Basic question - why does oil get black so early?

[kr_bitog]

 Originally Posted By: jcwit

Have a '97 Geo Metro with almost 200,000 miles on it and the oil still stays amber till OCI at 5000 miles with Valvoline 10W/30 HM. I will say our new car doesn't get quite so dark but it has very little milage.

I believe the color change relative to the temperature exposed to the oil, so this varies for different engine. Any new Toyota VVT-i and Honda is known to have high temperature on certain parts of the engine, so it makes the oil getting dark very fast. Certain engine like this Geo Metro is very easy on oil, and mine also still looks amber after 10K. However, on my toyota, after 4K it is getting dark. For diesel or hybrid it is different story, most of diesel produces soot that makes the engine oil getting dark almost instantly. On hybrid, engine is switched off frequently so the engine oil may not get dark fast, but it may suffer fuel dilution fast.

 

[jorton]

Black used oil in good condition looks medium translucent brown on the dipstick, and brown on a white paper towel. Fuel diluted used oil is black on the white paper towel.

 

[mozart]

 Originally Posted By: jorton

Black used oil in good condition looks medium translucent brown on the dipstick, and brown on a white paper towel. Fuel diluted used oil is black on the white paper towel.

Using that definition I quess I have "brown on a white paper" oil. The cars I'm referring to are 2007/8 Toyota/Hondas. From what I've read they do indeed run hot (partially to get emissions down)

 

[mozart]

 Originally Posted By: mozart

 Originally Posted By: jorton

Black used oil in good condition looks medium translucent brown on the dipstick, and brown on a white paper towel. Fuel diluted used oil is black on the white paper towel.

Using that definition I quess I have "brown on a white paper" oil. The cars I'm referring to are 2007/8 Toyota/Hondas. From what I've read they do indeed run hot (partially to get emissions down)

Thanks everyone for the awesome response!

 

[wannafbody]

M1 always turns dark brown for me.

 

[oilyriser]

There are two colour changes. One turns the oil brown starting with a golden hue and getting darker, and the other turns it black like soot. They happen independently, it seems. A good ring seal should keep the soot out.

 

[DeeAgeaux]

 Originally Posted By: ekpolk

 Originally Posted By: DeeAgeaux

 Originally Posted By: ekpolk

The last fill, PP 0w-20 darkened to a mid-brown within a thousand miles. .

Where do you buy PP 0w-20 ?

I've never seen it on a retail shelf. I ordered four cases of it (six qts per case) from Oilstore or Oilshop -- I forget the exact name. Google those and you'll find it pretty quick. Shipped right to my doorstep for a total cost of about what you'd pay at WM.

Thanks

 

[FastSUV]

M1 HM on my 180k mile Jeep 5.9 looks dark-medium brown after 3k for sure... On my 80k mile 4.0L Jeep Pennzoil HM is medium brown on the stick after 4k... I usually try to find the threshhold for top-off and change it...The 5.9 uses M1 after 3k and it is not a daily driver so I change once a year now which is maybe 3k. The 4.0 I had been doing at 4k cause other oils burn off a tad after 4k but the Pennzoil has not burned off a drop so I may try 5k and see what happens.

 

[Geonerd]

A new car is probably producing a fair amount of blow-by, allowing soot into the oil. As the rings settle in, this effect may subside. (FWLIW, my old Accord's M1 oil stays a transparent dark amber for the duration of the oil run, 8000+ miles at last count. I've got 1,700 miles on the latest OC, and the oil is just now starting to take on some proper color. It looks like warm honey on the dipstick.)

 

[Nederlander75]

Sun tan from the furnace in your combustion chamber.

 

[BuickGN]

I think it depends on the oil more than the car. My ACD gets darker in a couple days but maintains the same color through the OCI. The cheap Superflo dino in the GN actually looked nice throughout the OCI but that was only 1,000 miles. The only time I had a problem with it getting black quickly was when I had tremendous blowby from washing the cylinders down with the wrong PROM. Oil temps would hit 300 degrees in normal easy driving.

 

[Gary Allan]

Additives will change color in use. This contributes some color change. Currently, all my oils appear to remain translucent. HDD is only been in a few thousand ..and Bruce's juice has never reached a true dark state over 5k miles.

 

[hpichris]

 Originally Posted By: Warstud

Combustion!

Best answer.

 

[chet2]

buy a domestic, they dont get black as quick...actually i have never owned a car where oil gets black maybe cuz i change every 6k or so...7500 for synthetic

 

[ericthepig]

In my Sienna, M1 would stay amber till 5-6k. Schaeffer would be much darker at 2k.

 

[demarpaint]

 Originally Posted By: hate2work

 Originally Posted By: demarpaint

After changing oil on cars for over 35 years now, I've never seen "black" oil. I've seen some dark colored dirty oil though. I never worked on a diesel engine, so I can't comment about them.

Then you must not remember the old Arco Graphite oil. That stuff was practically black when you poured it in

Honestly I never used the stuff. I am noticing that PP 5W30 is turning darker than any of the Mobil 1 oils did including Mobil 1 10W30 EP in half the miles. My thinking is an occasional change in chemistry might do more cleaning than using the same oil all the time. I always ran Mobil 1 in that rig.

 

[Pablo]

The 20K OCI's I've done, the oil was pretty dark and would almost look black at first glance, but on a bright white towel, very deep dark amber brown is a better description. Even the Volvo last time (with a lot of fuel) was this same color - BUT that fuel was transitory condition, not over the entire OCI. One of the stranger colors was RD-20 in the Honda Ody. It got a little dark at the end of the (~10K) OCI, and had a deep rich mahogany color - which must be from the additive package. I do notice (and have been poo-pooed) - when a customer changes over to Amsoil, the first few OCI's the oil will darken pretty quickly in the OCI. My assumption has been that is clean-up, because after a year or two of this (2-4 OCI's) the same oil stays more translucent and lighter in color for longer than initially. It's all been touched on in this thread. Blow-by, combustion, oxidation, additives (including oil dye itself), VII breakdown, clean up of the previous oil, etc, all contribute to the visual appearance of used oil.

 

[demarpaint]

I'm currently using Amsoil ASM 0W20. I just changed over to it yesterday, and noticed it very hard to see on the dip stick, extremely clean looking oil on the stick. Most other oils I've used were a little easier to see on the stick. Just an observation and comment, nothing more.

 

[jesbo]

I think it depends a lot on the engine. Oil that turns very dark / black quickly may be due to the engine producing soot as a byproduct of combustion. Diesels are big soot producers, so you'll probably see this more frequently in diesel engines. But gas engines do it too. My new BMW 535i with N54 twin turbo, direct inject engine seems to produce more soot. My last oil change came out quite dark after 6K miles. My 2008 Volvo XC/70 (NA engine with port injection) ran 5K miles and the oil was only a slightly darkened amber color. One important role of the engine oil is to keep this particulate matter suspended and rid the engine of it during the next oil change. If this matter sediments out of suspension, you have sludge and deposit buildup... So dark colored oil simply means its doing its job properly. More frequent oil changes may be in order though.

 

[ekpolk]

 Originally Posted By: jorton

Black used oil in good condition looks medium translucent brown on the dipstick, and brown on a white paper towel. Fuel diluted used oil is black on the white paper towel.

Over the years, I've heard various descriptions of this phenomenon that match or are pretty close to this. I still wish I'd known more back in the 80s when I had that Jetta. It's oil got so hideously black, it looked like a diesel -- almost. I got rid of that car pretty quickly, but for other reasons (it was badly crash damaged, and the repair was awful). It would be very interesting to see a UOA on that car.