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Chevy Duramax Diesel Fuel Filter - Do-I...
Chevy Duramax Diesel Fuel Filter - Do-It-Yourself Diesel
Filthy Fuel And Filtration Frustration
, Photography by Charles Evenson, Gary Blount
March 01, 2006
1. The Duramax fuel filter is located on the passenger side of the engine compartment, back toward the firewall, right next to the battery. If you have big hands, you can pretty much forget about getting to the fuel filter. Removing the plastic fenderwell exposes the filter, providing easy access through the fenderwell opening. That's probably why we were told it would cost $150 to have GM replace a $40 fuel filter. About 14 plastic snap fasteners hold the plastic fender in place, and it took all of about 2 minutes to pull them off. It took longer to fish out the plastic inner fender, due to our lift kit that holds twin piggyback Fox Shox dampers in the dual shock mount.
1. The Duramax fuel filter is located on the passenger side of the engine compartment, bac
2. This is the petcock from our GM water sensor and bleeder. The fuel filter should be replaced every 15,000 miles. In between replacing the filter, you can bleed off the water in the separator built into the filter. We broke open the petcock to see how much water was trapped in the filter. The bad news is that nothing came out, even when we completely removed the petcock.
2. This is the petcock from our GM water sensor and bleeder. The fuel filter should be rep
3. Looking through the fenderwell, you can see the bottom of the fuel filter. As you can see, the water sensor screws into an opening in the bottom of the filter. The water separator cylinder is in the middle of the filter. The plastic sensor bulkhead screws into the bottom of the filter, forming the water trap.
3. Looking through the fenderwell, you can see the bottom of the fuel filter. As you can s
4. When the filter you're trying to remove only allows for 10 degrees of a turn, the strap wrench can be a great help. Like most filter wrenches, you can fix it to the filter at any position, face up or down. The cool thing about the strap wrench is it's flexible, and you can use an extension on it. This tool is truly a must for anyone wanting to replace a Duramax fuel filter or a Ford Expedition oil filter.
4. When the filter you're trying to remove only allows for 10 degrees of a turn, the strap
5. To get the wrench around the filter and to remove it from the filter mount, you must unplug the water separator sensor. Follow the wires to the connector plug pinched under a metal tab on the cylinder head. Don't be afraid to bend the tab back slightly to pull the plastic connector out.
5. To get the wrench around the filter and to remove it from the filter mount, you must un
6. Make sure you don't place the wrench too close to the base of the filter; it may collapse under pressure and damage the plastic bulkhead threaded into the bottom of the filter.
6. Make sure you don't place the wrench too close to the base of the filter; it may collap
7. Upon breaking the filter free, water came streaming out, indicating the filter was full of water. This was obviously why our diesel was running like crap, and why we decided to investigate the fuel filter.
7. Upon breaking the filter free, water came streaming out, indicating the filter was full
8. The contents of the filter were 50 percent fuel, 40 percent water, and 10 percent God knows what. Yep, we had definitely found our wide-open throttle problem.
8. The contents of the filter were 50 percent fuel, 40 percent water, and 10 percent God k
9. Removing the sensor bulkhead from the filter shows the filter was performing its duties. All the impurities definitely sealed to bottom of the trap.
9. Removing the sensor bulkhead from the filter shows the filter was performing its duties
10. A lot of water came out of the trap in the old fuel filter, and we wondered if the sensor on our filter had gone bad. Water is heavier than diesel fuel, and the float on the sensor is weighted to float on water. So, as the trap fills with water, the float will rise with the water till it connects an electrical circuit. The circuit sends a signal to the ECM, and in turn, the ECM displays a code on the dash. Our float was loaded with rust, which prevented it from moving, never triggering a water trap problem.
10. A lot of water came out of the trap in the old fuel filter, and we wondered if the sen
11. The new fuel filter comes with all new O-ring seals for the sensor bulkhead and filter's sealing surface. Lubricating the O-rings with petroleum oil (form of light grease) will help hold them in place, while you fasten the filter, and will condition the rubber seals, protecting them from the conditions the engine compartment is subjected to.
11. The new fuel filter comes with all new O-ring seals for the sensor bulkhead and filter
12. This sensor bulkhead is plastic, so don't over-tighten it, or you will strip out the plastic threads. The wires coming out of the plug run over the exhaust manifolds. Make sure these wires are not brittle. If they are, replace the sensor altogether.
12. This sensor bulkhead is plastic, so don't over-tighten it, or you will strip out the p
13. Don't be afraid to put a little pressure on the filter seal. Tighten it well with your hands to ensure there are no fuel leaks.
13. Don't be afraid to put a little pressure on the filter seal. Tighten it well with your
14. The last thing you want to do is run your high-pressure pump dry. GM Duramax engines use a common-rail fuel-injection system, which uses the diesel to lubricate and cool the Bosch high-pressure pump that supplies as much as 23,000 psi of fuel pressure. Hurt that pump, and you'll hurt your pocketbook. The fuel filter mount also has a manual fuel pump designed in it. This primes the filter, so you don't run the high-pressure pump dry. The two fuel lines going in and coming out of the filter are marked with arrows indicating the direction of flow. The line the goes from the pump to the high-pressure pump has a relief valve (a black plastic fastener) on it. Opening the relief valve will allow you to bleed the fuel system of air at the filter. With the relief valve open (about one full turn), pump the manual valve till fuel squirts out of the relief valve. Close the relief valve and continue pumping till you can't push the primer plunger down anymore. While you have someone start the truck, continue pumping till the truck starts. Should the truck stall, continue primer sequence till the truck idles properly.
14. The last thing you want to do is run your high-pressure pump dry. GM Duramax engines u
One way to combat water and impurities is the use of fuel additives, like this one from Rolling Big Power (RBP). Even though these additives don't dissipate water like marketing has forced them to claim, they definitely take care of water with an oil-based additive that attaches itself to the water molecules. This additive also carries a 4 to 5 percent increased cetane (what octane is to gas) rating, allowing the diesel to burn increased water percentages without adverse effects. In fact, the additives help lubricate and clean the injectors, and in some cases they'll supply a smidge of performance to boot. Additional filtration is good as well. Diesel Performance Products produces the FASS Fuel System, which not only cleans the diesel of moisture and particulates, but it also eliminates foaming, which increases power by delivering air-free fuel. The system can be purchased in high volume as well as high pressure, which eliminates high-pressure pump starvation with high-horsepower engines.
One way to combat water and impurities is the use of fuel additives, like this one from Ro
Diesel Performance Products
Rolling Big Power (RBP)
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