How to service the Oil Pressure Switch on Mercury Cougar?

The service process of the oil pressure switch starts with disconnecting the battery ground cable. Raise the vehicle before performing support functions. To operate on the oil pressure switch, you need to disconnect the electric connection then take out the oil pressure switch. Reverse the installation process to service the oil pressure switch unit.

How to Service the Engine Oil Pressure Switch on Mercury Mariner?

Start the Engine Oil Pressure (EOP) switch service by hoisting the vehicle to a position while keeping it in the neutral gear. The service requires removal of the five bolts and the pin-type retainer and the right-hand splash shield. The service requires removal of the EOP switch electrical connector and thereafter removal of the switch always applying thread sealant to the switch threads before replacement. The EOP switch should be tightened to 15 Nm (133 lb-in) before reconnecting the electrical connector. Reinstall the splash shield by securing its five bolts at 9 Nm torque.

OEM Mercury Oil Pressure Switch

Oil Pressure Sender Switch

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17 Oil Pressure Switches found

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Mercury Oil Pressure Sensor Part Number: GC3Z-9278-B
$20.27 MSRP: $32.18
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Pressure Switch; Oil Pressure Switch; Pressure Sensor; Sending Unit; Switch Assembly; Oil Gauge
- Replaces: 6U5Z-9278-D, 1U5Z-9278-DA, GC3Z-9278-A, SW-6357
Fits the following Mercury Models:
- Grand Marquis | 2000-2011 | GS, GSL, Limited Edition, LS, LSE, Ultimate Edition | 8 Cyl 4.6 L FLEX, 8 Cyl 4.6 L GAS
- Marauder | 2003-2004 | Base | 8 Cyl 4.6 L GAS
- Mountaineer | 1999-2010 | Base, Convenience, Luxury, Premier | 6 Cyl 4.0 L GAS, 8 Cyl 4.6 L GAS, 8 Cyl 5.0 L GAS
- Sable | 2008-2009 | Base, Premier | 6 Cyl 3.5 L GAS
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Mercury Pressure Switch, Green Part Number: BE8Z-9278-A
$16.03 MSRP: $25.45
You Save: $9.42 (38%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Sending Unit; Switch; Oil Pressure Switch
- Replaces: 1S7Z-9278-AA, SW-6682
Fits the following Mercury Models:
- Mariner | 2005-2008 | Base, Convenience, Hybrid | 4 Cyl 2.3 L FULL HYBRID EV-GAS (FHEV), 4 Cyl 2.3 L GAS
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Mercury Pressure Switch Part Number: G1CZ-9278-B
$24.73 MSRP: $39.27
You Save: $14.54 (38%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Sending Unit; Oil Pressure Switch
- Replaces: 1U5Z-9278-GA, SW-6376, 6U5Z-9278-G, G1CZ-9278-A
Fits the following Mercury Models:
- Mariner | 2009-2011 | Base, Hybrid, Premier | 4 Cyl 2.5 L FULL HYBRID EV-GAS (FHEV), 4 Cyl 2.5 L GAS
- Milan | 2006-2011 | Base, Hybrid, Premier | 4 Cyl 2.3 L GAS, 4 Cyl 2.5 L FULL HYBRID EV-GAS (FHEV), 4 Cyl 2.5 L GAS
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Mercury Oil Pressure Switch Part Number: E4ZZ-9278-A
$21.53 MSRP: $34.18
You Save: $12.65 (38%)
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Product Specifications
- Other Name: Sender Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Oil Pressure Sending Unit
Fits the following Mercury Models:
- Cougar | 1984-1988 | Base, LS, XR-7 | 4 Cyl 2.3 L GAS, 6 Cyl 3.8 L GAS, 8 Cyl 5.0 L GAS
- Marquis | 1984-1986 | Base, Brougham | 4 Cyl 2.3 L GAS, 4 Cyl 2.3 L LPG, 6 Cyl 3.8 L GAS
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Mercury Oil Pressure Sending Unit Part Number: F5RZ-9278-A
$7.94 MSRP: $10.80
You Save: $2.86 (27%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Gauge Sending Unit
Fits the following Mercury Models:
- Mystique | 1995-1999 | Base, GS, GS Spree, LS | 4 Cyl 2.0 L GAS
- Sable | 1996 | G, GS, LS | 6 Cyl 3.0 L GAS
- Tracer | 1998-1999 | GS, LS, Trio | 4 Cyl 2.0 L GAS
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Mercury Pressure Switch Part Number: 6U5Z-9278-M
$102.89 MSRP: $172.73
You Save: $69.84 (41%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Oil Pressure Switch; Oil Pressure Sending Unit; Oil Gauge Sending Unit
- Manufacturer Note: 3/8" NPTF
- Replaces: 1U5Z-9278-BA, 6U5Z-9278-L, SW-6362
Fits the following Mercury Models:
- Cougar | 1999-2002 | Base, S, V6 | 6 Cyl 2.5 L GAS
- Mariner | 2005-2008 | Base, Premier | 6 Cyl 3.0 L GAS
- Montego | 2005-2007 | Luxury, Premier | 6 Cyl 3.0 L GAS
- Sable | 1999-2005 | GS, LS, LS Premium, Platinum Edition | 6 Cyl 3.0 L GAS
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Mercury Pressure Switch Part Number: 6U5Z-9278-A
$126.36 MSRP: $212.73
You Save: $86.37 (41%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Oil Pressure Switch; Oil Pressure Sending Unit; Oil Gauge Sending Unit
- Replaces: 1U5Z-9278-AA, F8AZ-9278-AA
Fits the following Mercury Models:
- Sable | 1999-2005 | GS, LS, LS Premium, Platinum Edition | 6 Cyl 3.0 L GAS
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Mercury Oil Pressure Sending Unit Part Number: F3XY-9278-B
$24.37 MSRP: $33.16
You Save: $8.79 (27%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Light Sw
- Manufacturer Note: #25240,89920
Fits the following Mercury Models:
- Villager | 1993-2002 | Base, Estate, GS, LS, Nautica, Sport | 6 Cyl 3.0 L GAS, 6 Cyl 3.3 L GAS
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Mercury Oil Pressure Sending Unit Part Number: E9BZ-9278-A
$19.43 MSRP: $26.44
You Save: $7.01 (27%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch
Fits the following Mercury Models:
- Tracer | 1991 | LTS | 4 Cyl 1.8 L GAS
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Mercury Oil Pressure Sending Unit Part Number: XS2Z-9278-CA
$2.08 MSRP: $3.31
You Save: $1.23 (38%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch
- Replaced by: XS2Z-9278-AA
Fits the following Mercury Models:
- Mystique | 2000 | GS | 4 Cyl 2.0 L GAS
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Mercury Pressure Switch Part Number: 6U5Z-9278-N
$129.29 MSRP: $212.73
You Save: $83.44 (40%)
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Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Sending Unit; Oil Pressure Switch
- Replaces: SW-6356, 6U5Z-9278-J
Fits the following Mercury Models:
- Mariner | 2008-2011 | Base, Premier | 6 Cyl 3.0 L FLEX, 6 Cyl 3.0 L GAS
- Milan | 2006-2011 | Base, Premier | 6 Cyl 3.0 L FLEX, 6 Cyl 3.0 L GAS
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Mercury Oil Pressure Sending Unit Part Number: D2AZ-9278-AA
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Oil Gauge Sending Unit
Fits the following Mercury Models:
- Cougar | 1999 | V6 | 6 Cyl 2.5 L GAS
- Sable | 1996-1998 | G, GS, LS, LS Premium | 6 Cyl 3.0 L GAS
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Mercury Oil Pressure Sending Unit Part Number: D4AZ-9278-A
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Oil Pressure Switch; Oil Gauge; Oil Gauge Sending Unit
Fits the following Mercury Models:
- Colony Park | 1987-1991 | GS, LS | 8 Cyl 5.0 L GAS
- Cougar | 1984-1997 | Base, LS, XR-7 | 4 Cyl 2.3 L GAS, 6 Cyl 3.8 L GAS, 8 Cyl 4.6 L GAS, 8 Cyl 5.0 L GAS
- Grand Marquis | 1984-1991 | Base, Colony Park, GS, LS | 8 Cyl 5.0 L GAS
- Lynx | 1984-1987 | Base, GL, GS, L, LS, LTS, RS, XR3 | 4 Cyl 1.6 L GAS, 4 Cyl 1.9 L GAS
- Marquis | 1984-1986 | Base, Brougham | 4 Cyl 2.3 L GAS, 4 Cyl 2.3 L LPG, 6 Cyl 3.8 L GAS
- Mountaineer | 1997-1998 | Base | 6 Cyl 4.0 L GAS, 8 Cyl 5.0 L GAS
- Mystique | 1995-2000 | Base, GS, GS Spree, LS, LS Young America | 6 Cyl 2.5 L GAS
- Sable | 1986-1995 | GS, LS, LTS | 4 Cyl 2.5 L GAS, 6 Cyl 3.0 L GAS, 6 Cyl 3.8 L GAS
- Topaz | 1984-1994 | Base, GS, GS AWD, LS, LS AWD, LTS, LTS AWD, Sport, Sport AWD, XR5, XR5 AWD | 4 Cyl 2.3 L GAS, 6 Cyl 3.0 L GAS
- Tracer | 1991-1999 | Base, GS, LS, Trio | 4 Cyl 1.9 L GAS, 4 Cyl 2.0 L GAS
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Mercury Oil Pressure Switch Part Number: E9SZ-9278-A
$12.22 MSRP: $18.91
You Save: $6.69 (36%)
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch; Oil Pressure Gauge Sw; Oil Pressure Sending Unit; Oil Gauge Sending Unit
- Replaces: F4TZ-9278-A
Fits the following Mercury Models:
- Cougar | 1989-1997 | LS, XR-7 | 6 Cyl 3.8 L GAS, 8 Cyl 4.6 L GAS
- Grand Marquis | 1992-1999 | GS, LS | 8 Cyl 4.6 L GAS
- Mountaineer | 1997-1998 | Base | 6 Cyl 4.0 L GAS, 8 Cyl 5.0 L GAS
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Mercury Oil Pressure Sending Unit Part Number: XS2Z-9278-AA
$2.14 MSRP: $3.31
You Save: $1.17 (36%)
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch
- Replaces: XS2Z-9278-CA
Fits the following Mercury Models:
- Cougar | 1999-2002 | Base | 4 Cyl 2.0 L GAS
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Mercury Belt Tensioner Part Number: E9ZZ-9278-A
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Serpentine Belt Drive Kit; Oil Pressure Sending Unit; Serpentine Tensioner
Fits the following Mercury Models:
- Capri | 1985-1986 | 5.0, RS | 8 Cyl 5.0 L GAS
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Mercury Oil Pressure Sending Unit Part Number: 6U5Z-9278-K
Product Specifications
- Other Name: Switch Assembly - Oil Pressure; Engine Oil Pressure Switch
- Replaces: 1U5Z-9278-FA
Fits the following Mercury Models:
- Monterey | 2004-2007 | Base, Convenience, Luxury, Premier | 6 Cyl 4.2 L GAS

Mercury Oil Pressure Switch

If you own Mercury and want to keep it in top shape, choosing OEM Oil Pressure Switch is a smart move. They are precisely engineered and follow strict factory standards. They are made in advanced facilities that use cutting edge technology. Each part goes through thorough testing to confirm strength and safety, so you can trust it. FordPartsDeal.com gives you genuine Mercury Oil Pressure Switch at some of the affordable online prices without cutting quality. Every OEM Mercury part includes the manufacturer's warranty, easy returns, and super-fast delivery. So why wait? Shop now and get your vehicle back to peak condition.

Mercury Oil Pressure Switch is a threaded device, which measures live engine oil pressure and switches the dash light as soon as the readings fall below safe levels. Developed over years of mid-size innovation, Mercury developed its reputation of soft rides, muffled cabins, and light but firm steering. The brand offered a balance between comfort and value whereby families could drive long highways without getting tired but at the same time would have shown a head-turning level of punchy styling that could have been displayed in any parking lot. Fat door seals silence tire noice, wide-spaced seats absorb bumps, and the adjusted suspension makes the body level in speedy points. Thousands of loyal drivers remain attached to Mercury, even after the production was stopped due to the fact that the parts lineup remains durable and easy to service. The Oil Pressure Switch which merely ensures that the engine lasts a mile is one of the unsung heroes in that parts bin. A cool engine will do, whereupon the battery is removed, and then the switch is located next the oil filter, in the majority of the Mercury blocks. Wipe off the area, loosen the exhausted Oil Pressure Switch and anticipate a minor drip. Thread sealant to the new Oil Pressure Switch, screw it by hand, and tighten it with the wrench loosely. Recover the wiring connector until it clicks, connect the battery, and press the engine as you observe the dash. Everything is fine, a constant or darkened metal warning light shows that the Oil Pressure Switch is firmly in place and your Mercury is secure.

Mercury Oil Pressure Switch Parts and Q&A

Pressure Switch
6U5Z-9278-M
Q: How to service the Oil Pressure Switch on Mercury Cougar?
A:
The service process of the oil pressure switch starts with disconnecting the battery ground cable. Raise the vehicle before performing support functions. To operate on the oil pressure switch, you need to disconnect the electric connection then take out the oil pressure switch. Reverse the installation process to service the oil pressure switch unit.
Pressure Switch
G1CZ-9278-B
Q: How to Service the Engine Oil Pressure Switch on Mercury Mariner?
A:
Start the Engine Oil Pressure (EOP) switch service by hoisting the vehicle to a position while keeping it in the neutral gear. The service requires removal of the five bolts and the pin-type retainer and the right-hand splash shield. The service requires removal of the EOP switch electrical connector and thereafter removal of the switch always applying thread sealant to the switch threads before replacement. The EOP switch should be tightened to 15 Nm (133 lb-in) before reconnecting the electrical connector. Reinstall the splash shield by securing its five bolts at 9 Nm torque.