? 10w40 for a higher milage motor?
i have a 99 xj with the i6. its got 171450 miles. a friends dad suggested that when i get my oil changed at 171500, i should switch from 10w30 to 10w40. said the thicker oil will help preserve my engine; and that he had put 10w40 in his 70 bronco for that reason. wats you thoughts? should i switch or no?