OK now the tank is down enough to show less than full and the regurgitating hasn't recurred in about two days. I am afraid to take the cap off, though :-) If the tank was overfilled, was it my fault? Is there something I need to look into maintenance-wise that could have caused it to overfill? It looks like there is an expansion tank associated with my fuel tank and this did happen during very hot weather. Is it possible that the expansion tank is holding fuel when the main tank is low?

Also, as a side note, it looks like I just ordered a new Nissens radiator that is the wrong part number and if I can't stop the shipment in time does anyone with a 1981- 123 300 diesel need a new radiator?