I rarely post but just figured i'd say, that my 2001 4x4 f150 with the 4.2 147,000 miles has been smoking after start up lately with 6 qts of oil addded. I never had the owners manual since day one. I always added 5qts of oil and it was perfect - then i realized i was always a quart low. well when i added the extra qt it would only smoke at start up. I was prepared for the cool v8 swap or a new set of heads or a rebuild... I used carquest brands engine flush and now it runs perfect, NO SMOKING and i'm back to using 6qts of oil as required. I doubt that 5qts ever affected anything because i changed the oil at 3,000 miles ALWAYS. must have been the varieties of cheap oils that sludged up my rings etc... or just coincidence that it started to smoke a little at start up around the same time i read it takes 6qts.. but either way my trucks been fine since i used the engine oil flush.

 

Now make sure you use the recommended oil - which is 5W20 that meets Ford 930 specs, and a quality filter. You cannot go wrong with Motorcraft oil and filters, both of which are available at Walmart.

 

Im not sure what you did to flush it or what kit you had but i work for NTB and we have "oil system cleaner" and i dont like it. I put it in before i did my oil change and now the front of the pan leaks, i was told it was the chemicals in the cleaner that eats away at the seal. So no more cleaner for me and now i need to replace the front gaskit.

 

smoking at startup is usually due to valve seal leaks, its possible the engine flush had a seal swelling additive. might only be temporary but who cares...

 

What brand did you use?