Saving the Heads

December 16, 2006 | Reply More

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You can become a hero to any customer who owns a BMW with either the M62TU or S62 V8 engine that has a clogged secondary air system.

These engines are used on 7 Series (E38), 5 Series (E39), X5 (E53), and Z8 models. Instead of a staggering bill for replacing the plugged head castings, you can restore the passages by cleaning them.

There’s even a nostalgic benefit for you — the chance to actually fix something. Yes, we can recite all the reasons why service work now is mostly diagnose and replace, instead of repair. But we still find a strong sense of personal satisfaction when we repair something and return it to working condition rather than removing the old part and installing a new one.

the kit

The Kit

Clogged air passages typically set a BMW fault code 80 or 81. Start by checking the operation of the air pump, one-way valve, solenoid valve, and other components. If all parts are operating properly, then the passages are plugged.

According to BMW, clogged air passages can occur at any time after the engine has 35,000 miles or more on the odometer. The primary culprit is burning low-grade gas that doesn’t have an adequate amount of detergent additives. BMW currently recommends that its customers only use“Top Tier” gasoline. A list of oil companies that dispense “Top Tier” gasoline can be found at www.toptiergas.com.

The Kit

regulator knob

1. Turn the red regulator knob counterclockwise until fully open.

You will need BMW’s special tool kit, PN 99 00 0 006 668, to clean the secondary air passages on the M62TU or S62 engines. The kit includes:

  • Cylinder head back pressure diagnostic tool
  • Set of 4mm nylon final clean up brushes
  • Core plug installer
  • Core plug remover
  • Drill bit to enable use of core plug remover
  •  Reamer for 4mm air passages.
  • Set of 10mm brass brushes to clean out main air supply passage.

You can order replacement nylon clean up brushes (set of 12, PN 82 11 0 416 754) and replacement brass brushes (set of 3, PN 82 11 0 416 755).  The repair kit does not include replacement 12 mm main secondary air passages core plugs. These plugs must be ordered separately (3 per vehicle, PN11 12 1 736 330).

plug

2. Then insert the plug into the tube and attach an air pressure source.

Calibration

Your initial tests of the air pump, one-way valve, and other components are “diagnosis by elimination.” If all the other components operate properly, the secondary air passages must be plugged. The first step in cleaning the passages is to confirm that the passages are blocked by testing with the Cylinder Head Back Pressure Diagnostic Tool, which is part of the special tool kit.

Open the red knob on the regulator, then insert the plug into the end of the tube and tighten until secure. Attach a pressure gauge or DISplus unit to the fitting on the tool. Connect shop air to the end of the tool.

Open the yellow

 

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Category: BMW TechDrive, Engine Mechanical

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