Changing Fuel Filter

chadhargis · **Posted:** Sat Apr 21, 2007 3:50 pm

I bought a new fuel filter, but my service manual hasn't arrived yet.

Being that this is my first diesel, do you need to de-pressurize the fuel system to change the filter. I know on gassers you have to releave the fuel pressue.

If so, how do you do it on the CRD? Do I simply pop open the bleed valve on the filter/seperator unit?

Other than the questions above, it looks similar to changing an oil filter, only you have to move the sensor off the old filter to the new one.

RFCRD · **Posted:** Sat Apr 21, 2007 4:33 pm

chadhargis wrote:

I bought a new fuel filter, but my service manual hasn't arrived yet.

Being that this is my first diesel, do you need to de-pressurize the fuel system to change the filter. I know on gassers you have to releave the fuel pressue.

If so, how do you do it on the CRD? Do I simply pop open the bleed valve on the filter/seperator unit?

Other than the questions above, it looks similar to changing an oil filter, only you have to move the sensor off the old filter to the new one.

Start with this, your fuel system is not pressurized. It's a vaccuum/suction system so you won't find any pressure unless you put it there with the primer pump. Before cahnging the filter, would check the old head assembly for leaks by using the primer pump to pressurize the system. If it leaks, your dealer will replace the whole assembly under warranty saving you the cost of the new filter.

To change the filter, first remove the electrical plug to the WIF sensor on the bottom of the filter. Then, unscrew the WIF to drain the filter (save the WIF sensor). Using a strap/band wrench, unscrew the old filter being careful to not damage the fittings on head assembly. You may have to remove a fuel line to get your strap in place. Pay close attention to the head assembly for any rotational movement that would indicate a bad head.

To re-assemble: There is some debate as weither or not to pre-fill the new filter with fuel. I personally would but have told this is not necessary with the primer pump. If you do pre-fill the filter, plug the center hole and only fill from around the edges. Make sure the WIF sensor is in place before filling. An old coffee can with some paper towels packed around the sides makes a good stand for the filter while filling. Install the new filter, prime & bleed as stated in the manual.

retmil46 · **Posted:** Sat Apr 21, 2007 8:22 pm

RFCRD wrote:

Start with this, your fuel system is not pressurized. It's a vaccuum/suction system so you won't find any pressure unless you put it there with the primer pump. Before cahnging the filter, would check the old head assembly for leaks by using the primer pump to pressurize the system. If it leaks, your dealer will replace the whole assembly under warranty saving you the cost of the new filter.

To change the filter, first remove the electrical plug to the WIF sensor on the bottom of the filter. Then, unscrew the WIF to drain the filter (save the WIF sensor). Using a strap/band wrench, unscrew the old filter being careful to not damage the fittings on head assembly. You may have to remove a fuel line to get your strap in place. Pay close attention to the head assembly for any rotational movement that would indicate a bad head.

To re-assemble: There is some debate as weither or not to pre-fill the new filter with fuel. I personally would but have told this is not necessary with the primer pump. If you do pre-fill the filter, plug the center hole and only fill from around the edges. Make sure the WIF sensor is in place before filling. An old coffee can with some paper towels packed around the sides makes a good stand for the filter while filling. Install the new filter, prime & bleed as stated in the manual.

Would add a couple thing based on my experience -

When you remove the WIF sensor in the bottom to drain, also open the bleed screw on the filter head. Looks like a standard brake bleed screw, only need to open it a half turn or so. Makes draining the old filter a whole lot faster.

Replace the old rubber gasket on your WIF sensor with the one from the blank white plug that's screwed into the bottom of your new filter.

You can disconnect the two wiring harnesses attached to the filter head and move them out of the way for additional clearance while doing the changeout. If need be, don't be afraid to disconnect both fuel lines from the filter head - just rubber hoses with clamps - but don't forget which one goes where!

an alternate method many people have found easier is simply to remove all 3 electrical harnesses and both fuel lines, then loosen the two nuts on the mounting bracket and remove the entire assembly from the vehicle, drain and change out the filter on a workbench, then reinstall in the vehicle, reconnect all harnesses and fuel lines, then reprime the filter.

Since you don't have a manual, here's how I reprime mine - leave the bleed screw open about 1/2 turn and operate the priming pump until you start getting fuel spitting out along with the air.

Then snug down the bleed screw, operate the priming pump until you feel a significant increase in resistance while pushing on the plunger. Crack open the bleed screw and vent off the filter head. Repeat this until you get a solid stream of fuel coming out of the bleed screw.

Then tighten down the bleed screw for keeps (don't monkey torque it - bleed screw and filter head are made of relatively soft metals - just whatever's necessary to get it to seal). Operate the priming pump again until you feel a significant buildup of pressure. Start the vehicle and let it run for a couple of minutes at least to make sure any remaining air is purged out of the line downstream of the filter.

chadhargis · **Posted:** Sat Apr 21, 2007 11:29 pm

Good info. The filter was REALLY easy to change.

I removed the electrical connections, unscrewed the filter, removed the WIF sensor and drained the old filter. Put the WIF in the new filter and followed the instructions in the owners manual to purge the air. I didn't open the bleeder screw, but the engine is running fine. Is there any reason to fix it if it ain't broke? The bleeder has to be there for a reason.

RFCRD · **Posted:** Sun Apr 22, 2007 9:05 am

chadhargis wrote:

Is there any reason to fix it if it ain't broke?

A very good question to ask with a diesel. With a fuel filter the answer is yes. Personal opinion but DCX has the filter change interval way too long for good reliability given the quality of diesel fuel in the US. Would change it at least once a year, preferably in the Fall just before the weather freezes.

Cowpie1 · **Posted:** Sun Apr 22, 2007 10:15 am

RFCRD wrote:

chadhargis wrote:

Is there any reason to fix it if it ain't broke?

A very good question to ask with a diesel. With a fuel filter the answer is yes. Personal opinion but DCX has the filter change interval way too long for good reliability given the quality of diesel fuel in the US. Would change it at least once a year, preferably in the Fall just before the weather freezes.

Very sound advice! If a problem is going to come up, it will do so when the weather gets colder. Standard policy for me with my Semi or my CRD is to keep an extra filter on hand during the winter as well since dealers may not keep them in stock due to low demand. This and making sure you get good, clean fuel and you will keep Murphy's law from kicking in.

chadhargis · **Posted:** Sun Apr 22, 2007 8:07 pm

So what about the bleeder? Do I need to open it to purge any remaining air, or just leave it along. The CRD runs fine.

Just towed by bike to the track today and had to work to keep it under 80mph. It just wants to do 80.

RFCRD · **Posted:** Sun Apr 22, 2007 9:19 pm

chadhargis wrote:

So what about the bleeder? Do I need to open it to purge any remaining air, or just leave it along. The CRD runs fine.

Just towed by bike to the track today and had to work to keep it under 80mph. It just wants to do 80.

If it's running fine I wouldn't mess with it. You would know if you have air in the lines as you will see hesitation and/or bucking-stumbling after hard accelleration. Also a word of caution about the bleeder, some have stripped the threads trying to bleed the system. Handle with care.

Changing Fuel Filter

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