Cause of oil darkening?
- Thread starter Tommy
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I wonder the same thing sometimes. I change my gf's oil at 3k miles(give or take 100 miles) and it comes out dark. I take decent care of the car. I clean the maf every change, the air filter is good...... Its got about 1500 to 1750 on it now and its starting to turn. I am runnin good ol dino Mobil Drive Clean. She does have an all aluminum Mitsu motor.
I have a Focus, I have been using the MC 5w20. My oil does darken a little by 3k, but not BLACK like hers....the sad part is that I am running a K&N air filter.
Eric
I have a Focus, I have been using the MC 5w20. My oil does darken a little by 3k, but not BLACK like hers....the sad part is that I am running a K&N air filter.
Eric
1. Contaminents are being suspended in the oil instead of deposited on internal engine parts.
2. Some oil additives darken because of a chemical reaction caused by heat.
Gene
2. Some oil additives darken because of a chemical reaction caused by heat.
Gene
O.K., sure, contaminants will of course darken oil. What I am talking about is oil that has been run in a new engine for only a few thousand kilometres - hardly enough time to load up the oil with contaminants in a clean engine.
Additives turning colour with heat is exactly what I have read - if heat causes these additives to darken, why does it take so many heat cycles for the darkening to begin?
Is it possible that the colouration is really coming from the aluminum in the engine parts?
Additives turning colour with heat is exactly what I have read - if heat causes these additives to darken, why does it take so many heat cycles for the darkening to begin?
Is it possible that the colouration is really coming from the aluminum in the engine parts?
I was thinking that, but in 3k the oil level doesnt drop off (Im guessing its not burnin at all). Also she used to get it serviced wherever and whenever because she didnt want to bother me with it. I think I am doing a good job with it now and its gonna clean up nice. Is there any test for blow-by other than compression test?
Eric
In my opinion, this has more to do with the specific motor/application than the oil. Case in point, I can put oil in my wife's '95 Civic, and it will still be a pretty amber on the dipstick when I'm ready to change it out 3000 miles later. Put the same oil in my '99 Saturn, and it's black as coal within 1000 miles. Doesn't matter what brand of oil, doesn't matter what kind - synthetic or otherwise, and it's been that way since both were driven off the respective lots. Different engines run at different levels of cleanliness, and thus treat the oil differently. Same reason different engines have different "trends" shown on UOAs.
Originally posted by Dr. T:
[QB] And the funny thing is when the oil gurus say that the color doesn't matter.
I used to run Castrol GTX and it would get dark driving around the block. Old Equilon Havoline tended to stay golden in the same engine.
Since neither got consumed, I don't think it indicated blowby or anything unusual.
Kev, I noticed the same thing in all my Saturns, until this past month. Using LC/FP, M1 didn't get dark until the 2800-2900 mile mark. I was quite amazed how "un-dark" the oil was at the 2000 mile mark on that OCI. I took a sample, but haven't sent it in yet.
My Ams 0W30 got fairly dark around 2000 miles(Nissan Maxima), but the UOA at 6000 showed it still had a lot of life in it (TBN 8.75). Now my wife's Mitsu Eclipse (4-banger) turns any oil dark at around 1300 miles. And this is after a good ARX clean and rinse. Currently running Ams 0w30 in the 4-banger since it did well in the Max.
Pedro
Pedro
Don't know about that, but I tell you what I do know.....the "new" Pennz. 5W-30 is a heck of a lot lighter in color than before. Changed the oil this weekend and freaked me out. I had read on here that that is whats happening, but didn't expect it to be that much lighter. Wow. It was such a difference that I thought I had bought the wrong stuff.
Bump.
Good morning everyone.
I always believed that it was a mechanical problem that caused my the oil to turn jet black 100 miles after the oil change (91 oil burning civic). But this article helped me understand it in more detail:
"...the piston rings slowly wear into the surface of the cylinder wall, creating tiny imperfections. These gouges or scratches then create a channel for pressurized combustion gasses to slip past the rings down into the crankcase. ...this "blowby" contaminates the engine's lubricating oil with combustion gases containing acidic compounds."
I've always been aware that oil was passing through my rings and out my exaust. (Geez, anyone within 30 yards is aware of it.) But I didn't know that unburnt fuel was seeping out of the combustion chamber and mixing with my oil, turning it black.
Ableit, i'm sure many of you already understood this.
Good morning everyone.
I always believed that it was a mechanical problem that caused my the oil to turn jet black 100 miles after the oil change (91 oil burning civic). But this article helped me understand it in more detail:
"...the piston rings slowly wear into the surface of the cylinder wall, creating tiny imperfections. These gouges or scratches then create a channel for pressurized combustion gasses to slip past the rings down into the crankcase. ...this "blowby" contaminates the engine's lubricating oil with combustion gases containing acidic compounds."
I've always been aware that oil was passing through my rings and out my exaust. (Geez, anyone within 30 yards is aware of it.) But I didn't know that unburnt fuel was seeping out of the combustion chamber and mixing with my oil, turning it black.
Ableit, i'm sure many of you already understood this.
Skate,
If over time more and more "pressurized combustion gasses to slip past the rings" would that mean increasing rate of oil polution, hence shorter OCIs? In other words, as a car ages should its OCI be adjusted down?
If over time more and more "pressurized combustion gasses to slip past the rings" would that mean increasing rate of oil polution, hence shorter OCIs? In other words, as a car ages should its OCI be adjusted down?
Quote:
And the funny thing is when the oil gurus say that the color doesn't matter.
You just hit the nail on the head. You demonstrated that you're changing the oil too early on the civic, and the saturn needs oil with more cojones.
A Saturn definitely needs an oil with conjones, to keep those rings clean. Or else they burn like an oil furnace. I'm using GC in mine, and notice a nice improvement.
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