Changing the Fuel Filter on a Late Model C4
Changing the fuel filter on a 1993 C4
Tools required: 16 mm and
13/16 inch open/box end wrenches, 13/16� socket, 10 mm open end wrench, 10
mm socket, safety goggles, latex gloves to keep the gas off your hands in
case you get to hold your lady that night, small to medium size hands, a
fire extinguisher close at hand, and finally, two buckets of patience. If
you tend to have a lot of table muscle (from eating too much) you will
never fit under the car with it on jack stands.
The fuel filter is
located along the frame rail on the right side of the car. This job could
best be accomplished with the car on a lift, but can be done with the car
on jack stands. I used the jack stands. The car should have less than �
tank of gas.
Procedure: Loosen the fuel filler cap to relieve the
pressure from the tank. From this point on I wore safety goggles, not
safety glasses. Remove the right fuel rail cover. Place a rag under the
shrader valve where you would normally attach a fuel pressure gauge.
Remove the shrader valve dust cover and press the valve stem to relieve
the pressure on the fuel system. My car had not been started for two
weeks and the gas cap was left loose for several hours before I started.
About 4 tablespoons of gas came out of the shrader valve. Replace the
dust cap on the valve and the fuel rail cover. Tighten the fuel filler
I used a quartz work light under the car to see, but made sure
to keep it a distance from any gas or gas vapors. I opened the garage
door and turned on the ceiling fan. Remove the two screws that hold the
two fuel lines to the under side of the car using a 10 mm socket. These
are located along the right rocker panel and are the two screws located
closest to the fuel filter. This is necessary so that you can remove the
stainless steel tubing on the input side of the filter.
the strap that holds the fuel filter to the car frame using the 10 mm
open-end wrench. This screw was behind the return fuel line. I had to
wedge a � socket extension between the frame and the return line in order
to have enough room (enough room is a relative term when working on a
Corvette) to remove the screw. Even then it was very tight quarters.
Remove the input fuel line from the filter by holding the filter with the
13/16-inch wrench and turning the nut on the fuel line with the 16 mm
wrench. On my car about 1 cup of gas ran out when I loosened this
connection. I caught it in a coffee can and a rag. Once it stopped
draining, I dumped the gas out of the can and placed the gas soaked rag
outside of the garage.
The top fuel line on the filter is another
story. I have heard that some remove the fuel line where it connects to
the fuel rail and pull the filter up and out of the engine compartment to
change the filter. I couldn�t figure out how to break the connection at
the fuel rail so I removed the line from the top of the filter. The
catalytic converter is in the way of the upper fuel filter connection. I
had to place the 16 mm open-end around one side of the cat closest to the
fuel filter, and then use my index finger of my right hand and hold the
wrench this way. My right hand was around the other side of the cat.
Since I was replacing the filter I didn�t care if I ruined the old filter.
I used a 13/16 socket on the bottom of the filter to loosen the filter
while holding the top fuel line with the 16 mm wrench. I ended up bending
the bottom fitting on the filter, but got the filter off of the top fuel
Inspect the o-rings on the two gas lines before installing
the new filter. New O-rings are not included with the new filter. Place
the filter on the top fuel line and reverse the procedure to tighten the
fuel lines to the new filter. Use care when turning the new filter with
the socket wrench so that you don�t bend the filter. One of the hardest
jobs was replacing the retaining strap around the new filter. I had to
wedge the return line out of the way and it still took me 15 minutes to
get the holding screw started into the frame of the car.
everything has been re-assembled and tightened, start the car and let it
run for 1-2 minutes. Shut off the engine and check for any fuel leaks.
This is very important as a leak could drop or spray fuel on the catalytic
converter and you would have a really hot set of wheels, no pun intended.
I repeated this staring procedure several times over the next several
hours to insure I had no leaks.
Not counting the time it took me
to get the car on jack stands, this job took me about 90 minutes. I�m not
sure I could do it again in less then 60 minutes.
Now if I could
only find a good price on some new muffler bearings I replace them while
the car was still on the jack stands.