Just do what I usually do. I tell them to bring it back with a six pack and a cam cover gasket when it hits 600 miles. I also tell them if they do not and it fails, its all on them and I won't feel the least bit sorry for them. Of course I tell them this after I have been paid, but most will go ahead and bring it back and seem to appreciate the "after service". I also give them the "old cars are like old people" lecture and wish them luck.
