and not just chunks, but small stones: Hard, abrasive, iron oxide rocks.
I thought I'd share something new I just learned about the lowly EGR cooler.
The cast iron EGR coolers can internally rust to the point that they'll eventually cough out disturbingly sized chunks of rust "stones" that will get blown into the EGR valve when it's active. These little traveling rust rocks can jamb the EGR valve open.
The chunks that don't get stuck in the EGR valve (and the big ones will) will get sucked into the engine and bounce around in there, doing who knows what, until they either get pulverized into smaller pieces to grind on things unknown, or spat out the exhaust port and lodged into the cat.... where eventually they'll burn up.
None of this sounds very pleasant, at least not to me.
On a fully functioning smog equipped engine, the active EGR system heats up the EGR cooler every time the engine is driven. It gets really hot. If the engine is driven at least every once in a while, the heat and soot keep the inside of the EGR cooler essentially rust free. Moisture never has a chance to create any significant internal corrosion.
But-
Some guys who have to run the biannual smog test gauntlet will temporarily disconnect the EGR valve either for smoother acceleration or because it's unreliable... only to hook it back up again for 30 minutes every two years.
It's this activity of installed disuse, that eventually, inexorably, destroys the innards of the EGR cooler.
After maybe a decade or so of doing this, (installed disuse) the inside of the EGR cooler can end up being more of an evil chunk spewing, EGR clogging, engine grinding rust bomb than the benign heat sink that it was designed to be.
It will also have to be replaced.
If the EGR cooler never gets blown out regularly with super heated exhaust gases, it rusts inside. It gets saturated with water vapor at every start up when the engine is blowing steam and that water on cast iron slowly but surely converts the metal into hard, abrasive chunks of rust that will break off and end up inside the engine.
Wanna see some pics?
These cute little monsters were jammed inside the EGR valve, preventing it from closing. I wonder how many other equally cute ones got sucked into the engine.....
I thought I'd share something new I just learned about the lowly EGR cooler.
The cast iron EGR coolers can internally rust to the point that they'll eventually cough out disturbingly sized chunks of rust "stones" that will get blown into the EGR valve when it's active. These little traveling rust rocks can jamb the EGR valve open.
The chunks that don't get stuck in the EGR valve (and the big ones will) will get sucked into the engine and bounce around in there, doing who knows what, until they either get pulverized into smaller pieces to grind on things unknown, or spat out the exhaust port and lodged into the cat.... where eventually they'll burn up.
None of this sounds very pleasant, at least not to me.
On a fully functioning smog equipped engine, the active EGR system heats up the EGR cooler every time the engine is driven. It gets really hot. If the engine is driven at least every once in a while, the heat and soot keep the inside of the EGR cooler essentially rust free. Moisture never has a chance to create any significant internal corrosion.
But-
Some guys who have to run the biannual smog test gauntlet will temporarily disconnect the EGR valve either for smoother acceleration or because it's unreliable... only to hook it back up again for 30 minutes every two years.
It's this activity of installed disuse, that eventually, inexorably, destroys the innards of the EGR cooler.
After maybe a decade or so of doing this, (installed disuse) the inside of the EGR cooler can end up being more of an evil chunk spewing, EGR clogging, engine grinding rust bomb than the benign heat sink that it was designed to be.
It will also have to be replaced.
If the EGR cooler never gets blown out regularly with super heated exhaust gases, it rusts inside. It gets saturated with water vapor at every start up when the engine is blowing steam and that water on cast iron slowly but surely converts the metal into hard, abrasive chunks of rust that will break off and end up inside the engine.
Wanna see some pics?
These cute little monsters were jammed inside the EGR valve, preventing it from closing. I wonder how many other equally cute ones got sucked into the engine.....
