With access to a floor jack and jack stands, check the exhaust system at home on a 1998 Montero. When components in the exhaust system are loose or damaged, you may experience excessive exhaust or rattling noises. If the exhaust piping is disconnected or damaged, this will cause the exhaust gases to leak. Not only will exhaust leaks reduce the Montero's efficiency and performance, they can also allow poisonous gasses to enter the vehicle cabin. This can be dangerous or even fatal to the driver and passengers. Because of this, you should inspect the exhaust system on your Mitsubishi Montero immediately if you think it may be damaged.
Start your 1998 Montero and step outside of the vehicle. Listen along the lower side of the vehicle for exhaust hissing or popping noises, as these likely indicate an exhaust leak. Also, be aware of any excessive exhaust gas smells present while the engine is running.
Park the vehicle on a flat and solid concrete surface. Allow ample time for the engine and exhaust system to cool off before you begin inspection. Then, use a floor jack to raise the rear of the vehicle. Support the chassis by placing jack stands underneath each side of the vehicle.
Inspect the full exhaust system piping for signs of rust or damage. While minor rust forming on the piping over time is common, extensive rust that compromises the integrity of the piping must be addressed. If there are any rust spots or other damage that create holes in the exhaust piping, have the damaged section replaced immediately.
Check the exhaust hangers which secure the exhaust system to the underside of the chassis. Rubber hangers are located throughout the exhaust system, connecting the metal exhaust hooks to brackets mounted along the chassis. A damaged rubber hanger may allow the exhaust to rattle or come unaligned. Additionally, check the metal hooks and chassis brackets for signs of damage, such as stress cracks.
Use a socket wrench to check that the exhaust flange bolts are secure. There are two bolts located at each flange connection throughout the exhaust system. All of the bolts must be extremely tight to ensure an airtight seal. If you still experience exhaust leaks at the flange locations after tightening the bolts, replace the rubber gaskets located between each exhaust flange with new units.
Lower the vehicle off of the floor jack after removing the jack stands from under the chassis. Open the vehicle hood and inspect the exhaust manifold, located on the left side of the engine. Carefully check the manifold piping and welds for signs of cracking. With the hood still open, start the engine and listen carefully to the exhaust manifold for hissing or popping noises. These noises indicate an exhaust leak in the manifold or piping, likely due to a crack that is not visible.