Oil color question - yet another!

[OilUzer]

some say oil color means nothing ... Meaning if it is dark or black it may/can still have some life. Is the opposite also true? Can an amber or dark amber or very very light brown color oil be bad since color means nothing? I have a newer v8 (MPFI) and the engine oil after 4000 miles is still very clear and amber with a very slight tint. At 2500 miles it looked like new oil. This car gets syn. Also have a very old v6 (MPFI) and at 4000 miles, the oil is very very light brown. Basically the color looks good. This car had 10Wx30 dino. Last time at 5K miles still looked very reasonable. Based on mileage , I was thinking about an oil change in this car but based on color I don't want to change it yet. Back to the original question, can you have an oil that looks good (color wise) but it's done (e.g. low tbn, way out of grade, etc.)? We always hear about used oil color means nothing ... But short of uoa, Can you generalize and say good color oil is always good but dark color oil may still be good?

 

[zeng]

Originally Posted by OilUzer

Can you generalize and say good color oil is always good but dark color oil may still be good?

Yes, for appropriate oil in use.

 

[Superflan]

Excessive fuel dilution can render the oil improper for engine protection, yet color will not change significantly

 

[RDY4WAR]

I see it a lot in drag racing where we run alcohol fuel with <180°F oil temps. After 25-30 passes, the oil will still be a dark amber, but have 3-4% fuel dilution. Also note that some ashless dispersants turn dark from UV exposure (from combustion events) making the oil appear black and oxidized when it actually isn't.

 

[cdlamb]

Originally Posted by zeng

Originally Posted by OilUzer

Can you generalize and say good color oil is always good but dark color oil may still be good?

Yes, for appropriate oil in use.

I wouldn't agree with this statement, without having done at least one oil analysis. If oil is consistently looking lighter colored at 4000 miles, and you are changing it at the same time, send a sample in for an analysis. Wear metals in PPM aren't visible to the human eye. It is possible that you may be able to run a 6000 mile interval, or possibly requires changing at 3000 miles! I would use a lab that does Gas Chromotography testing. I sent identical samples to Blackstone, & AGAT labs. Blackstone found 0% dilution, while GC testing said 3%. Viscosity results were different too, 54.2 / 8.55 at Blackstone, 47.5 / 9.0 AGAT Remember oil always looks lighter on the dipstick, than what it looks like in the drain pan. I recently purchased a used ATV, with only 300 miles. It was already 7 years old, the oil looked very good on the dipstick, but the seller couldn't say when (if) the oil was changed, as it was her husbands who had passed away. I changed it for peace of mind, & although looking like new oil on the dipstick, it ran pretty dark from the pan.

 

[T-Stick]

So while dark oil does not necessarily infer that it is depleted--most depleted oil will typically darken with time. A diesel (or even gas) engine that is letting a lot of combustion by products past the rings and into the oil, will typically turn oil black very quickly. I have used a series of short interval oil changes to clean up diesel (or even gas) engines and free their rings and as a result have cleaner/lighter looking oil for a much longer period of time. Most oil that turns black rather quickly is a result of the oil formulation (Amsoil turns dark quickly), or an engine that is getting combustion by products into the oil, or has sludge build up. Sludge and combustion by products are typically darker than fresh oil. If you are using an oil in a clean and mechanically sound engine that gets progressively darker till the end of its interval of usage--that could be an indicator of add pack depletion. Under these circumstances I do pay attention to oil color. If i use x oil in a newer clean/sound vehicle and it stays lighter to the end of its change interval and I use that same oil in an older less clean vehicle that was just purchased, I will typically run short oil change intervals until I can go the full distance on a recommended interval with the oil looking clean at the end of it's life cycle. That to me is a somewhat reliable indicator of having cleaned up the engine.

 

[PimTac]

Color means nothing. Period.

 

[T-Stick]

That statement cannot be substantiated. When an oil is typically clean looking and then it becomes frothy--that means something.

 

[Duffyjr]

Originally Posted by T-Stick

That statement cannot be substantiated. When an oil is typically clean looking and then it becomes frothy--that means something.

I have to ask what color is "frothy"? But I agree if you have air bubbles in your oil or dip stick something may be wrong.

 

[UncleDave]

Originally Posted by OilUzer

some say oil color means nothing ... Meaning if it is dark or black it may/can still have some life. Is the opposite also true? Can an amber or dark amber or very very light brown color oil be bad since color means nothing? I have a newer v8 (MPFI) and the engine oil after 4000 miles is still very clear and amber with a very slight tint. At 2500 miles it looked like new oil. This car gets syn. Also have a very old v6 (MPFI) and at 4000 miles, the oil is very very light brown. Basically, the color looks good. This car had 10Wx30 dino. Last time at 5K miles still looked very reasonable. Based on mileage , I was thinking about an oil change in this car but based on color I don't want to change it yet. Back to the original question, can you have an oil that looks good (color wise) but it's done (e.g. low tbn, way out of grade, etc.)? We always hear about used oil color means nothing ... But short of uoa, Can you generalize and say good color oil is always good but dark color oil may still be good?

Color itself with no other qualifying questions isn't much help. Color with a few other known variables - can mean a lot. You can "generally" say its good, but there are always qualifying bits of info to go along with mere color that assist in one's determination. There are instances where amber or clear oil may be hiding moisture, the oil may have sat a long time. One needs to know this info. In an MPFI system, there is a lower risk of fuel in the oil, but equal risk of moisture than may have condensed that won't show up on a stick pull. The whole bit of % of fuel in the oil isn't nearly the emergency its made out to be considering we had much more fuel in much lower quality oll in the 50, 60, and 70,s from poorly tuned carbs and we still got a very long life out of properly maintained vehicles. Id say if it's still gold, you run the engine at least semi-frequently getting it up to temp, and are showing no other signs of issues there is a high 90% probability you are just fine. Ask yourself if your mom came into a shop and her oil looked like this - can you really make a case it needs to be changed? Most people I know would call that a lube shop ripoff. If you bought this car off a car lot and the guy says its been maintained, but you didn't know anything about it would you drive it for a while and observe or go change it right away? UD

 

[T-Stick]

Originally Posted by Duffyjr

Originally Posted by T-Stick

That statement cannot be substantiated. When an oil is typically clean looking and then it becomes frothy--that means something.

I have to ask what color is "frothy"? But I agree if you have air bubbles in your oil or dip stick something may be wrong.

typically milky

 

[WobblyElvis]

This video is old but might shed some light.

 

[UncleDave]

This video always makes me laugh as the guy ends up referring to visual cues - he shakes the oil in the pyrex - and talks about it flowing, or not flowing well - by looking at it. You can see the dark oil sticking to the side of the pyrex when he swirls the bad samples. The question shouldn't be what can you tell by "color". The question should be can you tell anything about the state of oil using a number of visual, and olfactory clues, color only being one item on a list. UD

 

[DGXR]

Originally Posted by OilUzer

Back to the original question, can you have an oil that looks good (color wise) but it's done (e.g. low tbn, way out of grade, etc.)? We always hear about used oil color means nothing ... But short of uoa, Can you generalize and say good color oil is always good but dark color oil may still be good?

My $0.02 for what it's worth: Oil can look clean and "good" but still need changing. Others have referred to fuel dilution which is a good example of this situation. I was thinking of shear... some engines are harder on oil than others and will eventually shear a good oil out of grade but the oil may still look very good. Typically these engines have high-pressure oil injectors, oil cooling, lots of timing/balancing gears and chains, any combination thereof. They just beat up the oil more than the average engine. Oil can turn dark for many reasons: oxidation/age, buildup of soot, excessive heat/partial breakdown, etc. Dark oil does not necessarily need changing. The only way to tell if dark oil is still good is to send in a sample for analysis. I think lots of people change their oil based on color because an oil change is cheaper than analysis, and they still have to change their oil anyway. My Tacoma calls for 5k oci with dino. I have run it for 8000 miles on synthetic oil and I can still see through the oil when checking the dipstick -- it has serious color but still clear at 8000 miles, pretty good I would say. But when I drain that same oil, it looks super dark while draining and sitting in the pan, it's just nasty... but it still flows well and feels smooth and slick between my fingers. So I am not comfortable going over 8k on synthetic, in fact I might cut back to 7000-7500 on synthetic just for a safety margin. I just can't spring the money for an analysis when I can get 1.5 oil changes for the same money. P.S. I do use the blotter test around 5,000 and 7,000 miles just to see how things are going. The Tacoma starts getting "iffy" around 7,000 miles. The Corvette goes about 5k per year so I never worry much about that one.

 

[Loobit]

DGXR, I went in full limbo after reading your comment's last paragraph thinking it was a comment I made lol. I own a Tacoma and Corvette too and do the same oil change intervals.

 

[caprice_2nv]

Originally Posted by PimTac

Color means nothing. Period.

Wrong. We're not talking about diesels or direct injection or cars that get 15k mile oil changes. We're talking in general... And I don't care what you say, it does. I've done so many oil changes on neglected vehicles and we'll maintained vehicles and seen fuel dilution from a carb problem or whatever cause the oil to suddenly go black...I maintain that color is something you should pay attention to. Most people don't do uoa on their vehicles and short of doing that, looking at the dipstick is your best evidence of whether that vehicle has been maintained or not.