Do Not Leave Motor Oil In Motor Beyond 12Months

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The Manual for my 2019 Jeep states never leave engine oil in beyond 12 months. I’m assuming Chrysler states this because the oil gets caustic an can be detrimental to some internal engine parts even if you have not maxed out on the oil’s mileage rating. Is this assumption correct.
Thanks
 
The Manual for my 2019 Jeep states never leave engine oil in beyond 12 months. I’m assuming Chrysler states this because the oil gets caustic an can be detrimental to some internal engine parts even if you have not maxed out on the oil’s mileage rating. Is this assumption correct.
Thanks

That assumption is not correct. The 12 month jargon exists because of lawyers and people that never change their oil.
 
I've gone 2-3 yrs and everything is fine, just use a good full synthetic oil and the only time you should be worried about leaving it in for too long is warranty purposes.
 
I can't remember the last time I changed the oil in my S4. 2018 or 2019 maybe? Though I don't drive it and I barely start it.
 
It comes from those that really short trip their vehicles. It is very hard on the oil if it is only driven 2-3 miles, shut down for 6-8 hours, then driven 2-3 miles home, day after day.
You may only have 1500 miles on the oil in a year, but very hard miles.

Then you may have someone that drives their vehicle once a month, but drives it 100 miles on the highway. 1200 miles in a year, but the oil is just fine.

Auto manufacturers have to dumb it down to the lowest factor, so they just say xxxx miles or once a year.

My mom's Kia says 6 months max, which is a waste of oil. She drives maybe 2,000 miles in 6 months, with varied driving.
I save the oil from her vehicle for top off oil for my truck that has not had a change in 18 months (~3200 miles, uses a qt of oil every 1000 miles or so) and not sure when I will change it.
 
I have done 4 UOA's in 2 vehicles concerning intervals ranging from 18 to 30 months with 3 different oil types and none had any indication that time did anything to the oil except from the actual usage/distance. In fact my Honda CBR had 2 samples with the same type of driving (easy country roads) ,same distance (6000kms) and same oil (Motul 7100) but with 1,5 year interval vs 2,5 year interval.The TBN was 6,5 and 6,4 respectively.
 
Don't believe everything you read. I've run oil on occasion for well over 2 years, once or twice past three years in infrequently driven vehicles and UOA reports showed the oil was fine. The key imo is to take it for a long drive once in a while to burn off moisture and fuel. Having said that I might have to take a different approach if I owned a DI engine.
 
Does oil have an expiration date?
Someone posted a picture of the back of a Mobil container which stated to use the oil within five years of the "Made" date:


Oil Date.JPG
 
Someone posted a picture of the back of a Mobil container which stated to use the oil within five years of the "Made" date:


View attachment 78409
LOL, I worked at Kraft Foods once. All their use by dates were set in stone at two years at the time. Corporate policy and all. Miracle Whip is good for 5 years unopen before the cheap soy oil goes rancid.

Worked at a water bottler too and they used 2 years but it's because of the plastic leaching into the water. Might be the same for oil?
 
People love conspiracy theories but there is a rational and technical reason for the 12-month statement. It is because the automaker does not know how the vehicle is operated during the year, if it is extensively short-tripped (especially in cold weather) then it's quite possible that the oil may require changing in that year. If not then it can clearly go longer.

The oil does not get "caustic" in and of itself unless there are products of combustion to contribute to the TBN reduction. If you are not operating the vehicle during a time period the oil isn't going to go bad just sitting there. As long as the buffers in the oil aren't depleted (TBN at zero) then acids will be neutralized.
 
I think the 12 month guideline is a catch-all number that does have some good science behind it for some drivers. Every engine has caustic / acidic blow-by gasses. Some a lot and some practically none. Theses acid mix into the lubricant and do not necessarily all evaporate when the engine oil is hot.

Changing the oil once a year, or before it sits 3-4 months in the off season as many cars do, keeps the acidic oil from doing any damage to bearings.

A yearly oil change insures that the acidic buildup in the oil doesn’t reach a level that can do damage.

Z
 
I think it's prudent inexpensive measures to take for most drivers. If you're not changing it on miles, then a year is a good metric. The oil is exposed to short trips or infrequent driving presumably, and exposed to moisture that doesn't fully burn off at high operating temps, sludge, etc. And it's not that expensive particularly if it's just an oil drain and fill. Maybe $20-30 annually. Peanuts in cost, a few pennies per day for a year.

I do all my vehicles on time, and it's 6-12 months for all of them, some point therein when I have time and the weather is nice. A drain and fill or Mityvac extraction is pretty simple.
 
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