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T6 15w-40 not cleaning engine?

4K views 23 replies 11 participants last post by  barongan 
#1 ·
Just got a question for those of you that have been running the new T6 15w...I have a 1000 miles on this oil since last oil change and it still looks like new. All my previous oil changes with T6 5w turned black almost immediately it seemed which would indicate that it was cleaning. Anyone done a change with the new 15w and monitored it lately?
 
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#3 ·
you're over thinking it... When I first switched to the t5 5w-40 and now the t6 15w-40 the oil looked new for the whole change interval, The synthetic seems to really stand up well in these trucks. The oil turning black does not in anyway shape or form indicate its "cleaning the engine" its merely build up of soot and other matter from the engines process of running.

Your oil and truck is totally fine.
 
#4 ·
So, i've owned this truck for 18 months, did an oil change immediately when I picked it up and 2 since. First 2 with T6 5w and third with 15w. One change I added Seafoam to the crankcase. I'm going to think of this good looking oil as a positive then.
 
#6 ·
This is exactly what I've heard from others as well. If it's black, it's doing it's job. The result of cleaning diesel soot. Question is, why do some experience black oil every time and some don't? Mods maybe, larger injectors, smokier truck...?
 
#7 ·
I have no idea why some are not claiming to have the same black oil as the masses
my truck has always had black oil
no crazy mods ccv delete egr off bypass filtration and OEM filtration

soot is such a fine micron that most say the black oil is a non issue
FS 2500 said it is ok when i asked them why my oil was not golden like their ad
 
#8 ·
I can send a picture of my oil if it helps anyone. I have the fumoto valve and extra oil. But since swapping to full synthetic I have not had black oil. Could be because I don’t have an egr, def/dpf?

1999 F250 7.3L. With 152k miles running t6 15w-40. Little over 2000 miles and oil looks like it did when it came out of the bottle.

Stock injectors, no ecm tune, ccv re route for about 500 miles. Straight pipe etc. no fuel, injector, or tuning etc.

I had the same results using the t6 5w-40 at 4500 miles it was same color as out of the bottle.
 
#10 ·
The oil has always turned black in mine after a few miles of driving, same goes for any other diesel I have changed the oil in. Black oil is normal for a diesel, even the pre emissions ones.
 
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#11 ·
The oil has always turned black in mine after a few miles of driving, same goes for any other diesel I have changed the oil in. Black oil is normal for a diesel, even the pre emissions ones.

When I was using conventional oil it turned black within days that was on almost every diesel I drove from equipment, little Volkswagen cars, powerstrokes and cummins (never drove duramaxs) BUT, since I started using the full synthetic the rotella t6 5w-40 and t6 15w-40 has stayed golden honey colored throughout the oil changes. I usually do it 5k if not a tad before since the truck either sits for a week or tows when I do drive it. I was very used to the oil turning black instantly but I feel oil technology has changed so much there has to be something different. I wont ever say bad as my trucks runs great on the synthetic stuff but my oil hasn't turned black in the 1999 7.3 since using it.
 
#12 ·
The oil turns black because the detergents in it capture the soot that the engine produces. If you oil is staying clean then it isn't picking up as much soot as the oil you were using before.
 
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#16 · (Edited)
That's true, your oil turning black with soot is not a problem. This video explains it pretty well.
 
#17 ·
I’m at over 3,500 miles on my current T6 5w-40 and it still looks gold on the dipstick, just a tint of black. It would look black if I drained it though

My dads is the same way on his 98 e350. He’s approaching 300k on original injectors and runs mixtures of waste oil

Neither of us change our HPOP oil regularly

Different engines behave differently. In my 99 TDI and my moms 06 TDI the oil will turn jet black on the stick instantly


Sent from my iPhone using Tapatalk
 
#18 ·
#23 ·
My 97 7.3 will turn dark before the 5k mark. When I bought it I was using the t3 15w40 like it had always had and I (tried to) changed it every 3k. I'd say for the last 30k+ it's had t6 5w40 every 5k. It loves it, especially in the cold weather up here, I've never had an starting issue with it here (with a good relay of course). Last year when we were -30 she started and ran until she starved for fuel as it was gelled. I wouldn't have tried it but it my 6.7 was having issues too. My 2015 6.7 started with 10w30 (I'd assume motorcraft since it was a Ford thing) but I'm not a big fan of 10w30 as a diesel oil. I've ran t6 5w40 the last 30k+ (still 5k changes) and it is dark instantly and it is black as black when changed (still has all EPA BS since it's under warranty).
I also will top off the oil 100 miles or so before an oil change with transmission fluid as it is a great detergent and will break up any stuck carbon, that'll darken it a bit in the 7.3 at change and the 6.7 is still black as black. I personally love the t6 5w40 and have't ran anything different and probably won't.

Just my $.02 worth, for the same $$$ I'd switch to the 5w stuff since it also gets moving faster when cold (lube sooner is better) and I know it cleans mine.
 
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