What is the purpose of the Positive Crankcase Ventilation (PCV) system and PCV Valve on Mercury Grand Marquis?

The Positive Crankcase Ventilation (PCV) system reduces emissions by circulating fresh air from the air cleaner through the crankcase, mixing with gases, and rerouting through a PCV valve to the intake manifold. The system includes a PCV valve, a fresh air inlet, and vacuum hoses. The PCV valve restricts flow to maintain idle quality. If anything odd occurs, the system allows excess gases to flow back into the air cleaner. It is required that regular checking and replacement of the PCV valve happens.

How to check the PCV Valve on Mercury Grand Marquis?

To maintain efficient operation of the PCV system, clean the hoses and check the PCV valve at the intervals recommended in the maintenance schedule. The PCV valve is located in the right (passenger's side) valve cover. Check the valve by first pulling it out of the valve cover. Late models are equipped with push-connect fittings on the PCV hoses - rotate the tab to unlock the fitting. Shake it - if it rattles, reinstall it in the cover. Start the engine and allow it to idle, then disconnect the PCV hose from the air cleaner housing and feel for vacuum at the hose. If vacuum is felt, the PCV valve/system is working properly. If no vacuum is felt, the oil filler cap, hoses, or valve cover gasket may be leaking or the PCV valve may be bad. Check for vacuum leaks at the valve, filler cap, and all hoses. Pull straight up on the valve to remove it. Check the rubber grommet in the rocker arm cover for cracks and distortion. If it's damaged, replace it. If the valve is clogged, the hose is also probably plugged. Remove the hose between the valve and the intake manifold and clean it with solvent. After cleaning the hose, inspect it for damage, wear, and deterioration. Make sure it fits snugly on the fittings. If necessary, install a new PCV valve. Install the clean PCV system hose. Make sure that the PCV valve and hose are secure.

Genuine Mercury Grand Marquis PCV Valve

Position Crank Ventilation Valve

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13 PCV Valves found

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Mercury Grand Marquis Valve Assembly
Part Number: E1DZ-6A666-A
$19.42 MSRP: $34.18
You Save: $14.76 (44%)
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1980-1986 Mercury Grand Marquis | 8 Cyl 4.2L, 8 Cyl 5.0L, 8 Cyl 5.8L | 3AT, 3AT C4, 3AT C6, 4AT AOD
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Mercury Grand Marquis Valve Assembly
Part Number: 7L3Z-6A666-A
$20.98 MSRP: $33.45
You Save: $12.47 (38%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Manufacturer Note: Valve Only
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2009-2011 Mercury Grand Marquis | 8 Cyl 4.6L Romeo SOHC EFI | 4-Speed Automatic Transmission 4R75E Livonia, Left Hand Drive, Rear-Wheel Drive (Left Hand Drive)
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Mercury Grand Marquis Valve Assembly
Part Number: 2X4Z-6A666-AA
$8.44 MSRP: $13.45
You Save: $5.01 (38%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2003-2006 Mercury Grand Marquis | 8 Cyl 4.6L | 4AT 4R70W
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Mercury Grand Marquis Valve Assembly
Part Number: 6W7Z-6A666-AA
$64.79 MSRP: $107.09
You Save: $42.30 (40%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2007-2009 Mercury Grand Marquis | 8 Cyl 4.6L Romeo SOHC EFI | 4-Speed Automatic Transmission 4R75E Livonia, Left Hand Drive, Rear-Wheel Drive (Left Hand Drive)
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Mercury Grand Marquis Valve Assembly
Part Number: 2L3Z-6A666-AA
$17.44 MSRP: $27.82
You Save: $10.38 (38%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Replaces: 2L3Z-6A666-BA
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2003-2004 Mercury Grand Marquis | 8 Cyl 4.6L | 4AT 4R70W
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Mercury Grand Marquis Valve Assembly
Part Number: 5L3Z-6A666-BA
$78.43 MSRP: $129.64
You Save: $51.21 (40%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2005-2006 Mercury Grand Marquis | 8 Cyl 4.6L | 4AT 4R70W
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Mercury Grand Marquis Valve Assembly
Part Number: E5ZZ-6A666-A
$14.86 MSRP: $23.09
You Save: $8.23 (36%)
Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1984-1989 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 4AT AOD
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Mercury Grand Marquis Valve Assembly
Part Number: D9OZ-6A666-A
Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1980-1981 Mercury Grand Marquis | 8 Cyl 4.2L, 8 Cyl 5.0L, 8 Cyl 5.8L | 3AT, 3AT C4, 3AT C6, 4AT AOD
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Mercury Grand Marquis Valve Assy - Regulating
Part Number: F33Z-6A666-A
Product Specifications
- Other Name: PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1988-1989 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 4AT AOD
View related parts
Mercury Grand Marquis Valve Assembly
Part Number: D9ZZ-6A666-A
Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1980-2002 Mercury Grand Marquis | 8 Cyl 4.2L, 8 Cyl 4.6L, 8 Cyl 5.0L, 8 Cyl 5.8L | 3AT, 3AT C4, 3AT C6, 4AT, 4AT 4R70W, 4AT AOD, 4AT AODE
View related parts
Mercury Grand Marquis Valve Assembly
Part Number: D9BZ6A666A
Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1980 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 3AT, 3AT C4, 3AT C6, 4AT AOD
View related parts
Mercury Grand Marquis Valve Assembly
Part Number: D9DZ-6A666-A
Product Specifications
- Other Name: Valve Assy; PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1983-1984 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 4AT AOD
- 1980 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 3AT, 3AT C4, 3AT C6, 4AT AOD
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Mercury Grand Marquis SHIELD - FUEL TUBES
Part Number: E7GZ6A666A
Product Specifications
- Other Name: PCV Valve
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1987-1989 Mercury Grand Marquis | 8 Cyl 5.0L, 8 Cyl 5.8L | 4AT AOD

Mercury Grand Marquis PCV Valve Parts Questions & Experts Answers

Valve Assembly
2L3Z-6A666-AA
Q: What is the purpose of the Positive Crankcase Ventilation (PCV) system and PCV Valve on Mercury Grand Marquis?
A: The Positive Crankcase Ventilation (PCV) system reduces emissions by circulating fresh air from the air cleaner through the crankcase, mixing with gases, and rerouting through a PCV valve to the intake manifold. The system includes a PCV valve, a fresh air inlet, and vacuum hoses. The PCV valve restricts flow to maintain idle quality. If anything odd occurs, the system allows excess gases to flow back into the air cleaner. It is required that regular checking and replacement of the PCV valve happens.
Valve Assembly
2X4Z-6A666-AA
Q: How to check the PCV Valve on Mercury Grand Marquis?
A: To maintain efficient operation of the PCV system, clean the hoses and check the PCV valve at the intervals recommended in the maintenance schedule. The PCV valve is located in the right (passenger's side) valve cover. Check the valve by first pulling it out of the valve cover. Late models are equipped with push-connect fittings on the PCV Hoses - rotate the tab to unlock the fitting. Shake it - if it rattles, reinstall it in the cover. Start the engine and allow it to idle, then disconnect the PCV hose from the air cleaner housing and feel for vacuum at the hose. If vacuum is felt, the PCV valve/system is working properly. If no vacuum is felt, the oil filler cap, hoses, or valve cover gasket may be leaking or the PCV valve may be bad. Check for vacuum leaks at the valve, filler cap, and all hoses. Pull straight up on the valve to remove it. Check the rubber grommet in the rocker arm cover for cracks and distortion. If it's damaged, replace it. If the valve is clogged, the hose is also probably plugged. Remove the hose between the valve and the intake manifold and clean it with solvent. After cleaning the hose, inspect it for damage, wear, and deterioration. Make sure it fits snugly on the fittings. If necessary, install a new PCV valve. Install the clean PCV system hose. Make sure that the PCV valve and hose are secure.