Oil Change Intervals Objectively

[Ron Texas]

Well op said short and long trips, so I assumed it isn't sitting 3 months at a time.

It never sits more than a month, and that might be once a year. There are lots of traffic lights where I live so a 5 mile round trip takes as long as a 20 mile round trip in the burbs. I'm going to give the oil a sniff and color check in a day or two.

 

[Doodski]

What a shame. I hesitate to generalize here, but the only woman that I have ever known to even remotely care about her vehicle was my mother. I know that is a gross generalization, but seriously, it isn't just with vehicles, the "general" trend I have noticed is for women to really care less about mechanical, or electronic stuff. It seems they just expect to buy, it bang it around and it should look after itself with no user intervention involved. I freely admit that my sample size for these observations is not massive, but it is greater than one!

I'm about the same. I knew the owner/manager of a outdoor equipment shop and she was into oil changes. Other than that vehicle maintenance was considered as a inconvenience by most all the women I've known too.

 

[Martin]

I change the oil on the manufacturer recommended interval or annually, whichever occurs first.

Martin

 

[RayDunzl]

Once a year, Mobil1 - now 0-16W in the Camry - more or less, kinda when I get around to it, since 1980.

Long ago I used to drain the bike and fill the Pinto with it.

 

[MRC01]

You have 2 options:
1. Follow the service guidelines in the car's manual and don't worry about it.
OR
2. When the oil is due to be changed, take a 3 oz. sample and send it in for analysis (called UOA for Used Oil Analysis). Decide whether to change it based on the results.

Option 2 is not necessary, but can be educational and fun for those who are curious about it. Or for those who put unusual duty cycles on their cars, like racing.

 

[TheWalkman]

On all my cars - including company cars- I always changed my oil at 5000 mile intervals (with an initial, “break-in“ change at 1000 - 1500 miles.) No longer.

On my latest purchase, I decided my days of German machines and the maintenance headaches are over so I bought a new Honda with a normally aspirated, four cylinder engine.

I decided not to worry about the, “best” intervals and instead, follow the maintenance intervals on the dash which is currently averaging 9 - 10K per change. (Yes, once upon a time, I’d visit Bob is the Oil Guy. No longer.)

I’m at 67K miles on this car and the engine runs as smooth as butter. I’ll use whatever synthetic oil is on sale and a decent quality oil filter - normally OEM or Pure One.

I‘m easy on my cars and not keeping my foot to the floor so my cars live a fairly easy life. No racing/ no commuting. No worries.

One less thing to think about.

 

[blueone]

People worry too much about engine oil. It is not like milk; it doesn't spoil. One year, 365 days, is not some magic length of time for synthetic oil's life span. As others have posted, the important thing is to occasionally, like at least monthly, take the vehicle out for a drive that gets the oil heated to full operating temperature for a good number of miles, like twenty, to boil off the moisture and other contaminants. Fifteen months, twenty months until you hit 5000 miles... I wouldn't and haven't changed the oil sooner. Anyone who thinks some audiophiles are prone to delusional behavior needs to hang around with long-time Porschephiles for awhile. The silliness is endless.

 

[Martini]

 

[blueone]

Oh jeez... LN Engineering. These guys sell a $26 oil pan drain plug.

https://www.pelicanparts.com/More_Info/LN90021900401LN.htm?pn=LN-90021900401LN&gclid=EAIaIQobChMI_5H9g_iP-AIV1XtvBB3SaglwEAQYAyABEgIrIfD_BwE

 

[G|force]

The 'one year rule' applies to the filter and the oil. If you are using a modern full synthetic Dexos labeled oil, (or Amsoil) those have been proven to get better with age in some engines. (Blackstone Labs)
7000 miles isn't always too much for modern oil. The oil filter can be, and sometimes is in need of replacement before the oil has expired.
Nobody changes a filter without changing the oil... But..Color and appearance has little to do with the condition of modern synthetic motor oil. Daily driven Turbo GDI here.

 

[Newman]

You haven't said what the car's manual says about oil change intervals?

As a low mileage driver you need to change the oil more frequently on a time basis, not less.

Whatever the objective oil science says, it is kind of irrelevant for one person and his individual car. For all you know your car is 'blowing' a little into the sump or oil cavities, which makes a huge difference.

So, unless you want to turn into Mr Mechanic and start investigating your car, either stick to the manual's time intervals or even increase the frequency a little as I suggested above. This is on the basis, that I suspect is true, that you actually want to spend less time and attention on your car, not turn into Mr Mechanic.

cheers

 

[Blumlein 88]

The 'one year rule' applies to the filter and the oil. If you are using a modern full synthetic Dexos labeled oil, (or Amsoil) those have been proven to get better with age in some engines. (Blackstone Labs)
7000 miles isn't always too much for modern oil. The oil filter can be, and sometimes is in need of replacement before the oil has expired.
Nobody changes a filter without changing the oil... But..Color and appearance has little to do with the condition of modern synthetic motor oil. Daily driven Turbo GDI here.

Actually, I've known a few people who changed the filter every 3000 miles and added the quart of oil that was left in the filter and nothing else. All espoused some version of oil not wearing out it just gets dirty, and a new filter cleans it up. That is not correct, but they believed it anyway. These people have gotten over 100,000 miles without engine issues and one fellow has a truck with about 225,000 miles he has done that way. The fellow with the truck is the only one using synthetic oil. I've wondered what the oil pan and top of the engines looked like inside.

I don't think it suggests this method being a good idea. I think it suggests modern engines and oils are awfully good. Along with maybe some of our concerns are overblown. If you are driving 2000 miles per year it takes 50 years to reach 100,000 miles. Maybe one method lets the engine last 150k and another more like 200k. But as long as you change the oil and filter on some halfway reasonable basis it isn't like one way ruins the engine in short order and another doesn't.

As for being an objective method, obviously oil analysis is the way to go. Everything else is assumptions and guesses based upon manufacturer's suggestions (which should be based upon some reality).

 

[G|force]

As others have mentioned in this thread, frequent short trips where the oil doesn't get hot enough for long enough is a concern.
My round trip to the local grocery market is 4 miles one way, but I usually drive past a few miles and turn around so the oil temp gauge needle is starting to rise some when I park.

I knew this female person in high school that got a new Toyota Celica hatch for her graduation present from her parents in 1985. 22R engine, 5 speed. Nice car.
In 1991 we reunited and shacked up, living together. One day when the same car now had 77,000 miles on it, I asked when was the last time the oil and filter was changed.
"I'll do it, I need to do mine too" I said.
This look came over her face and she said "I check the oil all the time, day before yesterday" We're talking no name $1.29 for a quart at the liquor store oil.
Needless to say, I removed the original OEM factory oil filter and changed the oil and filter, and a week later did it again.
That car always ran fine, it didn't know it was being abused. 20R and 22R are/were amazing engines.

 

[blueone]

Actually, I've known a few people who changed the filter every 3000 miles and added the quart of oil that was left in the filter and nothing else. All espoused some version of oil not wearing out it just gets dirty, and a new filter cleans it up. That is not correct, but they believed it anyway. These people have gotten over 100,000 miles without engine issues and one fellow has a truck with about 225,000 miles he has done that way. The fellow with the truck is the only one using synthetic oil. I've wondered what the oil pan and top of the engines looked like inside.

I don't think it suggests this method being a good idea. I think it suggests modern engines and oils are awfully good. Along with maybe some of our concerns are overblown. If you are driving 2000 miles per year it takes 50 years to reach 100,000 miles. Maybe one method lets the engine last 150k and another more like 200k. But as long as you change the oil and filter on some halfway reasonable basis it isn't like one way ruins the engine in short order and another doesn't.

As for being an objective method, obviously oil analysis is the way to go. Everything else is assumptions and guesses based upon manufacturer's suggestions (which should be based upon some reality).

Good comments. One more:

If the car is covered by a manufacturer's warranty, follow the manufacturer's maintenance recommendations, no matter how silly they are. For example, BMW and Porsche specify that you get at least annual oil changes, even for very low miles accrual. Since both of those manufacturers have had some very significant engine problems in their vehicles over the years, I strongly suggest just doing what they say. And dealer-performed changes are best for warranty-related questions.

 

[sam_adams]

Concerns about how oil is protecting your car's engine? Have it tested.

 

[JJB70]

It depends on engine condition and how the engine is used (little use, frequent short trips, lots of highway mileage etc etc), the safe default is to just follow the owners handbook, alternatively you can do oil condition monitoring (big engines don't change oil, the oil is conditioned and topped up but not changed) or just go by the seat of your pants and hope for the best. One thing I would say is that it's not very sensible to try and compensate for a knackered engine by pouring a bottle of new oil into the sump every week.

 

[thewas]

Even in such low mileage cars it depends also a lot on the engine type (indirect or direct injection, naturally aspired or turbo, petrol or diesel), the driving style (distances, load) and external conditions like temperature and humidity fluctuations during parking. It is not that a good modern oil really looses its slipperiness in a few years, but mainly due to combustion products acids are built up inside the engine that need to be neutralised by the oil. This can be measured with a recommendable oil analysis via the value of the TBN (total base number) which gets lower after some time and should always exceed the TAN (total acid number) otherwise some metals can be oxidised. A starting point that I used on my fun cars which have similarly low mileage and are robust naturally aspired indirect injection petrol engines is 2 years which is also usually the recommendable interval for brake fluid change (where I can recommend a not expensive water content measurement device).

 

[Bugal1998]

I have an ICE car which is driven about 2000 miles per year. Use is split between short and long trips in a warm climate. It came with synthetic blend oil but now runs full synthetic. Everything I could find says never go more than a year between oil changes without regard to mileage. However, I have been unable to find any objective data showing how much slipperiness the oil loses simply due to the passage of time. Is such objective information available or is the one-year interval something left over from the days before synthetic oil, a manufacturer's CYA or an old wives' tale?

As others have said, the only "objective" answer is oil analysis on the specific oil in your engine. It's not particularly cost prohibitive, but collecting the oil can be a pain if you're not equipped for it.

There are many reasons oil may need to be changed beyond 'slipperyness'; in fact loss of slipperyness in the commonly thought of sense is seldom ever a reason to change oil. For example, lookup TBN (Total Base Number) which protects the engine against corrosion, as a start.

 

[Trouble Maker]

I've got a car that I drive about that much per year, but it sits all winter, and it's a 'special'/expensive to replace engine so not apples-to-apples.

It's maybe an hour of my time, most of which is jacking the car up and crawling under it and cleanup. And even with OEM filter and a 'normal' full synthetic it's $50~$60/change. The Jeep Grand Cherokee Diesel daily driver is something like $100~$150/change. So $50 is cheap. Once per year in the spring when I pull it out of hibernation seems reasonable, even if it's probably not technically needed.

I put a Fumoto valve on it at this last change. I think it may allow me to change the oil without getting under the car, which would be amazing. This car is kind of a PITA to jack up with a regular car jack and stands. I can't wait for the new garage and lift we have planned, but can't seem to find the right contractor for.

I wanted to check for leaks before and after a few short drives, and I was able to reach through from above to all the way under the valve to take a picture.

So with a shorter oil drain pan it should be doable. I guess the actual oil change part might take 10~15 minutes after that. Going to the store for oil and cleanup will take longer.

The car is a Honda S2000.

 

[Doodski]

I watched a mechanic change the oil in a inboard boat. Because the V8 engine was tightly tucked in the boat the oil change was impossible from the bottom. So. The mechanic had a tool like a ~3 gallon canister with a vacuum pressure, with a long suction tube that fits inside the dipstick tube and he sucked the oil out the dipstick tube. It took a few minutes and then he just poured the new oil in and voila... done. It made things very easy.