how long do you store motor oil ?

[rusty ol ranger]

Pour it in, if it starts knocking drain it and buy new.

Just kidding.

 

[Bgunner]

Motor oil isn't hygroscopic or hydrophilic. It won't absorb moisture from the air or mix with it. Moisture could condense and collect inside of an open bottle, but it isn't going to mix with the oil. It's going to do its best to separate from water. If any water collected in a bottle of oil, it'll be in the bottom with the oil riding on top. The only reason water mixes with oil in the crank case is the blending action of the crankshaft. That's why you end up with a milkshake when a head gasket blows, air and water in the cranks case bets blended into the oil creating the milky appearance.

Brake fluid (at least the stuff used in Rangers) on the other hand is hygroscopic. It'll absorb moisture out of the air in a heart beat. That's why they tell you to not use a previously opened bottle of brake fluid. The added water content will lower the boiling point and mess up braking performance.

The issue with oil in the engine getting water is from condensation not that it really absorbs water from the air like brake fluid. There is so much more surface area in an engine filled with air than what is in a bottle. In my case only driving a few thousand miles a year, last year it only drove just over 1,300 miles, the engine sits a lot and doesn't run much giving it a better chance to get condensation than a vehicle that drives 15,000 a year.

 

[Shran]

I have some like that. I use it for cutting oil when drilling metal. Or little jobs, as mentioned, like door hinges, casters, etc.

Oil is expensive. My Superduty and motorcycle can both use Rotella T6 15w40 synthetic. I think I’ll start using the same in the Ranger. Found I can buy 5 gallon buckets of it from Wal-Mart for $100. That’s just $5 per quart. Northern sells a hand pump for the 5 gallon buckets. So, I’ll just consolidate to one oil for everything.

I use it in my air compressors and lawn equipment. That's about the only place that calls for 30w non detergent these days. I dumped it into one 5 gallon bucket because some of the cans started leaking... weird stuff, it's very dark brown.

Some of my vehicles have not had the oil changed in years. Just don't drive them enough. The F150 I think was last changed in 2019. I use old oil from yard sales & stuff all the time. Never had bit me.

 

[JoshT]

The issue with oil in the engine getting water is from condensation not that it really absorbs water from the air like brake fluid. There is so much more surface area in an engine filled with air than what is in a bottle. In my case only driving a few thousand miles a year, last year it only drove just over 1,300 miles, the engine sits a lot and doesn't run much giving it a better chance to get condensation than a vehicle that drives 15,000 a year.

First off, reread that post and what I was replying to. It was in regards to another member expressing concern that oil in an opened container(a bottle/jug) would absorb water out of the air.

Second, you say it sits long and doesn't get run much. Time sitting doesn't matter as much as time running. When it runs, how much does it run?

Yes, as the engine cools, moisture that is in the air inside the engine will condense inside the block. That isn't a lot of moisture though. While the engine is stopped you aren't getting much, if any, air fresh moving through there. Once the moisture is condensed and the engine is cool, that's it until the next heat cycle of the engine and fresh air is pulled into the crank case. If you drive it for a meaningful amount each time the oil will reach operating temperature which exceeds the boiling point of water. The moisture in the crank case will burn off (boil or vaporize) and get extracted via the PCV system before the next cycle.

Problem for typical lower mileage engines is that they get run frequently for short periods. They are started and driven for short distances so the engine gets warm enough that it causes condensation when it cools. The engine is never run long enough to fully warm up and burn off the moisture that collected from the previous drive. Because it happens frequently, two or more times a day, the condensation has a chance to build up.

 

[JoshT]

Oil is expensive. My Superduty and motorcycle can both use Rotella T6 15w40 synthetic. I think I’ll start using the same in the Ranger. Found I can buy 5 gallon buckets of it from Wal-Mart for $100. That’s just $5 per quart. Northern sells a hand pump for the 5 gallon buckets. So, I’ll just consolidate to one oil for everything.

Sounds like a good idea. I use the same stuff in the F-250, but I bought the 2.5 gallon jugs. Stuff ain't cheap, but I also won't be changing it that often.

Still got a motorcycle, but haven't touched it in almost a decade and don't recall what it uses for oil. Next time it gets changed it's getting sold, so will probably use the cheapest thing that meets specifications.

I don't know that I want to change my other vehicles to 15w40. Think that might be a little too thick for the Ranger or Forte, and too thin for the F-100. The latter is running Valvoline VR1 for the ZDDP, 20w50 IIRC to get good oil pressure for to the wear. The FE were never great on oiling and it's overdue for a rebuild.

 

[JoshT]

Some of my vehicles have not had the oil changed in years. Just don't drive them enough. The F150 I think was last changed in 2019. I use old oil from yard sales & stuff all the time. Never had bit me.

That's the position I'm in with my F-100 and F-250. That's also why I use synthetic in them. Figure it'll hold up a little longer than conventional.

 

[Curious Hound]

I don't know that I want to change my other vehicles to 15w40. Think that might be a little too thick for the Ranger

I'll take my chances on it in an old worn out 3.0l. It'll be like using "high mileage" oil.

 

[JoshT]

It'll be like using "high mileage" oil.

Not really. High mileage oils allegedly contain a larger addative load. More detergents and conditioners. Things that would be "needed" for cleaning and sealing an older engine.

The 15w40 on the other hand is just a thicker viscosity. It's not necessarily going to have the additives, but it would fill the bearing gaps in a worn engine better.

It may be that the latter is what your 3.0L needs. I know it's what my old FE needed.

 

[Bill]

Motor oil isn't hygroscopic or hydrophilic. It won't absorb moisture from the air or mix with it. Moisture could condense and collect inside of an open bottle, but it isn't going to mix with the oil.

It can absorb moisture due to the additives. I was taught that this moisture accelerates the breakdown of the additives in the oil. However, that was in the 80s when the additives were mostly detergents.

 

[Bgunner]

It can absorb moisture due to the additives. I was taught that this moisture accelerates the breakdown of the additives in the oil. However, that was in the 80s when the additives were mostly detergents.

Interesting. I hadn't considered if the additives used could absorb water.

 

[JoshT]

Oil additive package makes up about 20% of volume. Part, likely not all, of that package may absorb water. I'm not convinced on that and it would depend on the manufacturer's additive package. Still you aren't talking about much there and it does not change what I previously said.