I have a 2002 7.3 ltr that has aprox. 225.000 miles on the BEAST I love her to death completly stock and will pull any thing I need to but not ever come close to it's capacity rating.My ? is that when the oil is changed every 4-5000 miles why after 100 miles is my oil black. I have allways used Rotellla and a Motorcraft filter. A local deisel shop recomended that I start using Motorcraft oil which I did and in addition a K&N oil filter. Does anyone have any suggestions. BTY I'm new to this Forum and hope I'm not posting in the wrong section and I did some searching before posting. Any Help would be appreciated. Thanks for any help.

 

Oil turning black on a diesel is very normal. Remember that when you see a diesel truck under load, many times you see black smoke, its extra fuel being burned and producing soot particles. The oil in a diesel engine has to serve double duty, not only does it have to protect against wear, it has to be able to do it under a much greater soot load than that of a gasser. It has to be able to protect the engine while encapsulating the soot particles and preventing it from doing damage to internal engine components. A couple of questions...How long have you had the vehicle? Does it smoke heavily when accelerating? any performance issues you've noticed? Any noticeable drop in fuel economy? Alot of soot (more than usual) under load or acceleration and an appreciable drop in fuel economy can be the result of a fuel injector or two bypassing extra fuel. Hence the reason for the length of ownership question.

 

Bought it when it was about 4 years old and knew the PO very well and he kept very good maintainance as well. Very little smoke on accelleration and for the most part the heaviest thing it pulls on occassion is a jeep on a 20' carhauler which is hardly even noticed. Also no decrease in fuel mileage,except when I put slightly larger tires on it. It just seems that my oil would not get black within 100 or so miles after a change.Thanks for your input.

 

When I ran motorcraft 15-40 I lost about 3qts every 5,000 miles. I switched to RotellaT and lost only about a qt every 5,000 miles. That k&n filter should be be put in the closest trash can ASAP. That's my opinion tho, ford made the filters for our trucks and that's The only brand I ever use on any of my fords. Also they are 9.00 at Wallyworld and they usually have the cheapest oil prices. Also my motor seemed to run quieter on rotella. I would say next oil change go back to what works. Remember most all semi trucks run rotella, devlac, or chevron dello. If the big boys run it I think it's stood the test of use and time.

 

Part of the issue is there are about 2 quarts of oil left in the motor when you do the change, but as stated, this is nothing to be concerned about on the 7.3. I've used Rotella and the motorcraft filter for plenty of miles with no issues.

If you want it to look cleaner after 100 miles, next time you change the oil, leave the drain plug and oil filter off for at least 30 min. to drain out as much as possible. You could even change it again after 1000 miles or so to help flush the older oil out. I wouldn't expect your truck to run any better or last any longer by doing this, but if it makes you feel better, then perhaps it's worth it.