Fix It

The Toyota Previa muffler is not a hard one to replace. The hardest part might be locating the correct muffler for the year and model Previa you have. In other words, whether its a DX model Previa or an LE model Previa. Choosing the brand of muffler may be another challenge and then finding the availability of one. Toyota will have one for about $350 plus shipping. However you can find one in the aftermarket world for less than half of that with the same kind of warranty and shipped to you just as quickly. Bosal is a fine import aftermarket exhaust system manufacturer and you can purchase or order them through many local parts stores or find them online. Just make sure you have all the information about our Previa before you do.

Instructions

1

Lift the Previa all the way up on a car lift.

2

Locate the flange connection of the muffler inlet pipe just forward of the rear axle.

3

Put on cutting glasses and gloves and light the torch. Cut the two bolts on the muffler side of the flange connection until they are melted or cut below the flange itself. Turn off the torch.

4

Strike the muffler side of the flange with a hammer to separate the two flanges. If you have to, use the punch and hammer to knock out the cut bolts through the other flange. Once the separation of the flanges are complete, switch over to the safety glasses so you can see better.

5

Remove the muffler hangers (front and rear) from the rubber hangers on the frame of the Previa. Discard the old muffler.

6

Clean any remnants of the old gasket off of the pipe flange where you cut the muffler from using the gasket scraper.

7

Install the new muffler in the same manner you removed the old one. Place the rubber hangers on the frame onto the muffler hangers to hold it in place for you. The rear axle will hold the inlet pipe in place.

8

Insert the new gasket and connect the new muffler flange to the pipe flange. Connect with the 10 millimeter hardware placing the flat washer on the bolt head side of the flange and the lock washer and nut on the other side.

9

Secure the bolt head in place with the box wrench and tighten the nut with the gun and socket. Tighten one side snug. Then bring in the other side. Do not tighten one side securely first and then the other, or you may kink the gasket.

10

Lower the Previa and start it up to check for any leaks at the flange connection.

Vehicles have a wide array of exhaust systems, and muffler sizes also vary. Larger diameter exhaust piping, including the muffler, allows more exhaust to flow out from the engine. However, large exhaust piping will not always increase vehicle performance.

Function

An exhaust system releases gases exhausted out of the engine. Carbon monoxide is a byproduct of exhaust and the reason exhaust systems use a catalytic converter, which decreases the amount of carbon monoxide released into the atmosphere. An exhaust system includes multiple components including headers, piping, catalytic converter, muffler and tail pipe.

Muffler & Piping Diameter

Muffler and piping size determines the flow of exhaust. Overly small piping will restrict exhaust flow and the velocity at which it is expelled. Overly large piping and mufflers will decrease exhaust velocity even though there will be an ample flow. Ideally, muffler and piping diameter design balances the flow and velocity, creating optimal power.

Back Pressure & Engine Performance

Exhaust back pressure directly affects engine top-end performance. A high amount of back pressure decreases exhaust flow by backing up exhaust in the engines air/fuel mixture, reducing available power. Back pressure builds during heavy acceleration. Muffler and exhaust piping size determine the back pressure an engine must fight against.

The Chevy Impala has enjoyed three runs with the GM corporation from 1958 to 1985, from 1994 to 1996 and from 2000 to the present. This full size car may have a single pipe system or a double pipe system, which is important to know when replacing the muffler. If you find holes in your muffler or it starts making loud noises, then its time to replace it.

Instructions

1

Spread out an old blanket or a large piece of cardboard on the ground to lay on as you replace the muffler. For an easier time repairing, you might consider jacking the car up and placing it on jack stands instead.

2

Purchase a new muffler. It must have a 2.25-inch center inlet/outlet, be 4 inches thick by 9.75 inches wide, and 13 inches long. Make sure it is the right one according to the model year of your vehicle.

3

Look over the old muffler. Spray the fasteners generously with a penetrating lubricant before you loosen them. The penetrating lubricant will help you to remove the screws and bolts with ease.

4

Loosen the bolts at the bottom of the muffler strap. Its okay to let the muffler hang. Using a hacksaw, saw the stock muffler completely off of the pipe, leaving 1 inch to 1 1/2 inches of straight pipe at the muffler inlet, if you have a single pipe system. Alternately, if you have a dual pipe system, take of the U-bolt clamp found on the front of the muffler and remove the muffler from the exhaust pipe.

5

Take of the tailpipe clamps and then remove the tailpipe. After taking off the muffler and tailpipe, inspect all the hangers and replace any that are damaged.

6

Put the muffler into place under the vehicle. Make sure the muffler inlet slips over the exhaust pipe with ease. Put sealer on the connecting surfaces and then straighten the muffler over the pipe. Tighten the muffler clamp on the muffler inlet using a flathead screwdriver and then tighten all clamps starting at the front of the muffler and working youre way back.

7

Lower the car, start the vehicle and carefully inspect the muffler for leaks and loud sounds. If there are any, youll need to tighten the bolts more. However, the clamps should be loose enough to allow the muffler to move a little with the movement of the car.

The muffler on the 1998 Dodge 3500 Diesel is the main component that prevents the diesel engine running too loud. The exhaust pipe that is attached to the exhaust manifold on the front of the engine travels under the truck and into the muffler. As the sound of the engine travels through the muffler, the baffles inside of the muffler cause the sound to exit in a quieter manner. Over time, the excessive heat that travels through the muffler, will cause the inside of the muffler to rust and not perform properly.

Instructions

1

Park your 1998 Dodge 3500 Diesel on a flat surface and engage the parking brake. Wait one to two hours for the muffler and the exhaust system to cool down.

2

Slide under the rear of the truck and locate the front of the muffler. The exhaust pipe that travels from the engine is mounted to the front muffler port by a metal clamp with two mounting bolts.

3

Saturate the two mounting bolts completely with the rust inhibitor spray or the penetrating oil. Position a socket and a breaker bar onto one of the mounting bolts. Slowly turn the bolt counterclockwise to see how tight the bolt is fastened. If the bolt is still tight, spray more of the rust inhibitor or the penetrating oil on the mounting bolts and repeat the process with the breaker bar and socket until the bolt is loose. Follow the same step with the other mounting bolt. Once the bolts are loose, use a ratchet to finish unscrewing the bolts.

4

Finish loosening and removing the two mounting bolts from the clamp with a ratchet and a socket. Pull the mounting bolts out of the clamp and knock the clamp off of the muffler port with a hammer.

5

Slide the end of a flathead screwdriver into the end of the muffler. Pry the end of the muffler port upward off the exhaust pipe. Make sure the entire front muffler port is pried up off of the exhaust pipe. Try and pull the muffler loose from the exhaust pipe. If the muffler is still stuck, use the hammer to tap the front of the muffler loose from the exhaust pipe.

6

Pull the muffler off the rubber hanger that holds the muffler in place. Slide the muffler out from under the truck. Position the new muffler under the truck and into the rubber hanger.

7

Slide the front port of the muffler over the exhaust pipe. Reconnect the clamp over the exhaust clamp and the muffler with the two mounting bolts. Tighten the bolts down tight with the ratchet and socket. Finish torquing the mounting bolts with the breaker bar and a socket.

One of the most important functions of a cars exhaust system is to protect the occupants of the vehicle from hazardous fumes. If the exhaust system leaks, carbon monoxide and other waste gases can collect in the cabin and harm or kill the passengers. Because of the abuse and exposure suffered by the exhaust system, faulty or leaking parts are usually replaced. If the exhaust system is sound enough, it can be repaired.

Braze Welding

Braze welding is a way to join two metals with different melting temperatures. The filler metal has a lower melting point than the base metal. Small holes in a muffler may be patched by braze welding filler material into the holes. Larger holes in a muffler may be repaired by braze welding patches of steel over the holes.

Brazing

Brazing is similar to braze welding in that the filler material has a lower melting temperature than the base metal. The difference between brazing and braze welding is that in brazing the filler metal is drawn into the joint by capillary action. In plumbing, this process is called "sweating" a joint. Exhaust pipes can be repaired at the joints by brazing.

Why Does the Shop Want to Replace Instead of Repair?

Repairs to any metal can only be done where the metal is in good shape. The exhaust system of a car is subjected to abuse from both the inside and the outside of the system. The temperatures of exhaust gases are high enough to weaken any metal. Cars driven in areas that use salt to clear snow from the road can suffer corrosion very quickly. If an exhaust system is more than two or three years old, it probably is not a candidate for repair.

Benefits of Braze Welding or Brazing

Joining metals with either a brazed or a braze-welded joint can result in a stronger joint than traditional welding because of the difference in melting points between the two materials. If steel is heated to near its melting point then allowed to cool slowly, it becomes weak. With either of these techniques, the steel never gets hot enough to be damaged.