I have a 1991 ford ranger 4x4, 4.0 v6. 190,000 miles. Runs great and even gets 18-20 mpg on hwy trips with a 1200lb camper. I have been using small amounts of antifreeze for the passed year with no leaks. Lately much more, sometimes a 1/4 gallon in 400 miles. 4,000 miles ago was having a miss...