The other 10-percent of the time, the EGR cooler plugs up with soot, carbon, and oil vapor deposits. Sadly, it’s not uncommon for an EGR cooler failure to be misdiagnosed, where only the EGR cooler gets replaced and the plugged oil cooler goes unaddressed- which predictably toasts the new EGR cooler in short order. Once that occurs, you’ve got coolant entering the exhaust (or even the intake) and copious amounts of white smoke leaving the tailpipe.
Because the coolant blockage in the oil cooler also starves the EGR cooler of the coolant it needs to function properly (remember, the EGR cooler is exposed to 1,200 degree EGT or more), the welds on its core eventually rupture.
Nearly 90-percent of all EGR cooler failures are a direct result of a plugged oil cooler. The general consensus is that both EOT and ECT should stay within 15 degrees of each other, but you should start watching things closely once a 10-degree difference between the two persists. Unfortunately, a failing oil cooler can go unnoticed for thousands of miles if you don’t have a way to precisely monitor engine oil temp and coolant temp simultaneously (the dummy gauges in the factory cluster won’t suffice). Once coolant flow through the oil cooler stops, oil temps sky-rocket. In blown head gasket scenarios, where combustion gases are allowed to enter the coolant, carbon contaminates also become lodged in the oil cooler’s tiny passages. This debris is made up of casting sand from the block or suspended deposits from using the incorrect coolant for the engine. The miniscule coolant passageways within the oil cooler are prone to clogging due to debris present in the cooling system.
Throw in an inability to effectively cool the oil and, sooner or later, you’ve got serious problems. With the 6.0L’s HEUI injection system pressurizing the engine oil as high as 3,600 psi in stock form (and 4,000 psi or more in high horsepower applications), some pretty serious heat gets generated. It’s notorious for its internal coolant passages clogging and blocking the coolant flow that’s vital for keeping engine oil temperature in check. It’s the stacked plate heat exchanger portion of the oil cooler assembly that wreaks the most havoc on the engine. No, it’s not the EGR cooler and no, it’s not the head bolts. You’re looking at the biggest failure point on the 6.0L Power Stroke. We’ll conclude with a list of must-have upgrades that no 6.0L Power Stroke should be forced to live without. Fortunately for all of us in 2020, 99-percent of the 6.0L’s problems have been thoroughly documented by mechanics and addressed by the diesel world’s thriving aftermarket. In the following pages, we’ll walk you through all of the 6.0L’s common failure points, starting with the most prevalent offenders. To be fair, some 6.0L’s do go the distance, but it’s very rare to find one with a quarter-million miles on the clock and no history of at least some sort of significant repair. Exhaust gas recirculation system, oil cooler, head gasket, injector, high-pressure oil pump, FICM, and turbocharger issues all run rampant-several of which strike within the first 100,000 miles You can virtually point to any component on the 6.0L other than its rotating assembly and associate some form of poor engineering or premature failure with it. Rumor has it that Ford even entertained the idea of buying Duramax engines from GM for use in its trucks during this timeframe… Powerful, yes. Thousands of roadside repairs, expensive tow bills, and repeat failures plague the ’03-’07 Super Duty’s. Perhaps no other diesel engine in recent memory has burdened its owners more than the 6.0L Power Stroke.