Oil Color

   / Oil Color #1  

Gomez

Gold Member
Joined
Apr 7, 2000
Messages
429
Location
Bucks County, PA
Tractor
Kubota B2400
I just changed the oil and filter in my B2400 over the weekend. The oil seems to get black very fast. I put about an hour on the unit since I changed the oil, and now the oil is about as dark as the old oil was. Is this the way it is with diesels?
 
   / Oil Color #2  
Gomez, unlike gasoline engines, I've never seen a diesel engine in which the oil didn't turn black awfully soon after a change. Sounds normal to me.

Bird
 
   / Oil Color #3  
The oil in my new Kubota was so clear it was nearly impossible to check on the dipstick. After 25 hours of operation it is possible to just see a little color in the oil. After how many hours does the very dark color start and where does it come from?
 
   / Oil Color #4  
Couldn't agree with you more. I found the same thing with my 1700, and I GUESS the oil works just fine even when it looks dirty, but now that i went synthetic I don't have to think about it anymore - mine looks like it came out of the bottle after 15 hours so far.
 
   / Oil Color #5  
On a brand spanking new engine, it does take awhile before the oil turns dark, but on all the changes thereafter, it'll turn dark very quickly. Or at least that's been my experience with diesels, and that of other people I've talked to. Now, PaulB says that synthetic oil stays looking cleaner longer. Can someone give me a scientific reason for that? Or even a wild guess?

Bird
 
   / Oil Color #6  
Nope. But I swear on a stack of bibles it is true, based on my observations at 15 hours of use so far. If it changes as the hours add up, I will post on it.
 
   / Oil Color #7  
PaulB, I predict it will change to get about as dark as the petroleum did. In most, but not all, engines, synthetic doesn't seem to get dark as quickly as petroleum does, but I don't know why this is, or even if it's a confirmed fact.

I do know that the black stuff doesn't hurt, and there are many who say it has a 'plating' effect that prolongs the life of the engine. I also know that a .5 micron filter will not take it back out, and a centrifuge-type filter won't remove enough of it to change the color of the oil, so the stuff is very small and light.
 
   / Oil Color #8  
An important function of engine oil is to keep the particles that are too small for the filter to remove in suspension in the oil. This stuff will then be removed at the next oil change.
If synthetic oil does not get as dark as regular oil under the same conditions, then it must not be doing it's job holding these particles. This would allow the crud to build up in the crankcase where, in the future, a large amount of it could be released all at once causing a problem.
All modern oils that I know of are very good at holding particles in suspension. The clean oil in the post above, is most likely due to how new the tractor is.
This just goes to show how testimonials about how good or bad a product is can easily be influenced by unrelated factors. Most if not all the things said here about synthetic oil, with the exception of it's cost, fall into this catagory. Claims about a product are only meaningfull if there is a large enough sample tested under controled conditions.
My personal favorite (sorry Mark) is the claim that synthetic oil significantly increases the life of head gaskets in Volkswagon Rabbits. This was "proven" by comparing several synthetic lubricated Rabbits to several Rabbits using conventional oil. If I remember correctly the synthetic Rabbits head gaskets significantly outlasted the others... conclusion it must be the synthetic oil. Much more likely is that the owners of the Rabbits willing to pay the extra cost of synthetic oil took better care of their cars and torqued the head bolts or performed other maintainence more often, resulting in increased life. Without a controlled test we will never know the real reason.

Andy
 
   / Oil Color #9  
It's impossible, as you say, to prove or disprove such claims, but, unfortunately, your claim falls into the same category. I can tell you of my experience. In all the VW diesels my father and I have owned (except my current '96), none of them have less than 250k miles and several more than 300k, one over 400k, none of them ever retired due to engine failure, none of them ever even had any engine maintenance other than routine timing belt replacement, none of them have ever had the heads retorqued, not even once, none of them ever had the valves adjusted (though the early models 'required' it as routine maintenance), none of them even had the oil changed more often than once a year. I don't think this would qualify as 'better care' or more frequent maintenance in anyone's book.

I don't think the synthetic has anything to do with the head gasket directly, personally. It's the increased heat handling capability that does it, I think. At any rate, it clearly is the oil and not the maintenance.

The fact of the matter is, in my opinion, that most people who refuse to look at the fairly obvious evidence of synthetic's superiority in the form of their specs, will also dismiss the controlled tests you speak of, as well. I don't know why, it's just the way it is. I hope never to be so closed-minded myself. (My prejudice against GM products excluded, of course.)
 
   / Oil Color #10  
Black oil is the nature of the beast in a diesel nothing to be alarmed about. I have always used regular oil in my diesels changed at normal intervals and have logged many hours without an oil related problem---One of my current kubotas has over 7000 hours on the engine with a very small amount of blow by but runs like a champ.
 
   / Oil Color #11  
It is entirely possible that you would have had the same service life from those cars with conventional oil in them. there is no way to tell if this would be true or not.
My personal opinion is that synthetic may indeed be superior, however, my personal experience with synthetic was that it broke down and did not lubricate properly after only a few hours under less than extreme conditions ( the engine started knocking and the knocking went away as soon as I changed the oil). Since it was not a controlled test and on only one vehicle, it does not really mean anything.
Most estimates of compact tractor engine life using regular oil are 5,000 hrs give or take. It will be a rare person on this forem using synthetic that will ever even appoach those hours. Most will sell, trade or die first.
The point I was trying to get across is that first person testimonials, while they may be emotional and change opinions and work great to sell a product, rarely are important from an engineering perspective.

Andy
 
   / Oil Color #12  
Understood. And agreed to, even.

And the point I was trying to make is that the same people who believe that first person testimonials mean absolutely nothing will also excuse controlled tests as 'rigged', or distorted by emphasizing certain data while ignoring other data. All of which goes to prove, if I may use the word, that it's impossible to prove anything to these people. A similar mentality exists in those who still believe man never went to the moon. If you could physically take them there, they'd swear you somehow slipped them a halucinogenic drug and faked the whole thing.

Reminds me of the light bulb joke: How many psychiatrists does it take to change a light bulb? Only one of course (psychiatrists are very clever folks), but the light bulb does have to want to change.
 
   / Oil Color #13  
I must say I was skeptical about synthetics, but after reading Marks comments, I switched last
fall to synthetics in my car (90 Caprice--GM--sorry Mark but I do like my GM cars). Its been
8,000 miles since I changed the oil with the synthetic oil--Amsoil, I can tell you it looks like
I just changed it. The Car had 184,000 miles on it when I switched, and the oil would get darker and thicker using the old oil (Quaker State Super Blend 10W30) and I changed it religiously every 3,000 miles. I guess I'm getting lazy in my old age and didn't want to crawl under the car any more than I had to--so thats why I switched---judging from the looks of the oil, it should do quite nicely for a once a year change-(of course I will change the Amsoil filter at 12,000) per recommendation by Amsoil. The crazy part is I will actually save money--even with the added expense of the synthetics. I bought a B2710 last fall--only 7.0 hours on it, but I will be using
synthetics in that, when I do my 50hour maintenance, but in the engine and HST system. Too soon to tell if I made the correct choice, but you can't argue with the testing or the results that show Amsoil is superior to nonsynthetic oil. I can't speak for the other Companies out there that make synthetics, because I haven't seen their data as done by independent labs. I have a lot of respect for Mark's opinion (except when it comes to GM), and Bird too even though every
farmer I've talked to in my area Springport Michigan--says rotella is years behind in the current
oil performance category---no--I'm not slamming anyone just telling you what they've told me,
most farmers in this area opt for the John Deere brand Heavy duty diesel oil--of course who knows who makes that for Deere. I plan on keeping my Kubota for 25 years--by then I'll know if I made the right decision. In the meantime I'll keep you posted if any problem develops.
I really do enjoy reading on this forum, and have learned more than I'd care to admit.

Thanks-- Mark, Bird, Paul, and others who have contributed their knowledge and expertise
 
   / Oil Color #14  
RodT, no need to apologize for your preference for GM products. My prejudice doesn't extend to owners of GM products, just as far as the products themselves. (Some of my best friends drive GM products - and I don't drive around with a "Friends don't let friends drive Chevy's" bumper sticker. As I've said numerous times, it's primarily because of their light- & medium-duty diesel record. I happen to know they build some excellent heavy-duty diesels, but that doesn't even the scale when you're prejudiced. Besides, it makes it a lot easier to pick favorite NASCAR drivers when you've got a definite auto make preference.)

The darkening of petroleum faster than synthetic which you refer to in your message, is entirely different from the darkening in diesels that PaulB was talking about, but I'm sure you knew that. The darkening you're talking about with petroleum is just plain aging - evaporation, deterioration due to temperature extremes, etc., things which synthetic is relatively immune to, and which allow it to be used so effectively in extended-drain applications. But please, don't start telling people they'll save money using synthetics, they'll make up some other excuse that's a lot harder to argue with - such as not liking the smell of it or something. (Just between you and me, I've always made up at least the difference in increased mileage, and in many vehicles it's been enough of an improvement that it would completely pay for the oil and filter, not even counting the reduced quantities needed by extending drain intervals.) And nobody will ever sucessfully argue the point that increased mileage doesn't translate to reduced wear, which has to be worth something, if only to the person who inherits it when you bite the green weenie.

Thanks for your input and experience - it's what makes this forum so informative.
 
   / Oil Color #15  
A few comments about oil. The darkening of oil is due mostly to suspended carbon particles, but also due to sludge from the breakdown of the oil. Diesel motor oil gets darker quicker because they produce more carbon than gasoline-fired engines. Diesel engines also run hotter, which leads to faster oil breakdown and more sludge. The reason synthetics tends to stay lighter longer is that they do not break down as readily or sludge up as fast. All of the carbon chains in synthetic oil are the same length, whereas the lengths vary in conventional oil derived from crude oil. The lighter, shorter-chained hydrocarbons tend to evaporate in conventironal oil, leaving sludge.
 
   / Oil Color #16  
I've had good luck with regular oil not to say amsoil is better or worse I have nothing to compare it to. Say if now I switched to amsoil on a tractor with alot of hours on the meter would help or hurt its life-span-----open for suggestions----If I could get a couple thousand more hours by running amsoil before a teardown it might be worth looking into for me. How much does it run a gallon compared to regular oil? Thanks Gordon
 
   / Oil Color #18  
Gordon - you can get it fpr $19.10 a gallon from their website.
Everybody - remember my post on the old forum about air bubbles in my amsoil? I just had a thought - maybe all oils have bubbles in it, and I can just see it in mine because it is so clear?
 
   / Oil Color #19  
Remember it?!!? How in the world could we forget??? /w3tcompact/icons/wink.gif

Interesting possibility - I guess we'll all just have to start examining our dipsticks more closely...
 
   / Oil Color #20  
Thanks for the info Paul. Just to pick a number out of the sky for alot 5000 hrs. Would that be to late in life for a change of oil type's? Or is it never to late? Am open for suggestions always willing to learn---Thats one of the main reasons I'm here. Thanks Gordon
 

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