Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

1980 Buick Skyhawk Base, Automatic TransFACTORY OEM SERVICE PROCEDURE

Back Pressure EGR System: Notes

Two types of back pressure type EGR valves are used by General Motors: a Positive Back Pressure EGR valve and a Negative Back Pressure EGR valve. Operation of these two systems is explained as follows:

Fig 1: Cutaway View of Positive Back Pressure EGR Valve

Courtesy of GENERAL MOTORS COMPANY

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.

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