How to Remove the Front Exhaust Pipe & Catalytic Converters 1990-1994 Lexus LS400

By Andy Vogel

Before doing anything read my disclaimer & safety info.

Notes

The exhaust system is prone to rust since it's exposed to everything you drive through. Even though removing the exhaust pipes is only a few nuts and bolts they will probably be rusted on. The repair manual recommends replacing all nuts, bolts, and gaskets when the exhaust is removed. The nuts & bolts may break while removing, or you may need to cut them off in order to remove the pipe. Be ready in case of this. You may be able to get by with reusing these parts, but the gaskets must be replaced. Please direct any questions and feedback regarding this tutorial to Andy, not LexLS.

Tools Needed:

Box wrenches
Socket Set
Torque wrench
WD-40 or Liquid wrench
Optional: Grinder to cut nuts/bolts off

Parts Needed:

2 Gasket, front y-pipe
1 Gasket, rear y-pipe
4 Nuts, front y-pipe
4 bolts, front y-pipe
2 Nuts, rear y-pipe
2 bolts, rear y-pipe
6 Bolts, cat converter
6 Nuts, cat converter
2 Gaskets, cat converter

1) Remove the two rear oxygen sensors. You don't have to unplug them unless you're replacing them.

2) If you're going to remove the entire exhaust then start in the back with the tail pipes and work your way toward the front. In this case we're only showing removal of the front pipe and cats so it's not necessary to remove the tail pipes.

Remove the 2 sets of bolts for each exhaust pipe. Torque = 32 ft-lb (43 Nm). Use some WD-40 to get the two nuts loose on both sides at the rear of the catalytic converters, including the covers of the O2-sensors. If you're going to be removing the transmission then also remove the steering damper (already removed on this picture, red highlights show where the bolts go).

3) Remove the two bolts at the rear of the front Y-pipe and set it aside. Torque = 32 ft-lb (43 Nm). Remove the heat shieldings if you're going to remove the driveshaft.

4) Unscrew the three nuts and bolts at the front of the catalytic converters. Torque = 46 ft-lb (62 Nm).

5) I broke two of the 6 bolts. With some effort I could remove and substitute them.

6) Install is reverse of removal. Here's a picture of the old gasket, it doesn't look good, replace all gaskets!

Support LexLS.com

If you found this information useful please support the site by clicking the button below and making a donation. Thank you.