How to Keep Your Power Stroke Diesel Alive and Healthy
How to Improve Powerstroke Reliability
Regular maintenance is important for any vehicle. Negligence will lead to poor performance and a premature end of service life. The Power Stroke diesel engine, if well maintained, can be a particularly reliable and useful engine, it is used in many demanding applications, including ambulances and service trucks and can provide hundreds of thousands to a million miles of effective service. So it is particularly important to keep up with the maintenance.
Following Ford’s recommendations and keeping an accurate vehicle service history will help prevent unnecessary problems in the long run.
Severe duty service intervals are a requirement, not a recommendation – If your driving activities include heavy towing, extended idling, short duration drives, or driving primarily in heavy traffic or dusty areas, your vehicle falls under the “Severe Duty” maintenance category, which requires more frequent service intervals. Understand and follow the maintenance schedule which properly reflects your driving conditions.
Power Stroke Reliability Tips
Change Oil and Oil Filter at the Correct Interval
Ford Power Stroke engine owners often change their oil and oil filter according to the service manual, which recommends 5,000 miles. But, the owner’s manual actually recommends four intervals at which the oil should be changed: 5,000 miles, 3 months, every 250 gallons of fuel or 200 engine hours, whichever comes first. Owners often focus on the 5,000 mile interval but often overlook the other three recommendations. One of the most critical of these is engine hours.
One hour of idle time, is equal to approximately 25 miles of driving.
Extended oil change intervals may cause injector damage that may lead to reduced performance, reduced durability and possibly component failure.
Consider switching to a synthetic engine oil
Synthetic motor oil is superior to mineral oil in many ways, including :
- Better low and high temperature viscosity performance at service temperature extremes
- Better chemical and shear stability
- Decreased evaporative loss
- Resistance to oxidation, thermal breakdown, and oil sludge problems
- Dispersants that help keep soot particles small and from collecting together, so they can flow in the oil and not cause damage.
- More detergents, which keep the engine free and clean from varnish and sludge
In the Power Stroke engine, the extreme pressures exerted on the oil via the high pressure system accelerates the effects of thermal and mechanical breakdown. Synthetic oil being more resilient to breakdown, helps to maximize protection between oil changes.
Fuel dilution occurs when small amounts of unburned fuel make it past the piston rings and into the oil. Diesel fuel and diesel oil blend well together but the down side is lower oil viscosity. If you are using a mineral based 15W40 oil, fuel dilution can eventually reduce the viscosity to an SAE 30 or even an SAE 20 level very quickly.
A drawback of synthetic oil is its price, which can be considerably higher than mineral based oils.
Clean, unrestricted air is vital to the performance of a Power Stroke diesel engine
Restricted air intake can lead to performance problems and increased Exhaust Gas Temperatures(EGTs), 7.3 Power Stroke engines can benefit greatly by using a Ford/Donaldson AIS severe duty intake system conversion Kit (which includes the FA1757 air filter).
The EGR (exhaust gas recirculation) valves and EGR coolers commonly fail and/or contribute to reliability concerns. The EGR valve can be easily cleaned and reinstalled with new o-rings. Become familiar with removing and cleaning the EGR valve rather than waiting for it to become clogged or stuck in one position. When the EGR valve clogs, your fuel economy and performance will suffer. Worse yet, a clogged EGR valve can cause an engine to run hotter than normal, which contributes to head gasket failures. Taking the extra half hour to service the EGR at least every other oil change is time well spent.
Clean Fuel Filters are Inexpensive Insurance
The least expensive part of the Power Stroke fuel injection system is the fuel filter. The fuel filters need to be changed every 15,000 miles. There are two filters, one engine mounted (in the fuel-water separator) and one chassis mounted The HEUI injection system is rather sensitive to dirty fuel and the filters are a fraction of the cost you could spend on injectors. Clogged fuel filters can damage expensive injection pumps and injectors. Diesel fuel injection systems create a great deal of heat, and they rely on unobstructed fuel flow to keep the pump and injectors cool.
Power Stroke Fuel Filter part numbers
7.3 Liter : F81Z-9N184-AA
6.7 Liter : BC3Z-9N184-B
6.4 Liter : 8C3Z-9N184-C
6.0 Liter : 3C3Z-9N184-CB
Drain Water Fuel / Water Separator
Diesel fuel attracts water – often from condensation. Water in the fuel can damage up your injectors as the water explodes into steam under extreme pressure – such as on the compression stroke of a diesel engine.
If you live in a humid climate, condensation is more likely. You can buy “bad diesel” that includes condensation, if you don’t buy all your diesel fuel from busy truck stops.
Don’t let the vehicle sit for extended periods with partially full fuel tank(s). The moisture content in the air in the tank becomes condensation, and if you keep the tank full of fuel, there’s less chance moisture will condense because there’s less air space in the tank.
Power Stroke engines have a fuel / water separator built-in to the fuel system, that makes it very easy to drain the separated water from your fuel system. If you get fuel with a little bit of water in it, due to condensation in the tank from either the source (fuel station) or your own fuel tank, the water separator will enable you to get the water out before it goes into the injectors. The water stays in the fuel filter until you drain it out. But if you don’t drain the fuel filter, and it gets full of water, then you could end up with damaged injectors. Have you priced fuel injectors for your engine lately? They are not cheap. Water damage to injectors won’t be covered by warranty.
The interval for draining the water from the fuel / water separator depends on the climate and the source of your diesel fuel, but it is better to remove the water before you have the water in fuel light illuminate.
Use a Quality Diesel Fuel Additive
Since 2006, almost all of the petroleum-based diesel fuel available in Europe and North America have been of a Ultra Low Sulfur Diesel(ULSD) type in order to lower emissions of particulate matter from diesel engines.
Sulfur is not a lubricant in of itself, but it can combine with the nickel content in many metal alloys to form a low melting point eutectic alloy that can increase lubricity. The process used to reduce the sulfur also reduces the fuel’s lubricating properties. Lubricity is a measure of the fuel’s ability to lubricate and protect the various parts of the engine’s fuel injection system from wear. The processing required to reduce sulfur to acceptable levels(15 ppm) also removes naturally-occurring lubricity agents in diesel fuel.
Diesel fuel quality in the U.S. is inconsistent and often doesn’t even meet manufacturer recommended cetane rating specifications. Ford recommends using a fuel additive that increases the cetane rating of diesel and provide additional lubrication to the fuel system. Motorcraft markets its own specifically for Ford diesels, but there are many quality, affordable brands on the market as well.
Stanadyne brand diesel fuel additives are the only ones in the world that are:
- Developed by a fuel injection systems manufacturer
- Tested and approved by major engine and vehicle manufacturers
- Proven to perform best in independent tests
Avoid Excessive Idling
Excessive idling is not going to enable your engine to get up to full operating temperature and it is going to contribute to fuel dilution of the engine oil. Because of this viscosity thinning, the engine is now at risk of not getting the proper lubrication and protection. In extremely cold weather, it may be necessary to let the engine idle for up to 10 minutes before driving. In warmer conditions, 2 to 3 minutes is completely adequate.
Putting the engine under load by driving is always necessary for the engine to reach full operating temperature, and a brief warm up is only recommended to ensure that oil pressure has stabilized and moving components of your engine have had a chance to warm up; different materials expand at different rates, so you never want to put a load on a dead cold engine. In temperatures below freezing, you may consider using a block heater per Ford’s instructions.
Avoid Excessive Exhaust Gas Temperatures (EGTs)
High EGTs (typically above 1,300 °F or 704 °C) can be an indicator of dangerous conditions that can lead to catastrophic engine failure.
Damage from excessive EGTs usually start with the turbocharger. Under sustained excessive EGT, the square corners at the outer ends of the vanes, where the material is thinnest on the turbine wheel, can become incandescent and then melt, resulting in a rounding off of the square corners. If you or your mechanic finds this indication before anything more serious happens, consider yourself very lucky, because shortly after the tips melt, the turbine wheel goes out of balance and wipes out the turbocharger bearings, which may or may not result in shaft failure and destruction of the turbine and compressor wheels.
Excessive EGT Potential Damage:
- Turbocharger failure
- Piston deformation, melting, burning, holes, cracking
This damage is cumulative, so if you slightly burn a piston top, the engine may continue to run without problems, but the next time you run excessive EGT more damage may be done, and so on, until failure occurs. Piston failure can be very expensive. At a minimum, an engine overhaul will be required. Excessive EGT can also cause exhaust manifold and cylinder head cracking. Exhaust valves can fail from high EGT as well. Among the first engine parts to suffer damage will be those made of aluminum because aluminum has a lower softening and melting temperature than steel or cast iron.
EGT is an indication of how hot the combustion process is in the cylinders, and the amount of “afterburning” that is occurring in the exhaust manifold. EGT is also directly related to the air/fuel ratio. The richer the air/fuel ratio in a diesel, the higher the EGT will be. Two things can create a rich mixture under heavy loads or at full throttle: the first is too much fuel, and the second is not enough air. That seems simple enough, but it’s the second part, not enough air, that could get an unmodified Power Stroke engine into trouble. Anything that restricts intake airflow, or intake air density, limits the air mass that gets to the cylinders.
Restrictive Exhaust Systems & EGT
A restrictive exhaust system can also reduce the airflow through the engine, resulting in a rich condition. The above conditions can result in excessive EGTs, if the vehicle is working hard, such as when pulling a heavy load, running at sustained high speed, climbing a long grade, or running performance tuner chips.
A pyrometer is a good investment that will enable you to easily monitor the EGTs and avoid damaging your engine. If you see EGTs climbing over 1300º F., the fastest way to reduce the amount of fuel going to the engine is to back off the accelerator pedal. Another possible solution is to down shift, if your speed permits it.
Cool Down Before Shutdown
Always allow a Power Stroke engine to cool down by idling until the Exhaust Gas Temperature (EGT) is cool enough, typically around 300 degrees Fahrenheit, before shutting off the engine. This gives the turbocharger an opportunity to cool enough to preventing oil from cooking once the engine is shutdown and oil stops circulating through the turbocharger. The acceptable ideal temperature will be different for different types of oil, the synthetics having higher flash points, typically.
The purpose of the cool-down is for the shaft of the turbo which is supported by two very-low-friction bearings to receive a continuously replenished stream of oil as this shaft may rotate at upwards of tens of thousands of revolutions per minute. The shaft easily achieves temperatures of hundreds of degrees but this is managed by the continuous replenishment of oil circulated by the running engine. If the supply of oil is cut off at engine shut down AND the shaft remains at or near the flash point of the oil then the oil will coke (solidify). If the oil cokes on the shaft the chance of the shaft seizing is greatly increased. A seized turbo would result in very poor performance and potential engine damage.
The flash point of the oil may be measured during an oil analysis. The standard used by Blackstone Laboratories is >410F, so a shut down below this usually assures safe conditions for the turbo shaft. Synthetic oils generally have a higher flash point than mineral oils. The temperature selected is a bit subjective because it is an indirect measure; the temperature of the turbo shaft is not actually measured.
The use of a pyrometer for an indirect assessment of the turbo shaft temperature is a very good way to protect against coking. A guesstimate of a couple of minutes after you “go easy on her for the last few miles” might be sufficient but without an accurate measure, that is gambling. There are some devices that allow you to physically shut down but keep the engine running (without the key in the ignition) until a pre-determined setting is achieved.
The timing of shut down – as well as the temperature of the shut down (of a measured EGT) – is dependent upon the type, grade, and quality of the oil, the location of the pyrometer, the driving conditions prior to shut down, the ambient temperature, etc. Ultimately, the use of synthetic oil that is regularly changed and sampled for quality assurance (determination of the actual flash point), and a pre-turbo pyrometer indicating under 400 degrees results in a turbo shaft temperature under the flash point of that synthetic oil.