For 1990-2009 cars

# Use of Chrome or Chrome-Plated Steel Valve Caps on Aluminum Valve Stems

Subject: | Use of Chrome or Chrome Plated Steel Valve Caps on Aluminum Valve Stems

Models: | 2009 and Prior GM Passenger Cars and Light DutyTrucks (including Saturn)

| 2009 and Prior HUMMER H2, H3

| 2009 and Prior Saab 9-7X

This bulletin is being issued to inform dealers about the use of chrome or chrome-plated steel valve caps on aluminum valve systems.

Dealers/customers cannot install a chrome or chrome-plated steel valve cap on an aluminum valve system. If this happens, the contact between the different metals results in galvanic corrosion, which will seize the cap to the stem and may fracture the stem when attempting to remove the cap.

Inform customers of corrosion issues when chrome or chrome-plated steel valve caps are used on aluminum valve stems.

Use only plastic or aluminum caps with aluminum valve systems.