When it comes to diesel engines, there’s probably nothing more polarizing than the 6.0-liter Ford Power Stroke. The 6.0-liter was first introduced in 2003 and was succeeded by the 6.4-liter in 2008. Though the 6.0-liter had a number of slight improvements over its lifespan, it was still plagued with many issues that varied from minor nuisances to catastrophic engine failures. All of these problems gave the 6.0-liter a horrible reputation and resulted in huge lawsuits against the Blue Oval.
Amazingly though, through all of the troubles, the 6.0-liter has proven to be quite a powerhouse. It has developed a massive following with enthusiasts that know how to make these engines come to life. One of the first products to come to market to address a major failure of the 6.0-liter was the Bullet Proof Diesel exhaust gas recirculation (EGR) cooler. The original Power Stroke EGR cooler had a very high failure rate and unfortunately, when they failed, they caused major engine damage.
It has been 15 years since the first 6.0-liter Power Stroke left the factory, and there are still thousands that have not been upgraded with an aftermarket EGR cooler. This includes our 2005 Excursion that has clocked over 180,000 miles. We certainly have no interest in continuing to drop money down the drain, so we are investing in many of the needed upgrades to make our Excursion more reliable and more powerful than the factory ever did. Probably the easiest and most cost-effective upgrade is an aftermarket EGR cooler.
A Closer Look
To understand why the EGR cooler plays such a significant role in causing engine failures, we first needed to find out what exactly is causing the EGR coolers to fail. At a basic level, we know that the EGR coolers receive hot exhaust gases and then cool them before they are recirculated back into the intake manifold. We also know that the coolers use engine coolant to help transfer that heat.
What we don’t know, is why 6.0-liter Power Strokes are plagued with EGR cooler issues when other engines aren’t. To get an expert’s knowledge on the situation, we spent some time talking with Jeff Dahlin at Bullet Proof Diesel. Surprisingly, the factory EGR cooler isn’t as much at fault as we thought; although the factory design certainly leaves it vulnerable to adverse conditions and resulting failures.
“The radiator-like finned core of an OE EGR cooler quickly heats up if it’s not bathed in coolant,” said Dahlin. “If there’s some ‘thermal event,’ such as not enough coolant in the vehicle, or for whatever reason the EGR cooler isn’t filled with coolant, you get heat expansion of the core. This heat expansion pushes the inner core outward at both ends. Eventually, the endplates (also called ‘bulkheads’) are pushed out by the core, and an EGR cooler rupture develops.”
So, basically, the EGR cooler fails when there’s a loss of coolant flow. Understanding this led us to the next question: What’s causing the loss of coolant? “In the 6.0-liter, this usually happens when the stock oil cooler gets plugged up,” explained Dahlin. “It’s a stacked-plate heat exchanger with alternating rows of coolant and oil. Often, debris in coolant can eventually plug up the oil cooler. When this happens, the EGR cooler (which comes after the oil cooler in terms of coolant flow) doesn’t get coolant, and the expansion/rupture follows quickly afterward.”
Given that a clogged oil cooler is likely the underlying cause of an EGR cooler failure, we couldn’t help but wonder: why not just spend our money on an aftermarket oil cooler and stick with a factory EGR cooler? Or just delete/plug the EGR cooler and not use it at all? “There are a number of other causes of ‘thermal shock’ to EGR coolers, and the Bullet Proof Diesel EGR cooler protects against them,” said Dahlin. “Low coolant levels in a vehicle, a coolant leak, air bubbles in the coolant lines, or other causes can allow the stock EGR cooler to experience metal expansion, which ruptures the EGR cooler from inside out.”
“The Bullet Proof Diesel EGR cooler is a fundamentally different design than OE,” continued Dahlin. “Rather than finned passageways like the OE version, we build the EGR core using tubes. These tubes are braided in a helical pattern within the EGR cooler. This allows much of the tube expansion to happen laterally when a thermal event occurs, putting far less stress on the endplates of the unit. As a result, rupture situations are so rare with the upgraded EGR coolers that Bullet Proof Diesel places a lifetime parts warranty on them.”
Deleting the EGR cooler is a somewhat popular alternative, but can have negative consequences and is technically illegal in all states. Even though in most states, we can delete our EGR cooler without worrying about smog, it’s still very important that the EGR valve stays functional. The EGR valve plays a role in the cooling system clutch fan and having it disconnected can cause heating issues.
Of course, in California, where we are, a 6.0-liter will not pass smog with a deleted EGR cooler. In fact, California has figured out a way to detect a deleted or plugged EGR cooler through the OBD-II port, even with no check engine light (CEL). This is due to the new parameters that California looks at within the EGR system. The PCM (powertrain control module) goes through an EGR system monitor readiness test as the truck is driven. This determines if all the sensors and components are functioning correctly.
Once enough drive cycles are gone through, the PCM will either show complete or continue to be incomplete. This is when the PCM will set the CEL. Some aftermarket tuners can stop the CEL from coming on. However, they can’t stop the PCM from reading incomplete on the monitor readiness test. This is why tuners can no longer be used in California to delete or bypass an EGR cooler. With all the negatives of deleting the EGR cooler, it only made sense for us to simply upgrade ours and be legal.
Installing the Bullet Proof EGR cooler is a big job but not a complicated one. There are many components that need to be removed just to get to the EGR cooler including the intake manifold. We’ve found that if we weren’t in a hurry the job went smoothly. However, whenever we got a little rushed or put a timeline on getting it done, things went south quickly.
Even though our engine didn’t have too many miles on it since the last time it was apart, it still had collected a lot of dirt and gunk. Most of the dirt built up on the bottom side of the components creating a big mess when they were removed. We sprayed and cleaned the best we could but still made sure we taped off the fuel lines and any other ports as soon as they were exposed.
Once we got everything out of the way the manifold was ready to come out. The EGR cooler came out with the intake manifold and will go back in the same way. Last time we had it apart we decided to try the cheap route and just plug the factory style EGR cooler. We left the coolant passage open and just plugged both sides where the exhaust enters and exits. This allowed the stock EGR cooler to be placed back in the engine with the coolant flow undisturbed. When we drilled into the plug on the exhaust side we were surprised to see that it had been leaking. The exhaust side of the EGR cooler was full of coolant and would have likely caused severe engine damage if we hadn’t plugged it and didn’t catch it in time. With the new Bullet Proof EGR cooler, we shouldn’t ever have to worry about a failure again. Their patented core design allows Bullet Proof Diesel to offer a full lifetime warranty.
The new Bullet Proof Diesel EGR cooler bolts on in the exact location as the old cooler. Since all the bolts go through the top of the manifold we were able to get it fitted first on the intake manifold. Then once the manifold was bolted in and the EGR cooler was connected to the exhaust we tightened it the rest of the way.
To finish the job all of the components needed to go back in the same way they came out. We also had to replace the aftermarket up pipe with the factory version so exhaust would be routed into the EGR cooler. One difficult part of the job is getting the exhaust flanges to match up correctly. We found that loosening them up from underneath gave the pipes enough movement to allow the proper fitment. The band clamps won’t bring the pipes together if they are misaligned so it was important to get the gaps tight prior to tightening the clamps.
We have been driving the Excursion daily for at least a couple weeks since the Bullet Proof Diesel EGR cooler install. We fortunately passed smog with no issues, although it took some time for the EGR system to complete its tests. Even though we went from a deleted EGR cooler to adding one back in, we’ve felt no real change in performance.
The 6.0-liter makes a ton of power even with an EGR cooler. If you want to be smog-legal and not worry every two years, then it’s worth your time to upgrade to a Bullet Proof Diesel EGR cooler. It’s a single-time investment that can save your engine from catastrophic failure, and keep your 6.0-liter passing at the smog station.