I just bought one that was "blowing coal". I replaced the IP, all of the 8 burned out glow plugs, the burned out glow plug relay, changed the engine oil, and properly filled the radiator. The kid that had it thought he was selling me a piece of junk, but I think I got a good truck after a little work, and stolen parts from my dead truck. It'll cost me a couple hundred dollars to get the IP re-set to proper settings, then rebuild the engine from my dead truck, and pickle it for further reference. The engine was over heating badly and slobbering coolant all over the place, besides using oil. Since making the repairs, not a drop of water use, and after a 220 mile trip at highway speeds used about a quart of oil.