Exhaust Pipe - Rear Section

This procedure covers the removal and installation of the rear exhaust pipe section on a 2016-2021 Honda Civic 1.5L Turbo, from the mid-pipe flange to the rear muffler outlet.

Warnings

Tools required

Parts

• Rear exhaust pipe section × 1 — 18310-5AA-A00 or equivalent
• Exhaust flange gasket × 1 — Use OEM specification
• Rubber exhaust hangers (if deteriorated) × 2 — Use OEM specification

Preparation

1. Ensure the vehicle has not been driven for at least 2 hours to allow exhaust system to cool completely
2. Park on level ground and apply parking brake firmly
3. Place wheel chocks behind the rear wheels
4. Raise the rear of the vehicle using a floor jack at the rear subframe jacking points
5. Support the vehicle on jack stands placed at the rear subframe pinch welds rated for the vehicle weight
6. Spray all exhaust flange bolts and hanger bolts with penetrating oil and allow to soak for 10-15 minutes

Procedure

1. 1

   Inspect exhaust routing and components
   Locate the rear exhaust section which runs from the mid-pipe flange connection (approximately under the rear seats) to the rear bumper. Identify the flange connection point, two rubber exhaust hangers, and any heat shields attached to this section. Take photos for reference during reinstallation if desired.
2. 2

   Remove heat shield (if equipped)
   If a heat shield is present over the rear exhaust section, remove the mounting bolts using a 10mm socket. There are typically 2-3 bolts securing the shield. Set the heat shield and bolts aside for reinstallation.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
3. 3

   Support the rear exhaust section
   Place a jack or adjustable jack stand under the rear muffler section to support its weight. Position it to prevent the exhaust from falling once the hangers and flange are disconnected. Raise slightly to take tension off the rubber hangers.
4. 4

   Disconnect rubber exhaust hangers
   Using a pry bar or large flathead screwdriver, carefully pry the rubber exhaust hangers off their mounting hooks on the vehicle body. There are typically two hangers on the rear section. Work the rubber isolator off the metal hook by pushing the exhaust pipe to create slack. Inspect hangers for cracks or deterioration and replace if necessary.
5. 5

   Remove exhaust flange bolts
   Locate the flange connection between the mid-pipe and rear section (two-bolt spring-loaded flange). Using a 14mm socket, remove both flange bolts while holding the nuts on the opposite side if accessible. The flange may have a spring-loaded design to maintain tension. Keep track of any springs, washers, or spacers.
   ⚠If bolts are severely corroded and begin to strip, stop and apply more penetrating oil or apply heat carefully with a torch, keeping flammable materials away.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Separate flange connection
   Once bolts are removed, carefully separate the flange connection by pulling the rear section rearward and downward. The flange may be stuck due to carbon buildup. Use a pry bar if needed to separate the joint. Remove the old exhaust gasket from the flange and discard it.
7. 7

   Remove rear exhaust section
   With the flange disconnected and hangers removed, carefully lower the rear exhaust section using the support jack and remove it from under the vehicle. Avoid damaging the rear bumper or underbody components during removal.
8. 8

   Clean flange surfaces
   Using a wire brush, thoroughly clean the flange surface on the mid-pipe where the new rear section will connect. Remove all carbon deposits, old gasket material, and corrosion to ensure a proper seal. Clean the flange on the new rear section as well if not already clean.
9. 9

   Prepare new rear section
   Install a new exhaust flange gasket onto the flange connection point. Apply a thin layer of anti-seize compound to the flange bolt threads as specified. Do not apply anti-seize to the gasket surfaces themselves.
10. 10

    Position new rear exhaust section
    Lift the new rear exhaust section into position using the support jack. Align the flange with the mid-pipe connection point and ensure the exhaust hangers are positioned near their mounting hooks. The tailpipe outlet should be centered in the rear bumper cutout.
11. 11

    Install flange bolts hand-tight
    Insert the flange bolts through the flange connection with the gasket properly seated. Thread the nuts onto the bolts by hand and tighten finger-tight only at this stage. Ensure the flange is properly aligned and the gasket is not pinched or misaligned.
12. 12

    Connect rubber exhaust hangers
    Push the exhaust pipe hangers onto the body-mounted hooks. Use a lubricant like soapy water on the rubber hangers to ease installation if needed. Ensure both hangers are fully seated on their hooks. Adjust the position of the exhaust so it hangs evenly and the tailpipe is properly positioned in the bumper cutout.
13. 13

    Torque flange bolts to specification
    Using a torque wrench and 14mm socket, torque the exhaust flange bolts to 45 Nm (33 lb-ft) in an alternating pattern to ensure even clamping pressure on the gasket. Verify both bolts are torqued properly.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
14. 14

    Reinstall heat shield
    If a heat shield was removed, position it back over the exhaust section and install the mounting bolts. Torque the heat shield bolts to 10 Nm (7 lb-ft) using a 10mm socket and torque wrench. Ensure the heat shield does not contact the exhaust pipe directly.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
15. 15

    Final inspection and clearance check
    Remove the support jack from under the exhaust. Visually inspect all connections to ensure fasteners are tight and hangers are properly seated. Check for adequate clearance between the exhaust system and all underbody components, fuel lines, brake lines, and suspension components. The exhaust should not contact any part of the vehicle body. Verify the tailpipe position in the rear bumper is centered and aesthetically acceptable.

Reassembly

1. Lower the vehicle carefully from jack stands and remove wheel chocks
2. Do not perform a final clearance verification until after the first test drive, as the exhaust may shift slightly under load

Verification

• Start the engine and listen for exhaust leaks at the flange connection. A leak will produce a ticking or hissing sound that increases with engine RPM
• With the engine running, carefully feel around the flange connection for escaping exhaust gases (do not touch hot components)
• Take a short test drive and listen for any rattling, buzzing, or contact noises from the exhaust system
• After the test drive, allow the exhaust to cool and recheck all fastener torque values
• Perform a final visual inspection under the vehicle to confirm proper clearances and hanger engagement
• Verify the tailpipe position remains centered in the rear bumper cutout

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