From Bob McDonald. If there was an engine that plagues the midsize diesel world, that would have to say that it is the 6.0L Power Stroke.
This engine has the worst repair history that has plagued and continues to plague Ford truck owners today. Even though the engine was only produced from 2003 to 2008, truck buyers often shy away from these engines when purchasing a diesel truck. You can find more information about 6.0 Turbo Rebuild in here.
A comment often heard is: “Why did International stop producing the 7.3L engine?”
Well, there are some areas that need to be covered as to why the 6.0L came into existence and some remedies for problems that have absolutely ruined Ford’s truck reputation for this model year.
6.0L origins
The 6.0L came into existence because the EPA required stricter emissions laws for diesel engines. Even though the 7.3L was billed as the reliable workhorse for Ford, it would never be able to pass the stricter emissions laws that were to go into effect for 2004.
In saying that, I often feel that owners of 7.3L Power Stroke engines don’t realize that their engine was designed to be emissions compliant as well.
This is why the HEUI 7.3L design was released in 1994.
Stronger emission laws went into effect in the mid-90s, so they were at the forefront of the game in terms of emission compliance and having a very reliable engine with the 7.3L.
This was one of the reasons these engines were equipped with a catalytic converter.
To meet 2004 emission standards, the EPA requires cleaner diesel engines. These standards mean that less nitrogen oxide emission levels than diesel could be released into the air.
For International Development, this was the beginning of the snowball that will slowly begin its descent down the long hill.
The only way to reduce emissions was to use an EGR (Exhaust Gas Recirculation) valve and come up with a more efficient engine. Saying this, you have to realize that the 7.3L was a good engine, but it wasn’t very efficient.
As soon as an EGR valve is installed in a diesel engine, the power drops off quite quickly. If you are wondering why, let me explain.
EGR issues
When an EGR valve is incorporated into a diesel engine, the object is to bring the exhaust gas back into the intake manifold to be re-burned.
When the exhaust gas enters the intake manifold, it has displaced the oxygen that was being brought in from the outside air for combustion.
So the combustion temperature drops because there was no complete burn. This in turn causes soot, which starts clogging everything.
But, before you can introduce the exhaust gas into the intake manifold in a diesel engine, you have to cool down.
Under a load, diesel exhaust gas temperatures can reach as high as 1,000 ° F or more. Thus, the exhaust gas travels through what is known as an EGR cooler.
This is a cooler that is distributed with the engine coolant, and is mounted under the intake manifold.
Exhaust gases travel out of the manifold through an opening in the tube, which then enters the cooler before exiting the intake manifold.
One of the problems that the 6.0L had was that the EGR cooler did not “live” very long. Over a period of time, the coolers would be removed from exposure to extreme heat.
When this happened, the antifreeze leaked into the exhaust system causing steam. Many times, owners would often realize this when stopped at a stoplight.
The clouds of water vapor passing by them while they were waiting for the traffic light to change.
Owners would often notice a puddle of antifreeze under the vehicle after it has been parked for several hours. Sometimes you ignore the EGR cooler leak and continue driving the vehicle until one day the engine won’t turn over.
What would happen was the coldest it seeped into the exhaust system overnight.
The leak would be so bad that the exhaust manifolds fill with coolant, which would go into a cylinder with an open exhaust valve.
This would cause the engine to hydro-lock, which could bend a connecting rod when attempting to start the engine.
Turning on the Power Stroke
The stakes were high for International Development. Not only did he build a smaller engine that was more efficient and capable of carrying an EGR valve, but he also had to do it for power.
Customers don’t want an engine with less power. Therefore, the 6.0L was a great achievement compared to the 7.3L. It is still a HEUI design, but now it has four valves per cylinder.
The combustion chambers in the pistons have been redesigned along with the addition of a VGT (Variable Geometry Turbo).
By making a smaller package, you tend to lose space for your bras. When redesigning the HEUI engine, the cylinder heads went from six head bolts per cylinder to four.
Which shouldn’t be a problem, but the engine faces a lot of boost, especially if a programmer is installed.
The VGT was designed to use boost throughout the rpm range.
If you recall, the 7.3L made great low down torque and would have no boost until the engine was in the rpm range. With the small 6.0L, in order to make power down, it had to make more boost to propel the engine.
This would prove to be a problem with four cap screws per cylinder.
The bolts in question are called torque-to-performance, which means that when properly tightened, they will stretch to the correct limit and hold the joint.
But what happens when a high level of momentum is forced on the engine, stretching the bolts too far?
It ends with a screw that is overloaded that loosens the head gasket and causes a leak.
So one of the many problems a head gasket leak had. Just because you may have had to change once does not mean that you would not have to change again.
