Oil blackening.... What does it early?

[shady]

95 6.5TD...
I changed the oil and noticed the next morning when I rechecked the level that it was black again. So changed it again a couple days later.

And this is less than 100 miles into that oil change.

Is that common with these? I've had a 6.2 before but don't recall it turning the oil black this fast.

 

[diesel4me]

My 6.2 turns the oil black after an oil change after one ride ..
My VW Jetta diesel did the same thing..

It's not a sign of anything "wrong",it is just the high detergent level in diesel rated oils doing its job,keeping soot and dirt in suspension..

I have used some oil not diesel rated in my diesels before and noted they remained "clean" looking on the dipstick,that was something I didn't do for long because it can let soot build up on everything and cause problems..

 

[Bent77]

Part maybe there was some (enough) residual in the engine, that it discolored the clean oil

As Bob said, it’s pretty normal, as long it doesn’t smell like fuel

 

[ktmoutfront]

That is just the inside of the engine being dirty from running it. Gas engines will do the same thing, just not as quickly.

I did an oil change on a lawn mower for a guy. He complained that after mowing once the oil was black. Accused me of not changing it. He brought it back and watched me change it again. I started it and let it run for ten minutes. Showed him the oil. He paid me the $100 I told him it would cost to prove it to him.

 

[Smokinthehippies]

Diesels do it. All diesels do it. All my dodges do it so did my 6.5. I have no clue why. Except they’re filthy shits.

 

[shady]

I kind of figured it was normal, and did expect some residual, but just figured I'd ask.. thanks guys

 

[shady]

I knew they all made the oil black, and need changed more often. But in such a short time seemed odd lol.

 

[TreeFarm]

I wouldn’t say they need to be changed more often. Low rpm/stress and high quantity of oil keeps it lasting just fine.

like said before, it’s just combustion gasses and soot getting around the rings. High compression ratios mixed with boost will do that. Especially if you start adding more fuel.

biggest thing is to make sure you’re not gaining or losing oil. You don’t want that oil leaking our, or the crank case filling with water or fuel depending on the engine.

 

[Wes Harden]

You shouldn't go by color alone, time plus amount and type of use.
Engine needs to get warm regularly, to evap moisture. Also how dirty is the environment is operating. Oil doesn't go bad it gets dirty. If you had a Frantz type bypass filter and changed that filter let say every 1000 miles, top off with clean oil, you would never need to change oil.

Use Scott's single ply

 

[Smokinthehippies]

You shouldn't go by color alone, time plus amount and type of use.
Engine needs to get warm regularly, to evap moisture. Also how dirty is the environment is operating. Oil doesn't go bad it gets dirty. If you had a Frantz type bypass filter and changed that filter let say every 1000 miles, top off with clean oil, you would never need to change oil.

Use Scott's single ply

Yup. You can send oil sample in for testing too if you get real froggy with it. I just change mine once a year in my dodge

 

[campfire]

In addition to the above posts, the oil cooler retains a charge of old oil which will mix back in as the engine runs.

 

[campfire]

You shouldn't go by color alone, time plus amount and type of use.
Engine needs to get warm regularly, to evap moisture. Also how dirty is the environment is operating. Oil doesn't go bad it gets dirty. If you had a Frantz type bypass filter and changed that filter let say every 1000 miles, top off with clean oil, you would never need to change oil.

Use Scott's single ply

I have an oil centrifuge lying around for exactly that purpose.

Never did get around to installing it. Hmm...

 

[shady]

I wouldn’t say they need to be changed more often. Low rpm/stress and high quantity of oil keeps it lasting just fine.

like said before, it’s just combustion gasses and soot getting around the rings. High compression ratios mixed with boost will do that. Especially if you start adding more fuel.

biggest thing is to make sure you’re not gaining or losing oil. You don’t want that oil leaking our, or the crank case filling with water or fuel depending on the engine.

Dad just always told me a diesel needed to maintain the 3000 mile change close, and he said a gas engine was more forgiving.

You shouldn't go by color alone, time plus amount and type of use.
Engine needs to get warm regularly, to evap moisture. Also how dirty is the environment is operating. Oil doesn't go bad it gets dirty. If you had a Frantz type bypass filter and changed that filter let say every 1000 miles, top off with clean oil, you would never need to change oil.

Use Scott's single ply

I was basically hoping someone didn't say "Dude that's fast, your rings are SHOT" lol. I know the oils new, but wanted to make sure I wasn't baking it or something.

In addition to the above posts, the oil cooler retains a charge of old oil which will mix back in as the engine runs.

That was why I changed it the second time right away, just to try and flush stuff like that.

 

[TreeFarm]

3k miles is excessive in my opinion, but that’s just me. Oil has come a long way since the 70s. For example dodge/Cummins recommends that only for severe duty on an 89-98 6bt. With regular duty being 5k. 24v is bumped your to 7.5k, and common rail bumped to 15k miles. I personally run 7.5k with cheap Dino oil (rotella) on every diesel I’ve owned, but I’m not religious. If I go over or less I know it’s fine. Regular means regular, not exact. I am religious about checking the level though. A bad injector can’t quickly fill that oil with fuel or a bad cooler/head/block will fill it with water. Both will quickly ruin an engine.

Ill be switching to synthetic for winter use from now on though. Waiting 45 seconds for oil pressure in winter got scary fast.

I guess you could argue for severe duty if you take a lot of short trips with low engine temps or tons of stop and go. I’m sure my exhaust break adds to some oil soot

 

[shady]

95% of the driving it sees is the 12.5 mile trip from home to work, then 12.5 back.

A little around town.

I use rotella. Tried to switch to the synthetic version with my old 6.2 and it quickly became way more noisy and did a lot of blue smoking.... On top of the oil leaks that got worse. Went back to normal and it was all good again.
I won't be going synthetic in this one lol

 

[campfire]

95% of the driving it sees is the 12.5 mile trip from home to work, then 12.5 back.

A little around town.

I use rotella. Tried to switch to the synthetic version with my old 6.2 and it quickly became way more noisy and did a lot of blue smoking.... On top of the oil leaks that got worse. Went back to normal and it was all good again.
I won't be going synthetic in this one lol

Was the synthetic oil of a lower viscosity?

 

[shady]

Sort of. Rotella around here comes in 2 versions. 15w40 dino juice, and 5w-40 synthetic.

Nobody in town here carrys anything but those 2.
Looking it up now I see that there is a 15w-40 full syn rotella

 

[shady]

On this one the PO said all he used was rotella and I liked that, so kept with it.

I'm afraid to change anything, because it's got 406k lol.


Speaking of changing things.... What would be a good interval for the inline screw on fuel filter he had mounted after the lift pump?

He gave me a box of filters with the truck

 

[campfire]

On this one the PO said all he used was rotella and I liked that, so kept with it.

I'm afraid to change anything, because it's got 406k lol.


Speaking of changing things.... What would be a good interval for the inline screw on fuel filter he had mounted after the lift pump?

He gave me a box of filters with the truck

Might depend how big the box is. I also have a uselessly big pile of filters lying around, so I could change mine annually. But realistically the filter should be changed when the output fuel pressure starts dropping. Which should take tens of thousands of miles. Unless you have sand in the fuel tank.

 

[diesel4me]

In addition to the above posts, the oil cooler retains a charge of old oil which will mix back in as the engine runs.

That is true..
But I deleted the oil cooler on my 6.2 and my VW never had one factory..just the oil left clinging to the engine's crankcase and pan will make the fresh oil turn black fast.

I change the oil in my 6.2 about every 3500 miles--if I remember right the owners manual states an even lower figure,especially in cold climates or your driving is mostly short trips..
My truck has only gone from 34,000 miles to almost 50,000 since I got it in 2003,so it sat a lot..
I feel oil is cheaper than engines so I try to keep it under 4000 miles between oil changes and it usually needs 1-2 qts added in the meantime,so I know the oil should still be "good"..

I haven't used synthetic in my diesels and wont,I see no advantage to them in a high mileage engine run on conventional oils all its life..it'd be a waste of money..
I've had more than one engine sound like it was going to blow after using synthetic too,but went back to "normal" with regular oil..
I feel if you want to run synthetic it should be done from new,not in an old engine with some wear..

As for the fuel filter,I have the big spin on one on the firewall..
I left the new looking WIX one on it that came with the truck ,which was just replaced ,but "ignored" it for 13 years,and I ended up stranded 15 miles away on the side of the road when a rough road with bad frost heaves "shook it up" hard enough to loosen the rust & crap at the bottom of the filter,and plugged it solid..
That stupidity cost me a $100 tow..

I now have an electric fuel pump added near the fuel tank,which requires a dinky Ford style gas filter on its input feed side,which might hold a teaspoon of dirt --I've been expecting that to plug up,but so far it hasn't...at least having one there,protects the pump,and prolongs the life of the larger spin on filter..

I do not have a secondary filter,there wasn't any when I got the truck--I figure the small filter at the pump,the sock in the tank,and the spin on one will filter the fuel enough not to cause any injector pump problems..