How long after a diesel OC does the oil turn dark?

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I know dark oil in a diesel doesn't mean it's bad or hasn't been changed in a long time but how soon after an oil and filter change will it turn black? And does the oil in newer clean diesel engines stay clearer longer? Have a 92 Chevy with a 6.5TD that I bought 7 years ago that's been sitting and will do my first oil change on it. Will probably do a second one after a few miles to get everything cleaned out.
 
Have a 09 6.4l Powerstroke in a work truck and it stays clean looking for about 5 minutes after you change it...lol

Not quite that extreme but after it runs you start to see some darkening in the new oil and after a few days you cant tell it has been changed recently.

AFAIK even new diesels darken their oil quickly, unless something has changed in the past few years.
 
It depends on the diesel engine-for instance, the 6.2 GMC in my sig will actually stay reasonably clear for 1000-1500 miles, but the Cummins in the Ram, with it's in-cylinder EGR and 3rd injection event, gets pretty black in the first couple miles. My old '02 Ram Cummins with VP44 IP and no EGR would also take 1000 miles or so to turn black.
 
When I disabled all the emissions equipment in my 2004 Volvo Semi, the oil would stay clean for THOUSANDS of miles.

With EGR working, the oil was black right after an oil change during the oil level check.
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Same for the old Mercedes diesels I had. The oil darkened very quickly after a change.
The oil would drain out jet black, darker than anything you'd ever see with a gasser and also had a distinctive scent.
 
With a standard fill flow filter?

Within 5 minutes.

With a bypass filter, or a dual stage strata pour venturi - its stays clear a long time .

UD
 
Don't expect it to be clean for more than just a couple minutes, any time soon. I can't speak for the newer, cleaner, common-rail diesels, but every mech. injection oil burner I've changed oil on - even ones that were serviced regularly, at mfg. intervals - it's pretty much black when you check the level after start-up. The only exceptions to that I've seen (with conventional filtration) are engines that were substantially, regularly over-serviced.
 
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Originally Posted By: fdcg27
Same for the old Mercedes diesels I had. The oil darkened very quickly after a change.
The oil would drain out jet black, darker than anything you'd ever see with a gasser and also had a distinctive scent.


That is my experience too. It doesn't take much carbon black to make ink. It doesn't take much oil residue to make the oil go jet black.
 
Originally Posted By: Alex_V
I can't speak for the newer, cleaner, common-rail diesels...
I have a 2015 Ford 6.7L Powerstroke and it takes minutes for the oil to begin to turn black, but it remains dark translucent for about 100-500 miles (depending on regens) and after that it is coal black (and stains like it too).
 
In my Powerstroke I do not change the bypass every time so some old oil is in the bypass filter. Turns black when checking the dipstick after the initial start-up after the oil change.
 
Do a blotter test after you've changed the oil - it won't be as dirty as it looks, the test will come out like clean oil.
 
Can I use Lubriguard 15W40 CJ-4/SM I've had on the shelf for years? Don't expect to start the truck below 20F but the 15W seems thick for an engine that has high compression already working against it in cold start ups.
 
Originally Posted By: atikovi
Can I use Lubriguard 15W40 CJ-4/SM I've had on the shelf for years? Don't expect to start the truck below 20F but the 15W seems thick for an engine that has high compression already working against it in cold start ups.


All through the 80's and 90's that was all we used in North Dakota winters.

Synthetic oil that was less that $10 a quart (!) didn't really exist much.

I hand-crank started a Farmall M with 30W in it when it was -35*F. It lit right off.
 
My old ZD30 Navara got about 2500-3000km of clean oil...then it was black but still see through....didn't get "solid" black until about 6,000km.
 
My first diesel was a 2092 Ford F350, Super Cab 4x4 Power Stroke with the International built 7.3, great truck, great engine. I changed the oil and oil filter every 5000 miles or 6 months, which ever came first. I used several different brands of 15w40 oil, but mostly the MotorCraft oil which was made for Ford by Conoco-Phillips,great oil and always the MotorCraft oil filter. The oil actually stayed fairly clean at 5000 miles or 6 months, being a light brown. I am sure this was due to the absence of the emission control [censored] that the newer diesels have now.

I presently own a 2011 4x4 Ram Laramie Crew Cab with the Cummins. Great truck and great motor. With the emission [censored] on this truck, my oil is black only a few miles later, again because of the over kill of the emission [censored]. I change the oil and oil filter every 5000 miles or 6 months, which ever comes first. I use the Shell Rotella T6, 5w40 synthetic diesel oil with either the Mopar oil filter ( made by Cummins for Mopar) or the Cummins Oil filter.
 
Oil in my 7.3 takes about 1000 miles to change, even then it doesn't ever get coal black and stays a dark translucent on the stick, I can see the crosshatches if I look closely. The emissions garbage on new diesels are to blame for the oil turning black almost instantly. My truck has no emissions equipment and I like it that way! Lol, back before the EPA ruined diesel engines. Doesn't help the cause when these rednecks and punk teens go around blowing black smoke on pedestrians and other motorists, either.
 
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