NOTE: Before performing EFE test, allow engine coolant temperature to cool to below 40°F (4°C).

Locate EFE valve and note position of actuator arm. On some V8 engines, EFE valve actuator arm is protected by a 2-piece metal cover, which must be removed and then replaced after service has been performed.
Valve should close when engine is started cold. Actuator link will be pulled into diaphragm housing. If valve does not close, stop engine and remove vacuum hose from EFE valve.
Using a hand vacuum pump, apply at least 10 in. Hg of vacuum. Valve should close and remain closed for at least 20 seconds without applying additional vacuum. Replace valve if leakdown time is less than 20 seconds.
If valve does not close, lubricate valve with manifold heat valve lubricant (1050422). Replace valve if necessary. If valve did not close when vacuum was applied and valve is not seized, vacuum diaphragm is defective. Replace EFE valve.
If valve closed, problem is not in EFE valve. Check for loose, kinked, pinched or plugged vacuum hoses or connections. Also check TVS, vacuum solenoid or relay.

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.

Safety Warning

Vacuum Servo Quick Check