Have a Lincoln Navigator, 2004 with 99,000 miles. Just off extended warranty, no issues.
Basically have been getting 5k changes with Motorcraft 5-20, twice at Valvoline Instant with their syn blend.
The Motorcraft is a blend, and inexpensive, but the dealer doesn't get oil changes out in less than 2 hours. The valvoline blend is convenient, but with 7 quarts, gets expensive.
Would conventional 5-20 from Valvoline, or Pennzoil be ok?
Did my own changes in the 80's, but don't want to get into ramps to get under this beast.
Robert