VEHICLE: 2003 Ford Super Duty pickup truck
MILEAGE: 2,500 miles
DRIVETRAIN: 6.0L Power Stroke engine, Torqshift trans.
COMPLAINT: Engine stalled, won’t restart.Whenever I buy a vehicle for my own personal use, I choose one of the tried-and-true platforms that have been around for a while. Most of the bugs have been worked out of a vehicle package that has been out for a few years. In 1993, I bought a new Tempo. Five years later, I bought a 1995 Taurus and then this past year, a 2001 Jeep Cherokee. Each choice was made because I knew the bugs had been worked out of those respective cars. I had worked on Tempos since they were introduced in the early ’80s and had noticed that the last generation of that car seemed particularly dependable. I wasn’t disappointed. With the exception of a noisy harmonic balancer, the Tempo needed very little service during the time we owned it. I had been carefully observing the venerable old Taurus for more than a decade, and had seen it undergo a number of really positive changes since its introduction in 1986. Taurus underwent a total overhaul in the 1996 model year, and I knew I wanted a ’95 model. Sure enough, all the bugs were gone. When I sold the vehicle to my oldest son, the odometer had seen 180,000 miles with very little unscheduled maintenance, and it still runs and drives as well as when I bought it. The Jeep Cherokee joined the ranks of extinct vehicles at the end of the 2001 model year. It was replaced by the Liberty, which, by the way, seems to be a really solid little machine in spite of its ‘newness.’ However, I knew the Cherokee and liked it, so it became my latest choice.
MILEAGE: 2,500 miles
DRIVETRAIN: 6.0L Power Stroke engine, Torqshift trans.
COMPLAINT: Engine stalled, won’t restart.Whenever I buy a vehicle for my own personal use, I choose one of the tried-and-true platforms that have been around for a while. Most of the bugs have been worked out of a vehicle package that has been out for a few years. In 1993, I bought a new Tempo. Five years later, I bought a 1995 Taurus and then this past year, a 2001 Jeep Cherokee. Each choice was made because I knew the bugs had been worked out of those respective cars. I had worked on Tempos since they were introduced in the early ’80s and had noticed that the last generation of that car seemed particularly dependable. I wasn’t disappointed. With the exception of a noisy harmonic balancer, the Tempo needed very little service during the time we owned it. I had been carefully observing the venerable old Taurus for more than a decade, and had seen it undergo a number of really positive changes since its introduction in 1986. Taurus underwent a total overhaul in the 1996 model year, and I knew I wanted a ’95 model. Sure enough, all the bugs were gone. When I sold the vehicle to my oldest son, the odometer had seen 180,000 miles with very little unscheduled maintenance, and it still runs and drives as well as when I bought it. The Jeep Cherokee joined the ranks of extinct vehicles at the end of the 2001 model year. It was replaced by the Liberty, which, by the way, seems to be a really solid little machine in spite of its ‘newness.’ However, I knew the Cherokee and liked it, so it became my latest choice.
Unlike the old 7.3L rail, this one is removable. The oil feeds the injectors from the top in-stead of the side, reducing the number of O-rings necessary on the injector body.
Here’s the passenger side injector bank with the oil rail removed. And while Marty had plainly seen fuel dripping from most of the injectors, it wasn’t evident yet exactly where all the fuel was coming from.
With a 50/50 mix of diesel fuel and engine oil for lubrication, this poor turbocharger didn’t stand a chance when spinning at speeds near 100,000 RPM.
Shooting through the yellow glasses under a black light, these dye trails told the tale.
Each injector had dye puddled at the vent hole above the case nut and below the solenoid body.
The bright pink area in this cutaway injector shows the fuel chamber. For the fuel to work its way from this area to the apparent leak points, it would have to make its way past a lot of carefully machined and fitted parts. It appears that the injectors may have O-rings that were omitted from this cutaway model.In all the years I worked for a Ford dealer, I could never understand why some of the dealership employees would buy a competitive make vehicle and then rush it into our service department at the first sign of a problem. It’s good to know how to fix just about any make and model, but let’s face it: A Chrysler guy might be a really accomplished diagnostician on the DC line, but he might fall flat on his face when presented with a Pontiac or a Toyota. But even with factory training and hotline assistance, diagnosis on any new engine or vehicle platform can generate honest mistakes that will make even the most conscientious technician look and feel silly.The new 6.0L
When I met Motor Age Technical Editor Jacques Gordon in Indiana to visit the Navistar Engine Plant last year, he and I were both measurably impressed at the company’s commitment to quality, the cleanliness of the plant and the rigid standards to which the new 6.0L Power Stroke was being tested. There were more than 20 quality control test areas each engine had to pass during the assembly process. For instance, for the first few months of production, literally every engine that came off the line was being started and run for 18 seconds. The hydraulic (fuel and oil) and electrical systems were carefully checked for leaks and shorts respectively. Navistar and Ford were dead serious about building a dependable engine that would measure up to the exacting standards set by the trusty 7.3L.But no matter how carefully each engine is checked for quality in the plant, one weak link in the chain can lead to disaster. And this month’s story proves that sometimes there are problems that simply won’t be discovered until they have been in the field for a few months.Dead in the water
There are very few line technicians I have ever known that I respect as much as my friend Marty. We all make mistakes from time to time, but Marty’s professionalism, honesty and candor are a hard act to follow. And his deep understanding of engines and what it takes to fix them makes guys of his mettle indispensable in a world where there are two to three thousand cars on the road for each qualified technician.The Power Stroke specialist was sick with a virus; he would ordinarily have drawn the repair order on the 6.0L in question when the Super Duty came in on the hook. But he was out, and Marty drew the ticket. The truck had begun losing power, then finally stalled and refused to restart. Marty’s initial inspection revealed a bad turbocharger. The turbine shaft was wallowing around on wiped out bearings, and that in itself seemed strange with only 2,500 miles. The truck wasn’t even due for an oil change yet. Marty replaced the bad turbocharger, and when he started the engine it seemed to run normally. He took the truck on a test-drive, and after only a few miles he began experiencing similar symptoms: stalling, power loss, etc. Working his way back to the shop with an engine that no longer wanted to run was quite an adventure. It stalled twice at traffic lights, and each time Marty had to grind on the starter for almost a minute to get it started again.Seven gallons in the crankcase
Marty pulled the dipstick and found that the crankcase was ridiculously overfull with something that felt more like diesel fuel than engine oil. Draining the crankcase and measuring the contents, he reached the conclusion that every quart of engine oil had been joined by a quart of diesel fuel. A normal crankcase drain would produce 3.5 gallons of oil. This 6.0L crankcase gave up no less than seven gallons of liquid when the drain plug was removed.
You don’t have to be Phi Beta Kappa in engine repair to understand that a 50/50 mix of engine oil and diesel fuel makes a lousy lubricant. The engine bearings probably didn’t suffer enough to matter, but turbocharger bearings – carrying a turbine/impeller shaft spinning at speeds approaching 100,000 rpm – won’t survive. With diluted engine oil, Marty’s test-drive destroyed the second turbocharger in a mere seven miles. This vile concoction was also giving the oil control system fits, probably producing massive amounts of foam, which would explain the stalling as the engine heated up.So, where’s the leak?
Marty was as candid and honest as ever. He was quick to admit that he should have paid more attention to the engine oil, but that wasn’t the point at this juncture. What we all needed to know was how all that fuel was making its way into the crankcase so fast. Do the math: 14 quarts in 25 hundred miles equates to about a pint every hundred miles; that’s no small leak, and it should be easy to find, right? Wrong.The most probable place where a leak of this type would occur is under the valve cover, past the injector O-rings. The new 6.0L injectors receive their control oil charge through the top of the injector instead of through the cylinder head, and as a result, the fuel chamber O-rings on these injectors are only a fraction of an inch from the crankcase oil splash under the valve cover. At first consideration it seemed that there must have been a poor O-ring seal or a poorly machined sealing surface on one of the eight injectors, which could allow a large quantity of fuel to find a leak path into the lube oil.Uncovered
Marty’s next step was to remove the valve covers in an attempt to find the fuel leak. To remove the passenger side valve cover, the shop manual calls for the A/C evaporator case to be removed, but a tech like Marty, with his robot arms and ratchet wrists, managed to work it out of there without doing all that. Product variability in the field, however, might make it necessary to pull the evaporator case on other vehicles. With dye added to the fuel supply, the injectors laid bare and the fuel system pressurized, no leak was apparent, but the engine was cool at the time. Adding air pressure to the fuel rail and checking for bubbles produced no results either.After plugging in the block heater and letting it heat the engine to the point where the injectors were warm to the touch, Marty’s black light found pay dirt. With the fuel system pressurized and the engine warm but not running, six of the eight injectors were dripping fuel into the crankcase. But because of the way the injectors are mounted, it was extremely difficult to determine the source of the leaks.When Marty called the Ford Hotline, one of the engineers had mentioned the possibility of fuel leaking inside the injector from the injector’s fuel supply chamber into the injector’s oil chamber – a theory that made no sense at all to begin with. Since a leak path would naturally travel from the point of high pressure (oil rail pressure runs from 500 to 3000 pounds) to low pressure (60 pounds fuel pressure), how could the fuel leak into the high-pressure oil rail? The conclusion was that the fuel was indeed leaking from within the injectors, not into the high-pressure oil gallery, but into the low pressure of the crankcase.Removing the injectors and applying the black light, there appeared to be two leak points on most of the injectors. One concentrated pool of fuel was clustered under the closing solenoid on each injector. Another leak point appeared to be at the vent hole between the case nut and the intensifier piston housing. Studying the cutaway view of the injector, it seems that the fuel must have found a leak path past the machined components to the outside of the injector.Eight new nozzles
Marty obtained warranty authorization, replaced the turbocharger again and installed eight new nozzles. The final test-drive went fine.The fuel leak on this engine was obviously missed during the factory quality control tests because the engine wasn’t warm. Even if the engine had been at operating temperature, 18 seconds of run time wouldn’t have revealed the dripping injectors. No amount of factory examination can match prevailing conditions and operational variations in the field, not even laboratory testing.And on a 7.3L …
The Power Stroke specialist had a 7.3L consuming large amounts of engine oil – three quarts in less than 200 miles, as a matter of fact. At the end of his long battery of tests, Eddie found three injectors delivering
copious amounts of engine oil to the combustion chamber. When he pulled the injectors, the nozzles
were actually leaking oil. He replaced all eight. As Power Stroke HEUI injectors are remanufactured again and again, new problems like this are likely to surface. If you’re a Power Stroke kind of a guy, it’s obviously a good idea to pay close attention to the nozzles and think outside the box. Shop manual troubleshooting procedures won’t always lead to the solution.
When I met Motor Age Technical Editor Jacques Gordon in Indiana to visit the Navistar Engine Plant last year, he and I were both measurably impressed at the company’s commitment to quality, the cleanliness of the plant and the rigid standards to which the new 6.0L Power Stroke was being tested. There were more than 20 quality control test areas each engine had to pass during the assembly process. For instance, for the first few months of production, literally every engine that came off the line was being started and run for 18 seconds. The hydraulic (fuel and oil) and electrical systems were carefully checked for leaks and shorts respectively. Navistar and Ford were dead serious about building a dependable engine that would measure up to the exacting standards set by the trusty 7.3L.But no matter how carefully each engine is checked for quality in the plant, one weak link in the chain can lead to disaster. And this month’s story proves that sometimes there are problems that simply won’t be discovered until they have been in the field for a few months.Dead in the water
There are very few line technicians I have ever known that I respect as much as my friend Marty. We all make mistakes from time to time, but Marty’s professionalism, honesty and candor are a hard act to follow. And his deep understanding of engines and what it takes to fix them makes guys of his mettle indispensable in a world where there are two to three thousand cars on the road for each qualified technician.The Power Stroke specialist was sick with a virus; he would ordinarily have drawn the repair order on the 6.0L in question when the Super Duty came in on the hook. But he was out, and Marty drew the ticket. The truck had begun losing power, then finally stalled and refused to restart. Marty’s initial inspection revealed a bad turbocharger. The turbine shaft was wallowing around on wiped out bearings, and that in itself seemed strange with only 2,500 miles. The truck wasn’t even due for an oil change yet. Marty replaced the bad turbocharger, and when he started the engine it seemed to run normally. He took the truck on a test-drive, and after only a few miles he began experiencing similar symptoms: stalling, power loss, etc. Working his way back to the shop with an engine that no longer wanted to run was quite an adventure. It stalled twice at traffic lights, and each time Marty had to grind on the starter for almost a minute to get it started again.Seven gallons in the crankcase
Marty pulled the dipstick and found that the crankcase was ridiculously overfull with something that felt more like diesel fuel than engine oil. Draining the crankcase and measuring the contents, he reached the conclusion that every quart of engine oil had been joined by a quart of diesel fuel. A normal crankcase drain would produce 3.5 gallons of oil. This 6.0L crankcase gave up no less than seven gallons of liquid when the drain plug was removed.
You don’t have to be Phi Beta Kappa in engine repair to understand that a 50/50 mix of engine oil and diesel fuel makes a lousy lubricant. The engine bearings probably didn’t suffer enough to matter, but turbocharger bearings – carrying a turbine/impeller shaft spinning at speeds approaching 100,000 rpm – won’t survive. With diluted engine oil, Marty’s test-drive destroyed the second turbocharger in a mere seven miles. This vile concoction was also giving the oil control system fits, probably producing massive amounts of foam, which would explain the stalling as the engine heated up.So, where’s the leak?
Marty was as candid and honest as ever. He was quick to admit that he should have paid more attention to the engine oil, but that wasn’t the point at this juncture. What we all needed to know was how all that fuel was making its way into the crankcase so fast. Do the math: 14 quarts in 25 hundred miles equates to about a pint every hundred miles; that’s no small leak, and it should be easy to find, right? Wrong.The most probable place where a leak of this type would occur is under the valve cover, past the injector O-rings. The new 6.0L injectors receive their control oil charge through the top of the injector instead of through the cylinder head, and as a result, the fuel chamber O-rings on these injectors are only a fraction of an inch from the crankcase oil splash under the valve cover. At first consideration it seemed that there must have been a poor O-ring seal or a poorly machined sealing surface on one of the eight injectors, which could allow a large quantity of fuel to find a leak path into the lube oil.Uncovered
Marty’s next step was to remove the valve covers in an attempt to find the fuel leak. To remove the passenger side valve cover, the shop manual calls for the A/C evaporator case to be removed, but a tech like Marty, with his robot arms and ratchet wrists, managed to work it out of there without doing all that. Product variability in the field, however, might make it necessary to pull the evaporator case on other vehicles. With dye added to the fuel supply, the injectors laid bare and the fuel system pressurized, no leak was apparent, but the engine was cool at the time. Adding air pressure to the fuel rail and checking for bubbles produced no results either.After plugging in the block heater and letting it heat the engine to the point where the injectors were warm to the touch, Marty’s black light found pay dirt. With the fuel system pressurized and the engine warm but not running, six of the eight injectors were dripping fuel into the crankcase. But because of the way the injectors are mounted, it was extremely difficult to determine the source of the leaks.When Marty called the Ford Hotline, one of the engineers had mentioned the possibility of fuel leaking inside the injector from the injector’s fuel supply chamber into the injector’s oil chamber – a theory that made no sense at all to begin with. Since a leak path would naturally travel from the point of high pressure (oil rail pressure runs from 500 to 3000 pounds) to low pressure (60 pounds fuel pressure), how could the fuel leak into the high-pressure oil rail? The conclusion was that the fuel was indeed leaking from within the injectors, not into the high-pressure oil gallery, but into the low pressure of the crankcase.Removing the injectors and applying the black light, there appeared to be two leak points on most of the injectors. One concentrated pool of fuel was clustered under the closing solenoid on each injector. Another leak point appeared to be at the vent hole between the case nut and the intensifier piston housing. Studying the cutaway view of the injector, it seems that the fuel must have found a leak path past the machined components to the outside of the injector.Eight new nozzles
Marty obtained warranty authorization, replaced the turbocharger again and installed eight new nozzles. The final test-drive went fine.The fuel leak on this engine was obviously missed during the factory quality control tests because the engine wasn’t warm. Even if the engine had been at operating temperature, 18 seconds of run time wouldn’t have revealed the dripping injectors. No amount of factory examination can match prevailing conditions and operational variations in the field, not even laboratory testing.And on a 7.3L …
The Power Stroke specialist had a 7.3L consuming large amounts of engine oil – three quarts in less than 200 miles, as a matter of fact. At the end of his long battery of tests, Eddie found three injectors delivering
copious amounts of engine oil to the combustion chamber. When he pulled the injectors, the nozzles
were actually leaking oil. He replaced all eight. As Power Stroke HEUI injectors are remanufactured again and again, new problems like this are likely to surface. If you’re a Power Stroke kind of a guy, it’s obviously a good idea to pay close attention to the nozzles and think outside the box. Shop manual troubleshooting procedures won’t always lead to the solution.
