99 v6 3.0 flex new fuel filter

[jim22]

I've got probably 6-8 hours into it, but tonight I finally installed a new fuel filter on my truck. Here's how it went...

First step: Remove the connector from the fuel cut-off switch below the glove box on the passenger side. Loosen the fuel tank cap. Crank the engine for 15 seconds. The second time I did this I started the engine and disconnected the switch while the engine was running. This depressurizes the fuel system.

The fuel filter is located mounted to the driver side frame rail. The outlet is a 5/16" coupling with a white clip. The clip had a small tab which prevented it being removed, so that had to be removed (just bend it over and it breaks off). Then spread the legs a little and the clip pulls out the top with little effort. At that point the coupling was free to be pulled off, again with very little effort.

The inlet is a 3/8" quick disconnect coupler. This coupler has a metal shell with various diameters, the largest being nearest the fuel filter. It had a large metal retainer on it which unhooks on the top rear and then rotates down and slides forward to free it from the connection. Then the fun began!

I did some research and knew I needed a disconnect tool for this coupler. The first tool I tried was an OEM tool purchased at Autozone for about $11. This is a metal tool, kind of like a pair of scissors, with a 3/8" end and a 5/16" end. The idea is to close the tool on the filter inlet tube and slide the tool under the coupler shell, spreading 3 tabs inside the coupler so that they clear a flange on the filter inlet tube. This tool was manufactured so poorly that it would not close completely around the 5/16" tube and would not slide under the coupler. Back to the parts store!

The second tool I tried was a plastic collar-type purchased as a set from Napa (No. 3530) for about $12. I spread the open side of the collar onto the filter tube and slid it under the coupler shell. It seemed not to release the coupler. Either it really did release and I still couldn't get the coupler off or it did not lift the coupler tabs high enough to clear the flange. Back to the parts store again!

The third tool I tried was another metal scissors-type tool of the same design as the first. This time I spent $22 at NAPA (No. 3321) and got their version of it, which was labeled "K-D" and appeared to be much better made. Before I even tried this tool I cleaned up the working end welds with a file and some fine sand paper until I was satisfied that it would close completely and slide easily on the inlet tube.

I clamped the tool onto the inlet tube and this one slid under the coupler shell. I thought I felt the coupler click free when I first did this, but I'm not completely sure. The coupler did not slide off with moderate effort. Eventually I discovered that it really was released and that I could twist it back and forth while pulling the connector away from the filter. It took considerable force to remove the coupler.

I thought removal would be the tough part until I got it apart. Then I discovered why I had so much trouble. The inside of the coupler, just behind the retainer clips, was rusted, reducing the inner diameter of the coupler. Also, there are two o-rings inside the coupler which appeared to be out of place. The new filter would not go on.

To solve this, I ended up pulling out the o-rings. The inner o-ring was black, and the outer o-ring was blue. They didn't look like they were exactly the same size. They are separated by a flat plastic washer. After I pulled out the o-rings (the plastic washer didn't want to come out), I used a small half-round file to open up the rusted inner diameter until the new filter would slip in. Then I wrestled the o-rings back into place, which was not really easy. When I was done, the new filter, lubed with engine oil, slipped right on and the clips snapped in place over the flange.

The front connector went on without any hassle. I reinstalled it with the old clip for now until I'm sure I like the installation and there are no leaks. Then I'll swap in the new clip that came with the fuel filter.

The filter itself was a CarQuest filter. The body diameter was the same, and the inlet and outlet tubes were mostly the same, but the geometry of the filter was a little different. Once snapped into the retainer clip on the frame the inlet hose is stretched a little farther than the original part. I think it's ok, but I would have preferred it to have been a better fit. I'll think about it for a few days, maybe I'll look for a Motorcraft filter.

Hope this is useful for the next guy.

Jim

[greyghost]

thanks for the write up, it can be fustrating if you don't get the spring clips out the first time but it sounds like you made the best of it.