Intake Manifold Sulphur Corrosion & Recall (2002–2003)

Symptoms

• Hot exhaust gases may escape from an internal passage at the very rear of the engine if the manifold burns through [0].
• Exhaust leak in this location directs extremely hot gases toward the firewall insulation [0].
• A rubber fuel return line — where the injector return and rail solenoid return meet at a banjo fitting — is exposed to heat risk from this failure [0].
• White smoke increasing as the engine warms up may indicate a separate but related issue: coolant ingestion at the intake manifold mating surface or EGR-to-manifold gasket [2].
• Blocked or restricted EGR port at the EGR valve may accompany manifold issues on affected vehicles [3].

Causes

• Acidic/sulphur corrosion erodes an internal exhaust passage cast into the rear of the aluminum intake manifold [0, 4].
• The manifold's aluminum construction is vulnerable to long-term chemical attack from sulphur compounds in diesel exhaust gases recirculated through the EGR system [4].
• Manifold warpage or surface irregularities at the water jacket interface can allow coolant to enter the intake tract [2].
• A degraded or improperly seated EGR-to-manifold gasket can contribute to leaks at the manifold [2].

Diagnosis

• Check whether your 2002–2003 Sprinter has had NHTSA Recall #48920 completed — if not, the manifold may still be the original susceptible casting [4].
• Inspect the very rear of the intake manifold for signs of discoloration, heat damage, or exhaust soot, which would indicate burn-through of the internal exhaust passage [0].
• Verify the proximity of the fuel return banjo fitting (where injector return and rail solenoid return lines meet) to the rear of the manifold for signs of heat exposure [0].
• If white smoke is present and increases as the engine warms up, remove the manifold and inspect mating surfaces for warpage or irregularities at the water jacket connection [2].
• Pressurize the cooling system and inspect with a borescope into the manifold to check for coolant intrusion, or inspect the EGR-to-manifold gasket for failure [2].

Repair

The primary repair for 2002–2003 vehicles is dealer-performed replacement of the intake manifold under NHTSA Recall #48920. The recall involves replacing the manifold due to sulphur corrosion of an internal exhaust passage. At least one Freightliner dealership also replaced the EGR valve at no charge during the recall procedure, though this may not be universal practice. Improper installation technique during manifold replacement has been reported as a source of additional engine damage, so correct procedure is critical.

Parts

Plain part names — affiliate links and pricing are coming in a later update.

• Replacement intake manifold (recall-supplied for eligible 2002–2003 vehicles, NHTSA Recall #48920)
• EGR valve (may be replaced concurrently with manifold — confirm with dealer) [5]
• EGR-to-manifold gasket [2]
• Manifold-to-head gasket/sealing surfaces (inspect for warpage before reuse) [2]

Related forum threads

• 19 ↳'02-'03 Active Recall
• 19 ↳2nd time for glow plugs
• 18 ↳Messed up Intake Manifold Replacement?
• 15 ↳Looking at a 2003- special thing a to look out for?
• 14 ↳White smoke - Oil or Coolant???

Sources