Originally Posted by gbickel
Replaced the fuel filters because customer did not think they were ever changed. The were new but we changed them any way. It has 45 psi fuel pressure.
You not only have to replace the oil cooler and the egr cooler, you must replace the fuel pressure regulator spring.
45psi is not nearly enough pressure, and left the way it is, injectors will be damaged.
The kit for the newest update for the fuel pressure regulator spring part number and intimate detailed instruction on how to replace it
is already right here on this forum. Very well written piece by Band_Member.
The reason you must replace both the oil cooler and EGR cooler is that the oil cooler is plugged on the coolant side of it. That has slowed the coolant flow to the EGR cooler. That overheats the EGR cooler to the point of failure. The coolant could be flowing down the up-pipe on the passenger side of the truck right now, filling the cylinders that have the exhaust valves in the open position, Hydrolocking the engine.
What this all has to do with the buzz test is beyond me. But those issues should be addressed previous to turning that key again. The customers head gaskets may depend on it. They may have already popped.