oil is dark

Messages
70
Location
plano texas
My oil has been in there for about 400 miles adn I noticed its already somewhat darkened, is this normal. Also off topic, if I have a certain type of oil, in this case schaeffers 15w40, if I need to add a half quart or something can I add any oil like exxon superflo 10w30 dyno oil?
 
Messages
54
Location
Southern States
yes, you can mix it if you have to, it will not hurt your engine. I will however shorten the life of the oil as it can cause additive clash not allowing the oil to work as intended for extended drains and such. But, don't let the mixing issue concern you as for causing any mechanical damage as that will not be a problem.
 
Messages
47,692
Location
Duvall WA - Pacific NW USA
The darkening is probably from a cleaning effect. Mostly this is a good oil do a good job. Darkening can from ring blowby as well. Some cars can darken an oil really fast, while other cars other don't. What is the history of the car? Dark oil doesn't always mean shot oil - some diesels will darken the oil right away, but go many miles on the oil with no problem.
 
Pablo, Is the darkening oil just microscopic particles that are suspended in the oil? Everyone says not to judge oil by its color (which I somewhat understand) but doesn't it represent how many small particles are in the oil? I would imagine at some point the oil would not be able to suspend any more particles and it would need to be changed (as the oil gets to be black). I have a new vehicle (2003) that I have used M1 10W30 in it since I changed out the factory oil and it gets brown rather quickly.
 
Messages
18,449
Location
East of IGO
There are only so many companies that make oil additives. Additive clash is oil company marketing to fool us into not switching oil. Think about it zinc di bla bla that is used by one company is the same zinc di bla bla other brand uses also. just mix the same rated oils.
 
Messages
373
Location
Port Colborne, ON
quote:
Originally posted by Steve S: There are only so many companies that make oil additives. Additive clash is oil company marketing to fool us into not switching oil. Think about it zinc di bla bla that is used by one company is the same zinc di bla bla other brand uses also. just mix the same rated oils.
i don't think that's ... correct at all.
 
Messages
54
Location
Southern States
Actually Steve, mixing oils is not so uncommon very seldom would you find a problem with additive clash as you know it. Where the problem exists is that one oil has it blended in such a way that it can go further than some other sub grade oil, but when mixing different brands of oils, it will then create an unbalance of the additives therefore, you upset this balance and it may not perform as it was designed, thus the clash. consider like the additive problem shown on the front page of bobistheoilguy, where a good gear oil, blended with a special amount of antifoamant additive, then you take another oil, which is what lucas is, and put it into the blend, it will be compatible, and mix but it unbalanced the additives, thus makeing the original balance not work with the mix, causing excessive foaming.
 
Messages
1,759
Location
Elizabeth City NC
I have often wondered about this too. My toyota cressida the oil stays clear till about 3000 miles which is about where I change it. My 4cyl diesel boat engine the oil turns black as soon as you start it with new oil. My friends boat 4cyl diesel stays clear at least for 50-100 hours before turning. I think it is an indication of how well the oil is working. If the oil is doing its job it will turn black sooner. I know Mobil 1 turns black fairly quickly so it is cleaning quicker I guess.
 

Patman

Staff member
Messages
21,989
Location
Oakville, Ontario
I believe additive clash is more of a factor if you try to do extended intervals, such as if you change brands of oil and immediately try and go 15,000 miles. This should never be done. Always do a shorter interval (5k or so) on the first run, and then go with extended intervals later.
 
Messages
1,992
Location
Windsor,Ontario
I've noticed that if left to cool,like overnight,oil will be very dark.But if you check it after a good run on the highway it is much lighter in color...anybody else notice this?By the way it's Mobil SS that I'm refering to.
 
Messages
3,693
Location
Chattanooga, TN
quote:
Originally posted by Greaser: I've noticed that if left to cool,like overnight,oil will be very dark.But if you check it after a good run on the highway it is much lighter in color...anybody else notice this?By the way it's Mobil SS that I'm refering to.
This is true for all five of my vehicles using Amsoil. Especially after a few thousand miles.
 
Messages
612
Location
Joplin
quote:
Originally posted by Steve S: There are only so many companies that make oil additives. Additive clash is oil company marketing to fool us into not switching oil. Think about it zinc di bla bla that is used by one company is the same zinc di bla bla other brand uses also. just mix the same rated oils.
I'm told by someone in the industry that there are three major producers of oil additive "packages". Chevron, Lubrizol, and the third was a name I didn't recognize and have forgotten.
 
Messages
4,478
Location
Southern California
Diesel engine design considerations also play a BIG part in how soon the oil goes black. One school puts more emphasis on the piston rings controlling soot - outputting it into the exhaust. The newer emphasis is on intentionally allowing controlled extra blowby to carry soot into the crankcase where the soot is (hopefully) suspended by the detergent/dispersant package in the oil, itself. This results in less crap in the air, but dirtier looking engine oil sooner. One nice thing about diesels, though: you never have any trouble determining where the level is on the freakin' dipstick...
 
Messages
47,692
Location
Duvall WA - Pacific NW USA
I'm not a tribologist, nor organic chemist but I don't play one on TV either. (I do have a BS Chemistry but that was a long time ago and several careers back!) The optical/visual to human eye darkening of gas motor oil is not always from suspended particles (which is more common in diesels) - I think it's from some some soluble cleaning of left over residuals as well as chemical changes to the oil/add. package itself which render in less translucent, but don't immediately make the oil spent. Dr. Molecule probably has better detail on this. [ March 05, 2003, 07:27 AM: Message edited by: Pablo ]
 
Messages
901
Location
Northern Illinois
I have seen the difference in oil color between hot and cold also. I attributed it to the fact that a lot thicker coat of the cold oil clings to the dip stick so you are looking through a lot more oil. When hot it drains quickly down to a thin film that appears lighter in color. Or maybe not. [I dont know]
 
Messages
1,992
Location
Windsor,Ontario
The darker oil at cool down has to be a chemical reaction in the mix.I use to check my oil in the morning thinking this was best due to ALL the oil has drained into the pan and I will get an accurate reading.But the stuff was black at 3000 kilometers...so I changed it out early fearing contamination was going to ruin my engine.Now I check it after a 15-20 minute cool down after a long run...giving thermal exspansion, warm chemical reaction to the oil to give me a BETTER account of level and quality from my observation with my eye.This warm check of oil lets me run my Mobil to 7-8000 kilometers,and it STILL looks great...can see right thru the dipstick easily,and the oil is golden at that mileage.Before it was BLACK at cold check...now I'm saving a few bucks by not dumping my Mobil at 4000 km or 2,300 miles [Duh!]
 
Messages
6,388
Location
Washington St.
quote:
Originally posted by Cressida: ... I'm told by someone in the industry that there are three major producers of oil additive "packages". Chevron, Lubrizol, and the third was a name I didn't recognize and have forgotten.
Chevron-Oronite Lubrizol Ethyl Corp. Infinium (Royal/Dutch Shell & ExxonMobil) Ken
 
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