How to replace the muffler on a 2000 Dodge Grand Caravan

                                  Replacing the Muffler on a 2000 Dodge Caravan 3.0L engine
 
     The savings aren't huge replacing exhaust parts, but for me it's still worth it to have control of this repair. I find that exhaust shops tend to bundle other (still good) pipes with the muffler replacement. When buying a replacement, it is worth inquiring at the auto parts store if their replacement muffler will fit on the existing OEM hanger. If not, check the cost of the hanger. They can be rather expensive. This procedure covers a way to fabricate a hanger out of basic materials. The job is much easier (but also more expensive) with an OEM muffler.
    I'm a die-hard home mechanic, not a professional. While I strive for accuracy and attention to detail in these procedures, I cannot guarantee that every step and description is flawless.  If in doubt, consult a auto repair manual or the services of a professional mechanic. Above all take your time and be safe.
 
                                                            The Repair Basics                                            

• Safety: Safety glasses, gloves, ear plugs, dust mask and a tarp to screen the fuel system off from sparks. 
•  Tools: A pair of car ramps for the back wheels at least. Two pair are even better. A angle grinder and possibly a rotary cutting tool, such as a Dremel, with a reinforced cutting wheel. A hammer and large screwdriver or chisel,  and a hacksaw may be needed. If fabricating a hanger, an electric drill, C-clamps, a round file, drill bits and a round sanding stone or similar tools may be needed. 
•  Parts and materials: Muffler, 2 and 2 ¼” exhaust clamps, a tube of exhaust sealant. If fabricating your own hanger: 14 gauge (1/16”), x 1 3/8” x 5’ flat steel with 3/8” holes drilled every ¾”, two 2 inxch long 7/16” x 14 bolts, two 7/16” x 14 nylock nuts, matching washers. Two 3/8” x ½” long bolts with nuts, washers and lockwashers. 
•  Cost of materials: $68.49 for a direct fit American-made muffler from NAPA. Muffler clamps $4.98. Sealant: used tube on hand (est $3-5). Hanger for this aftermarket muffler $34. If fabricating a hanger: Strap steel $6.60, hardware $2.71. 
•  Shop labor cost for the job: $50-75. 
•  Home mechanic estimated time: 2-3 hours   

                                                   Removal of the old muffler

  Put a barrier between the gas tank and the muffler to keep sparks away from the fuel tank and lines. I pinned up a tarp.
1) Cut off the clamp on the upstream side of the muffler. I used a 4 1/2" angle grinder to cut through the width of the clamp. Just cut the sixteenth of an inch or so of the clamp. Then I used a hammer and large flat screwdriver to pry the clamp off.

Note the tarp for a barrier for stray sparks from the cuttting

2) The muffler, pipe downstream of it and the resonator and tailpipe are one piece on this vehicle. Your van may be different. I had to cut the downstream pipe off just past the weld to the muffler, as it will be re-used with the new muffler. Using the angle grinder I was able to cut off the lower 60% of the pipe. I removed the rest with a reciprocating saw (name brand “Sawzall”). A hacksaw can also be used.

3) Unclamp the muffler hanger. I used a 1/2" wrench on the bolt. It snapped off. At this point I expected to re-use the hanger, so I cut the nut off that was welded to the lower steel strap of the hanger. I used a Dremel
rotary tool with a reinforced cut-off wheel. Then I removed it with a hammer and chisel.

4) Remove the muffler. The only thing left to do is to separate the muffler from the upstream exhaust pipe. On this van there was already a 3 inch slot in the muffler pipe. I used a hammer and chisel to separate that gap further with a prying motion. Then I cut the remainder of the overlap with a rotary tool, taking care not to cut into the upstream exhaust pipe below. Then I used the chisel again to separate and bend the muffler pipe portion upward till it was freed from the other pipe. Now the muffler could be pulled through.

6) The original factory clamp did not fit my aftermarket muffler.  It is a very rigid clamp, the lower portion particularly. The replacement muffler is much more pancaked. This is something worth asking the parts store before purchasing the muffler. The hanger is $34.95. The muffler cost $68.

7) I decided to fabricate a hanger. This section may be useful if you want to tackle that. I bought some 14 gauge steel flat stock, 1 3/8” wide with 3/8” holes every 3/4 inch. I cut two pieces 24 inches long and formed them around the muffler.

 Mark them at the muffler side seam and bend in a vice so the ends stick out at right angles from the edge of the muffler. Now put a bolt, nut and lock washer through the holes nearest the muffler.

   Now we need to determine where the ends of the straps need to be bent to mount to the outside of the existing rubber hangers on the van. So put the muffler in place, seating the pipes on both ends and mark where the straps need to be bent. Bent the straps and go under and mount the muffler again to mark where the hole for the mounting bolt will be drilled. Drill the hole and do the final mount on the muffler. I wanted the use both thicknesses of strap so the hanger would be strong, so I clamped the two pieces and used a drill stone and round file to make the holes align. Then I drilled through both straps to the final 3/8” diameter for the bolt.

                                                                        Installation
1) Use a file or wire brush and lacquer thinner to clean up the contact surfaces on the existing pipes where they will fit inside the new muffler.
2) Apply a generous layer (1/4") of muffler and pipe sealant to the mating surfaces of the old pipes.
3) Fit the new muffler over the upsteam pipe first and then seat the tail piece pipe inside the downstream end.

4) Remount the hanger. If able to use the existing hanger, put a new nut and bolt on the clamping side and torque it down. If using a fabricated hanger, run a 2 inch bolt and washer through the rubber hanger from the muffler side and thread on the locking (“Nylock”) nut. Torque it till the rubber begins to be squeezed. Repeat on inboard side.
5) Mount the 2 ¼” clamp to the upstream pipe joint.
6) Mount the 2 inch clamp to the downstream pipe joint.
7) Allow the sealant to dry for a while (optional).
8) Run it and test for leaks and enjoy the peace and quiet.


Here are some videos of the process:                Part 1

Part2

Part 3