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Autopapyrus · Peugeot Boxer 2.0 BlueHDi (2017)
https://autopapyrus.com/guides/peugeot/boxer/diagnosing-intake-air-leaks-and-replacing-the-boost-hoses-and-intake-manifold/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Peugeot Boxer 2.0 BlueHDi (2017): Diagnosing Intake Air Leaks and Replacing the Boost Hoses and Intake Manifold Gasket

An air leak or boost leak on the 2.0 diesel shows up as loss of power, smoke, unstable idle, and fault codes for boost pressure or airflow. First find where the leak is, because cracked hoses and clamps are more often to blame than the manifold gasket itself.

Difficulty: Medium Time: 2-4 hours Steps: 11 Tools: socket and wrench set (Torx and hex bits), screwdrivers, torque wrench, hose clamp pliers, flashlight, smoke machine or manual intake pressure tester (recommended), throttle body cleaner, shop rags, plugs for open ports

Part

  • 🔩 Intake manifold gasket (set with new seals), turbo-intercooler charge air hoses (pressure hoses carrying air from the turbo to the intercooler and from the intercooler to the manifold), air filter hose after the mass airflow sensor, clamps, hose O-rings. The exact part numbers for your engine version have not been confirmed, so order by part name and compare the new part visually with the one you removed
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes AutoFix (online) and 1 more. See manuals →

Step by step

11 steps
  1. Preparation. Work on a cold engine. Disconnect the negative battery terminal and remove the engine cover. Take photos of how the hoses and connectors are routed so you can reassemble everything the same way.
  2. Visual inspection. Check the whole air path from the air filter housing to the intake manifold. Look for cracks, rubber delamination, oil seepage at the joints, and clamps that have slipped or loosened. An oily film at a joint almost always indicates a boost leak.
  3. Leak test. The best method is to feed smoke or a small amount of air pressure (about 0.3-0.5 bar) into the air path through a temporary plug, after disconnecting the hose at the turbo. Leaks show up as smoke, or you can find them with soapy water. Do not exceed this pressure, or you may damage the sensors and diaphragms.
  4. Removing the hoses. Loosen the clamps and disconnect the sensor connectors (mass airflow sensor, boost pressure and temperature sensor). Gently press in the plastic locking tabs, because they are brittle. Remove each hose by rocking it back and forth, and do not pull on the plastic fittings.
  5. Replacing the hoses. Compare the new hose with the old one for length, diameters, and fittings. Wipe the mating surfaces clean of oil and carbon deposits. Install new O-rings and new clamps if the old ones are deformed. Tighten the clamps moderately and evenly, without letting them sit crooked.
  6. Removing the intake manifold, if the leak is at its mating surface. Disconnect all hoses, electrical connectors, vacuum lines, and brackets on the manifold. If the fuel rail or fuel lines are in the way, do not disconnect the high-pressure fuel lines unless you have to, and keep everything clean, because dirt must never get into a Common Rail system. Cover the open intake ports of the cylinder head with clean rags or plugs so nothing falls into the cylinders.
  7. Loosen the manifold fasteners in a criss-cross pattern, starting with the middle bolts, and remove the manifold. Inspect it for cracks and carbon buildup. If the manifold has swirl flaps or an EGR valve, clean off the carbon with a dedicated cleaner.
  8. Clean the mating surfaces of the cylinder head and the manifold without scratching them, then fit a new gasket. Do not reuse the old gasket.
  9. Install the manifold. Tighten the bolts in a criss-cross pattern from the center outward in two passes. The torque spec is not confirmed. As a rough guide, fasteners like these are typically 8-12 N·m (6-9 lb-ft), but get the exact value from the manufacturer's specifications for your engine.
  10. Reinstall all hoses, connectors, and vacuum lines in reverse order, following the photos you took. Check that all clamps and locking tabs are in place and that the plastic latches have clicked into place.
  11. Final check. Reconnect the battery, warm up the engine, and listen for hissing or whistling at idle and when you raise the revs, and also under load. Repeat the smoke or pressure test. Read and clear the fault codes with a diagnostic scanner, then take a test drive under load and make sure the power is back and the codes do not return.

Common mistakes and warnings

  • An air leak upstream of the turbo (in the air path after the air filter) can pull dust and debris into the turbo and the engine, so do not put off the repair. When working on the Common Rail fuel system, do not open the high-pressure lines while the engine is running or hot, and keep everything clean. If you lack experience, have a repair shop remove the manifold.