Okay so here's my situation.......

Bought my current 5.4 in an '00 E250 with 203K miles, all original and since its first oil change I've used mostly NAPA or Valvoline high mileage 10w-40 every 3K miles along with Lucas conditioner. At first there was a slight but noticable slap when first starting which I was told might be one of the lower rod bearings. With 250K miles now that slap isn't noticable but I'm sure it's not cured either.

Am I doing any long term damage or other disservice to my engine? I'll either trade/sell this van once I've located another suitable one but may also consider a new Ford engine in the meantime.

Any advice or first-hand experience with the higher viscosity oils would be greatly appreciated.


Thanks