My sons new style 2004 F-150 Lariat with the 5.4 3 valve engine, 60K miles, still seems to be a bit dirty inside the engine. He has been letting the Ford dealership he works at, change his oil every 3-5K miles. When he was changing it this past weekend l noticed it was very dirty for 5K miles. Before he bought the truck it had sat in a garage for almost 8 years. He bought it with 4.8K miles on it and the oil had not been changed in almost 9 years! This OCI he used Ansoil Signature Series 5W30 oil. I don't know anything about Amsoils cleaning abilities, so anyone that does know, please educate me. I'm thinking he should use Pennzoil Platinum 5W30, or M1 5W30 next OCI @ 3K miles to clean it out even more. Opinions please? Thank You!