Got a fella in camp with a 7.3 that has 479,000 miles. It won't start. It smokes out the pipe when he cranks it. I have already talked to him about my opinion. He disagrees. He just keeps charging t...
Geez I hope he got more than just a glow plug relay for $500.
With that many miles though, if the valve cover gaskets and "under valve cover" glow plug/injector wire harnesses have never been touched I can guarantee you they need to be replaced. Tell him to unplug each of the external connectors on the valve cover gaskets and look for any signs of burning or melting. The connections under the valve covers will be in even worse shape.