Subaru Repair: catalytic converter, hose clamps, subaru legacy


Question
Joe; My catalytic converter is making a rattling noise. In the past I have replaced or bypassed the converter to omit this noise on other vehicles I have owned. I wonder; does the rattling mean the converter is not working and if I do take it out will this affect the performance of my engine in gas mileage, etc. This is a '94 Subaru Legacy AWD non-turbo. The noise gets worse every day. I am also confused because there seems to be two converter shaped units on this vehicle. One is close to the engine with the oxygen sensor in it and the other is under the drivers seat, then there is the muffler towards the back of the car. Can you help? Thank you,   Pat

Answer
Pat, stop worrying. The rattling your hearing is most likely a loose heat shield on your cat or on the exhaust pipe. Tightening them up with steel hose clamps usely stops the noise. With the engine off (and cold) tapping the exhaust system with a small hammer(lightly) should reproduce the noise allowing you to find the rattling shield. Your car is equiped with two converters, altering or removing them will cause your car to fail most state inspections and run poorly.