every change. The fresh oil just dilutes it, about 10 to 1 depending on size and design. IOW, about 10% of your old oil from prior changes remains in that motor.

Let's say your vehicle leaves 10% of the oil in the block upon every change and a change is 6 quarts, leaving 0.6 old oil quarts inside each change. You change your filter & oil each time, say every 5 years in 2000, 2005, 2010, 2015, and 2020. New changes dilute the old oil by 90%. So by 2020 you've still changing out a fraction of a quart of 20 year old oil from 2000... Another reason why frequent or at least annual changes are good is to continually flush that remaining 10% of ancient oil out of the system thru dilution.
Using your thoughts about a fraction of quart of oil remaining in the engine being an issue why it that every automatic transmission on the road isn't worn out? Most cars drain less than 50% of the fluid when doing a drain/fill because on most there's no way to drain the torque converter. There are also lots of people who never change the transmission fluid and drive 200K+ miles. Years ago lots of manufacturers recommended only changing the oil filter every other drain interval and at the time even large V8's only had a 5 quart capacity and lots of the filters in those days held close to a quart of oil. Using your analysis this would have been leaving about 1.5 quarts of old oil in every other oil change. This was also in the days of carburetors where fuel dilution was more of an issue than it is today. When my dad bought a new Mercury in 1968 Ford recommended 6K mile OCI's with filter every other oil change. When I bought a new Buick in 1977 GM recommended 7500 mile intervals and if I recall correctly filter every other OC. Today with supposedly better oils/filters some manufacturers still recommend 5K mile OC. Now days lots of V8's have a capacity of 6-8 quarts and some maybe even more. I don't deny there's some oil left in the engine at oil change but sometimes when I know I'm going to be changing oil the next morning I'll pull my car on the ramps the night before so the oil has had all night to drain to the pan and all the oil except what's clinging to the sides of the pan runs to the back of the pan where the drain plug is so very little oil is left behind.
 
Messages
7,058
Location
Wet side WA
Using your thoughts about a fraction of quart of oil remaining in the engine being an issue why it that every automatic transmission on the road isn't worn out? Most cars drain less than 50% of the fluid when doing a drain/fill because on most there's no way to drain the torque converter. There are also lots of people who never change the transmission fluid and drive 200K+ miles. Years ago lots of manufacturers recommended only changing the oil filter every other drain interval and at the time even large V8's only had a 5 quart capacity and lots of the filters in those days held close to a quart of oil. Using your analysis this would have been leaving about 1.5 quarts of old oil in every other oil change. This was also in the days of carburetors where fuel dilution was more of an issue than it is today. When my dad bought a new Mercury in 1968 Ford recommended 6K mile OCI's with filter every other oil change. When I bought a new Buick in 1977 GM recommended 7500 mile intervals and if I recall correctly filter every other OC. Today with supposedly better oils/filters some manufacturers still recommend 5K mile OC. Now days lots of V8's have a capacity of 6-8 quarts and some maybe even more. I don't deny there's some oil left in the engine at oil change but sometimes when I know I'm going to be changing oil the next morning I'll pull my car on the ramps the night before so the oil has had all night to drain to the pan and all the oil except what's clinging to the sides of the pan runs to the back of the pan where the drain plug is so very little oil is left behind.
Well the very big thing is a Transmission isn't dealing with the carbon the internals of your engine are!
 
Messages
517
Location
KY, USA
Well the very big thing is a Transmission isn't dealing with the carbon the internals of your engine are!
True, but heat is the main detrimental factor with transmissions and ATF so replacing 50% or less of the fluid would mean the fluid is 50% worn out as soon as you finish the drain/fill yet most if any manufacturers don't recommend doing the next change 50% sooner. Nissan says the fluid in my '16 Versa CVT is lifetime but with the number of failures they've had with their CVT's over the past 20 years I'm changing it every 30K miles and at 90K I'll probably do 2 or 3 drain/fills within the next 10K and restart the process at 100K. The fluid does degrade. I used to have a '76 Chrysler that every couple years the transmission would start not going into gear as soon as shifted to drive. The torque converter on it DID have a drain plug I'd replace 14 quarts and the filter every couple years which equated to roughly every 30-40K miles then it would be good for another couple years.
 
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