In the diesel performance world, Ford 6.0L Power Stroke engines have a bad reputation for blowing head gaskets and sticking EGR valves when owners modify them. There are a number of reasons why people have problems with their modified 6.0Ls, but one of the main culprits is the exhaust gas recirculation (EGR) system.
WHAT IS EGR?
Exhaust gas recirculation (EGR) is a system of plumbing and valves on a gasoline or diesel engine that sends burnt exhaust from the engine back into the intake side of the motor to be consumed again. Theoretically, because EGR has already been combusted once, it has no oxygen or fuel in it to be burned again.
Engine designers use EGR as a tool to reduce the amount of nitrogen oxides (NOX) emissions that an engine produces. Nitrogen oxides come from high-combustion chamber temperatures. Yet, when EGR is introduced into the engine, it tends to displace the amount of oxygen available to burn. This lowers the combustion chamber temperatures and the amount of NOX coming out of the tailpipe.
EGR NEEDS TO BE COOLED
For all intents and purposes, EGR is exhaust gas, exactly what you'd expect to see and smell coming out of your truck's exhaust system. It comes out of the engine hot. So before it is routed back into the intake, it is generally cooled with a heat exchanger connected to the engine's cooling system. Keep in mind that if the engine has been modified, the exhaust exiting the engine may be hotter than it should be. Plus, if there is any unburned fuel or oil in the exhaust, it'll wind up in the EGR system too.