Black engine oil!?

[MikeOneZeroZeroNiner]

I bought my M1009 about a month ago, with 10,690 original miles. This is my first diesel, and I want to become extremely familliar with it, as it is going to be my BOV eventually.

I checked my oil last night for the first time at a gas station with really poor lighting. I could see well enough that with the engine hot it read "FULL", and the color was dark, so I knew it was time for an oil change (I don't know when the last one was performed)

Today, I'm laying on the ground, I take off the oil filter and some oil ran down my arm, and I moved out to the light to look at it and the oil is PITCH BLACK. I mean BLACK AS SIN. I've never seen anything like this before. Is this something I should look into with a mechanic? I used a flashlight to see what color the oil coming out of the drain hole was, and it's (obviously) black as well. I'm kinda nervous about this as I JUST bought the truck, and I'm having problems already.

Any ideas what could be going on or is this fairly normal?

Unrelated: Oh yea, and on the freeway last night, I blew my rear passenger tire. Scariest moment of my life.

 

[camogriz]

Not sure if it helps, but i frequently find that the oil in my CUCV's turns pitch black soon after it is changed. Motor oil generally turns black as a result of extreme heat, and I guess there would be a lot of heat in a motor that has a 21 or 22 to 1 compression ratio. There also may be some soot from the combustion process getting into the oil past the piston rings in a 25 year old truck. If the oil does not have any grit in it, the truck may be OK. Just change the oil and moniter it from this point. Your condition may be normal.

 

[emmado22]

How do you kow it is 10k original miles????

 

[ClintA]

No worries mate, welcome to the diesel world. Your new oil will be BLACK as night in no time, but it will still be good. Diesel's, gota love them.

 

[hilber]

Engine oil turns black in Diesel's pretty quick, or it does in any I have ever seen or owned. Unless its using oil, or something unusual is in your used oil, I wouldn't worry about it.

 

[natem]

Black oil is normal in diesel motors. Even new ones.

 

[mudman]

Black oil is the norm. Even after aday or two...By the way it stains too.!!

 

[supermechanic]

I would worry if the oil didn't turn black.
That would mean that the soot is collecting inside the engine.
Modern detergent motor oils are designed to hold the soot/dirt/anything else in suspension, that way the soot/dirt/& ect. leaves with the oil when you drain it.
Design feature, worry if it isn't dirty.

 

[M813A1]

Yes it is normal for engine oil in a diesel to turn black !! As Super mechanic said thatis the reason that the oil turns color along with the compounds that are used to make diesel it creates the black oil all the sooting and sulfur build up help the oilto turn colors

 

[DriverSideImpact1008]

Normal for any diesel. I can't say I've seen many, if any, diesels that didn't have black oil. Everything from early 80's 5cyl Mercedes, 6.0L Powerstrokes, up to Cummins ISX's.

Just do as you would with any other vehicle's oil. Check the level, color, the texture, smell, etc... if it's not normal, then look into it.

 

[TheWeatherMan]

Welcome to the crazy world of diesel... soon you will only be buying diesel vehicles. But yes black oil is the norm in these trucks. You know how diesels put out black smoke? Well that makes your oil get dirtier a lot faster than a gas engine. No you dont need to change it more often. Just calm down now and enjoy the chatter of that diesel.

 

[MikeOneZeroZeroNiner]

Wow, that is a MAJOR relief. For some reason I have a knack for buying cars that are held together with invisible duct tape, it's good to know that this isn't the case for this CUCV.

Thank you everyone for your reassuring info!

 

[BLK HMMWV]

Your post brought a smile to my face. I had the same exact reaction when i bought my HMMWV. The guy I bought it from told me he had just changed the oil and filter. I checked the dip stick and said a few choice words. Changed the oil and filter again. Have fun with it . He also told me that they all leak fluids, it's only a problem when it stops leaking that means it's out of fluids.

BH

 

[nf6x]

Now that you have been anointed with the sacred black diesel oil, you are one of us! We don't have a secret handshake or anything... we just stink of diesel fuel.

 

[Loco_Hosa]

Its possible that it has not been changed for a while, and its never a bad plan with a new purchase to do an oil change after buying, then another 500 miles later. Walmart sells Rotella 15w-40 (This is a very decent oil, designed for a diesel) cheap enough to make this feasible.

However, I wouldnt worry too much. Just makes it easier to check the level! I used to like Royal Purple in my hot rod because it was a darker color and showed up better on the dip stick!

 

[idM1028]

Yep. Black oil is pretty much the norm for a diesel. My understanding is that the oil catches all the soot and crap from the fuel turning it black. Same reason why you'll get black smoke from a diesel (unburnt diesel fuel in exhaust) Another good check while you're messing around with your oil is to take the filler cap off with the engine running. Do you see smoke or fumes coming out? If no, then good. This means your rings are sealing and doing their job and you're not getting blow by. Another trick that I try and do is drop a bottle of Diesel Kleen in my tank a couple hundred miles before my next oil change. Supposedly, this stuff will knock all the crap loose and keeps in the oil, so you get rid of it when you do your oil change.

 

[tgtaylor64]

Does anyone follow the recommendation for engine oil weight listed on the back of the sun visors? It says SAE 30 above 40°F and 10W-30 below 40°F, with either recommended between 40-60°F. I have always run Rotella 15W-40 because everyone else does. I am thinking about changing to the SAE 30 in about a month or so in South Carolina for the long summer. Any comments about better performance or mileage?

 

[emr]

Wow, that is a MAJOR relief. For some reason I have a knack for buying cars that are held together with invisible duct tape, it's good to know that this isn't the case for this CUCV.

Thank you everyone for your reassuring info!

Well, Your truck has a lot of quirks U will soon find out about, It is an antique and it has a motor that should not be beat on, but its a fine truck , that needs alot of cuddling

 

[wayne pick]

Mike Zero Niner, Welcome to the mad, mad world of MVs. Keep in mind these are OLD trucks no matter how low the milage may be, or what condition it's in. Your odometer may be correct. If it is, that means it sat more than it was used-26yrs. Uppon receving your truck, u should go over it and check all the fluids, brakes, TIRES. Read the TMs, this will familliarise you with these trucks. Next oil change, get your self some Sea Foam at your parts store. One can in the engine oil, one day prior to changing the oil and one can per 20gal in the fuel tank, it blows carbon and sludge deposits out of the engine. Do the doghead starter relay upgrade and get some new tires on that thing. Old dry rotted tires tend to blow unexpectidly. Once you shake the bugs out of your truck u will really injoy it. Good luck! WCP

 

[donalloy1]

Outstanding Post! Wealth of information for all.

With lubricant quality the way it is today. Gather we can get more miles out of Motor Oil. Otherwise we are just dumping oil that is still fine. That being said. Is changing crankcase oil at 5k miles and beyond acceptable on CUCV Diesels?