Layer of sludge.

[The motor guy]

So I've noticed an interesting observation with my one gallon oil jugs I use to store my used oil. I keep about 15 of them that are constantly reused then bring them to the autoparts store when they're full 5 at a time because that's all that's allowed. Some of these will sit for a year or so, but there always seems to be a big 1in layer of sludge at the bottom that oozes out compared to the rest of the oil in the jug that flows out normally. So I guess if you live in an area where you're engine goes unused for months at a time I'd give it a fresh oil change before layup.

 

[Kira]

An oil change has been on every "pre-storage" check list I've ever seen.

Crank up the tire pressure....block the vehicle's weight off the springs....top up the fuel (check that one for modern times)...give her a wash....disconnect/remove/write off the battery (depending on circumstances)....treat the vinyl roof (ha-ha)....

 

[Donald]

I am not sure its a valid comparison. Leaving a car sit for a few months with oil that is not at its end-of-life should be fine. But if it needs changing I would change it before letting it sit.

 

[BMWTurboDzl]

Probably just solids settling out of suspension.

 

[wpod]

It is carbon and other crud from the combustion process , dirt in the air and degraded oil stuff .

 

[Kjmack]

It is carbon and other crud from the combustion process , dirt in the air and degraded oil stuff .

That's why 10k oci is nuts

 

[tmorris1]

I agree. That is also the reason that you run the engine to get that crap into suspension and warm up the oil before you change it.

 

[BMWTurboDzl]

That's why 10k oci is nuts

Why is it nuts if the material is held in suspension and not causing any problems?

 

[nwjones18]

I've noticed the same thing in my old jugs that I reuse over and over again for dumping. I don't notice it the first time or two I use a jug though. It takes multiple refills to get the sludge layer on the bottom. I figured it was because of all the different oils I end up mixing in them over time... Interesting thought though.

 

[Kjmack]

Why is it nuts if the material is held in suspension and not causing any problems?

Hasn't it been proven that carbon is hard on timing chains ? So a 10k oci would have 2x as much carbon as a 5k oci . I really don't care what a TBN says . That's just saying it has some level of active add pack left .
Yeah oil is better than it's ever been , but today's engines are harder on it then ever also , turbos , gdi etc .

 

[BMWTurboDzl]

Hasn't it been proven that carbon is hard on timing chains ? So a 10k oci would have 2x as much carbon as a 5k oci . I really don't care what a TBN says . That's just saying it has some level of active add pack left .
Yeah oil is better than it's ever been , but today's engines are harder on it then ever also , turbos , gdi etc .

Yes but that doesn't mean that at 10k miles there's too much carbon in the oil. Perhaps it's at 13k or15k miles?

You do know that there's 2x the carbon at 5k miles compared to 2.5k miles.

 

[Kjmack]

Yes but that doesn't mean that at 10k miles there's too much carbon in the oil. Perhaps it's at 13k or15k miles?

You do know that there's 2x the carbon at 5k miles compared to 2.5k miles.

Now you're being ridiculous, I quit 1500 mile oil changes a long time ago

 

[joekingcorvette]

It sounds to me as if the bad stuff settles to the bottom of the jug. I know if I spill a little oil on my driveway when changing oil it cleans up very easily. My moms 1999 Buick leaked oil in my driveway from a bad oil pressure switch/sensor and even though it had clean oil in the engine it created a dark stain on the driveway that would pressure wash off. Her car has some sludge in it too from short trips and infrequent changes. I definitely believe in frequent oil changes.

 

[philipp10]

So the OP has reused the same jug for multiple oil changes and it built up crud in the bottom, over many years of use. From there, the OP came to the conclusion that used motor oil is sludgy and full of contaminants (and said contaminants are bad). That's quite a leap. First off no one knows if those are contaminants or additives. Secondly, even if there are contaminants, no one knows if they are a problem. Just saying.

 

[BMWTurboDzl]

So the OP has reused the same jug for multiple oil changes and it built up crud in the bottom, over many years of use. From there, the OP came to the conclusion that used motor oil is sludgy and full of contaminants (and said contaminants are bad). That's quite a leap. First off no one knows if those are contaminants or additives. Secondly, even if there are contaminants, no one knows if they are a problem. Just saying.

Exactly.

 

[DGXR]

I have the same layer of sludge at the bottom of my used oil jugs, just a minor annoyance. I try to remember to shake them up a bit before handing them to the parts store people who dump them for me.