Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Installation

INSTALLATION

PROCEDURE

1. INSTALL STUD BOLT

HINT:

If a stud bolt is deformed or its threads are damaged, replace it.

(a) Using an E8 "TORX" socket wrench, install the 2 stud bolts to the exhaust manifold (TWC: Front Catalyst). Torque: 19.5 N·m {199 kgf·cm, 14 ft·lbf}

(b) Using an E8 "TORX" socket wrench, install the 2 stud bolts to the exhaust manifold assembly LH (TWC: Front Catalyst). Torque: 19.5 N·m {199 kgf·cm, 14 ft·lbf}

2. INSTALL EXHAUST MANIFOLD TO HEAD GASKET (for Bank 2)

(a) Install a new exhaust manifold to head gasket to the cylinder head sub-assembly.

3. INSTALL EXHAUST MANIFOLD ASSEMBLY LH (TWC: Front Catalyst)

(a) Temporarily install the exhaust manifold assembly LH (TWC: Front Catalyst) with the 4 nuts.

(b) Temporarily install the No. 2 manifold stay to the exhaust manifold assembly LH (TWC: Front Catalyst) and cylinder block sub-assembly with the bolt and nut.

(c) Using a 12 mm deep socket wrench, tighten the 4 nuts in the order shown in the illustration. Torque: 21 N·m {214 kgf·cm, 15 ft·lbf}

(d) Tighten the bolt and nut in the order shown in the illustration.

	Bolt
	Nut

Torque:

34 N·m {347 kgf·cm, 25 ft·lbf}

(e) Connect the No. 1 radiator hose to the radiator assembly and slide the clip to secure it.

(f) Connect the 2 No. 2 cooling fan motor connectors.

4. INSTALL AIR FUEL RATIO SENSOR (for Bank 2)

Click here

5. INSTALL NO. 2 EXHAUST MANIFOLD HEAT INSULATOR

(a) Install the No. 2 exhaust manifold heat insulator to the exhaust manifold assembly LH (TWC: Front Catalyst) with the 3 bolts in the order shown in the illustration. Torque: 8.5 N·m {87 kgf·cm, 75 in·lbf}

(b) Engage the wire harness clamp.

(c) Connect the air fuel ratio sensor connector.

6. INSTALL V-BANK COVER SUB-ASSEMBLY

Click here

7. INSTALL ENGINE OIL LEVEL DIPSTICK GUIDE

Click here

8. INSTALL FRONT EXHAUST PIPE ASSEMBLY

Click here

9. INSTALL NO. 1 EXHAUST PIPE SUPPORT BRACKET (for Lower Side)

Click here

10. INSTALL EXHAUST MANIFOLD TO HEAD GASKET (for Bank 1)

(a) Install a new exhaust manifold to head gasket to the cylinder head sub-assembly RH.

11. INSTALL EXHAUST MANIFOLD (TWC: Front Catalyst)

(a) Temporarily install the exhaust manifold (TWC: Front Catalyst) with the 4 nuts.

(b) Temporarily install the manifold stay to the exhaust manifold (TWC: Front Catalyst) and rear engine mounting bracket with the bolt and nut.

(c) Using a 12 mm deep socket wrench, tighten the 4 nuts in the order shown in the illustration. Torque: 21 N·m {214 kgf·cm, 15 ft·lbf}

(d) Tighten the bolt and nut in the order shown in the illustration.

Torque:

34 N·m {347 kgf·cm, 25 ft·lbf}

	Bolt
	Nut

12. INSTALL FRONT NO. 3 EXHAUST PIPE SUB-ASSEMBLY

(a) Using a vernier caliper, measure the free length of the 2 compression springs. Standard Length 43.0 mm (1.69 in.) Minimum Free Length 41.5 mm (1.63 in.) If the free length is less than minimum, replace the compression spring.

(b) Temporarily install a new exhaust pipe gasket to the front No. 3 exhaust pipe sub-assembly (center exhaust pipe assembly (TWC: Rear Catalyst) side).

(c) Using a plastic hammer and wooden block, tap in the exhaust pipe gasket until its surface is flush with the front No. 3 exhaust pipe sub-assembly. NOTICE: Be careful with the installation direction of the exhaust pipe gasket. Do not reuse the exhaust pipe gasket. Do not damage the exhaust pipe gasket. Do not push in the exhaust pipe gasket by using the exhaust pipes when connecting them.

*1 Front No. 3 Exhaust Pipe Sub-assembly *2 Exhaust Pipe Gasket *a Wooden Block

(d) Install 2 new exhaust pipe gaskets to the front No. 3 exhaust pipe sub-assembly.

(e) Temporarily install the front No. 3 exhaust pipe sub-assembly with the 4 bolts, 2 nuts and 2 compression springs.

(f) Tighten the 2 bolts and 2 nuts.

Torque:

55 N·m {561 kgf·cm, 41 ft·lbf}

(g) Tighten the 2 bolts and 2 compression springs.

Torque:

43 N·m {438 kgf·cm, 32 ft·lbf}

HINT:

After installation, check that the space between the flanges of the center exhaust pipe assembly (TWC: Rear Catalyst) and front No. 3 exhaust pipe sub-assembly is consistent front-to-rear and left-to-right.

(h) Connect the heated oxygen sensor (for Bank 1) connector.

(i) Engage the 4 wire harness clamps.

13. INSTALL FRONT FLOOR COVER LH

(a) Install the front floor cover LH with the 2 clips (B).

*A	for TMC Made
*B	for TMMC Made
	Bolt
	Screw

(b) Install the clip (A), 2 screws and 4 bolts to the front floor cover LH.

14. INSTALL AIR FUEL RATIO SENSOR (for Bank 1)

Click here

15. INSTALL NO. 2 ENGINE UNDER COVER

Click here

16. ADD ENGINE COOLANT

Click here

17. INSPECT FOR COOLANT LEAK

Click here

18. INSPECT FOR EXHAUST GAS LEAK

Click here