11 - Exhaust System - 2012 Jeep Wrangler JK Factory Service Manual

GAS ENGINES

EXHAUST SYSTEM - TYPICAL - GAS ENGINES

1 - EXHAUST FLANGE

2 - CATALYTIC CONVERTER

3 - FRONT EXHAUST PIPE ASSY-TO-MUFFLER FLANGE

4 - MUFFLER

5 - INSULATOR

The basic exhaust system consists of a exhaust pipe assembly with catalytic converters (2), muffler (4) and tailpipe assembly and heat shields.

The exhaust system must be properly aligned to prevent stress, leakage and body contact. Minimum clearance between any exhaust component and the body or frame is 25 mm (1.0 in.). If the system contacts any body panel, it may amplify objectionable noises from the engine or body.

When inspecting an exhaust system, critically inspect for cracked or loose joints, stripped screw or bolt threads, corrosion damage and worn, cracked or broken hangers. Replace all components that are badly corroded or damaged. DO NOT attempt to repair.

When replacement is required, use original equipment parts (or equivalent). This will assure proper engine function and system alignment.

CAUTION:

Avoid application of rust prevention compounds or undercoating materials to exhaust system floor pan exhaust heat shields. Light overspray near the edges is permitted. Application of coating will result in excessive floor pan temperatures and objectionable fumes.

2.8L DIESEL

CAUTION:

Avoid application of rust prevention compounds or undercoating materials to exhaust system floor pan exhaust heat shields. Light overspray near the edges is permitted. Application of coating will result in excessive floor pan temperatures and objectionable fumes.

The diesel engine exhaust system consists of an engine exhaust manifold, turbocharger, EGR valve with intercooler, front exhaust pipe with catalytic converter, muffler and tailpipe assembly.

The exhaust system must be properly aligned to prevent stress, leakage and body contact. The exhaust components should be kept a minimum of 25.4 mm (1.0 in.) away from the body and frame. If the system contacts any body panel, it may amplify objectionable noises from the engine or body.

DIAGNOSIS AND TESTING - GAS ENGINE

EXHAUST SYSTEM DIAGNOSIS CHART

CONDITION

POSSIBLE CAUSE

CORRECTION

Excessive Exhaust Noise or Leaking Exhaust Gases

1. Leaks at pipe joints.

1. Tighten clamps/bolts to specified torque at leaking joints.

2. Rusted or blown out muffler.

2. Replace muffler. Inspect exhaust system.

3. Broken or rusted out exhaust pipe.

3. Replace exhaust pipe.

4. Exhaust pipe leaking at manifold flange.

4. Tighten/replace flange attaching nuts/bolts.

5. Exhaust manifold cracked or broken.

5. Replace exhaust manifold.

6. Leak between exhaust manifold and cylinder head.

6. Tighten exhaust manifold to cylinder head bolts.

7. Catalytic converter rusted or blown out.

7. Replace catalytic converter assembly.

8. Restriction in exhaust system.

8. Remove restriction, if possible. Replace restricted part if necessary.

CAUTION:

When servicing and/or replacing exhaust system components, disconnect the oxygen sensor connector(s). Allowing the exhaust to hang by the oxygen sensor wires will damage the harness and/or oxygen sensor.

DIESEL ENGINE

CAUTION:

On high mileage vehicles it is normal to see some exhaust staining around the turbocharger control rod area. This is not a sign of turbocharger failure.

EXHAUST SYSTEM DIAGNOSIS CHART

CONDITION	POSSIBLE CAUSE	CORRECTION
EXCESSIVE EXHAUST NOISE OR LEAKING EXHAUST GASES	1. Leaks at pipe joints.	1. Tighten clamps/bolts at leaking joints.
	2. Rusted or blown out muffler.	2. Replace muffler. Inspect exhaust system.
	3. Broken or rusted out exhaust pipe.	3. Replace exhaust pipe.
	4. Exhaust pipe leaking at manifold flange.	4. Tighten/replace flange attaching nuts/bolts.
	5. Exhaust manifold cracked or broken.	5. Replace exhaust manifold.
	6. Leak between exhaust manifold and cylinder head.	6. Tighten exhaust manifold to cylinder head bolts. Replace gasket if necessary.
	7. Turbocharger mounting flange cracked.	7. Remove turbocharger and inspect. (Refer to 9 - ENGINE/MANIFOLDS/EXHAUST MANIFOLD - REMOVAL).
	8. Restriction in exhaust system.	8. Remove restriction, if possible. Replace restricted part if necessary.
	9. EGR pipe(s) leak.	9. Tighten bolts. Replace gasket.
	10. EGR assembly leak.	10. Tighten bolts. Replace gaskets.
Drivability Concern - Turbo	1. Vacuum hose disconnected.	1. Check connections, replace as necessary.
	2. Vacuum system leaks.	2. Inspect for damage. Check for leaks, replace as necessary.
	3. Boost pressure solenoid filter clogged.	3. Replace the filter.

SPECIFICATIONS

DESCRIPTION	N·m	Ft. Lbs.
Bolts, Crossmember to Sill	42	31
Nuts, Crossmember to Transmission Mount	22	16
Nuts/Bolt, Exhaust Manifold to Engine	36	27
Nuts, Exhaust Pipe to Catalytic Converter Flange	27	19
Nuts, Catalytic Converter to Turbocharger	27	19
Bolt, DPF to Catalytic Converter	32	24
Bolts, DPF to Muffler	32	24
Clamp, Tailpipe to Rear Tailpipe Hanger	27	20
Oxygen Sensors	50	37
Heat Shields	45	33