How to Service the Oil Pressure Switch on Mercury Cougar?

To service the oil pressure switch, start by disconnecting the battery ground cable. Raise and support the vehicle, then disconnect the electrical connector from the oil pressure switch and remove it. To install, simply reverse the steps taken during removal.

How to Service the Oil Pressure Switch on Mercury Mariner?

To service the oil pressure switch, hoist the vehicle in neutral. Remove the right-hand splash shield bolts (tighten to 9 Nm upon reinstallation). Disconnect the electrical connector and remove the switch, tightening it to 15 Nm during installation. Use Teflon pipe sealant on the switch threads when reinstalling.

OEM Mercury Oil Pressure Switch

Oil Pressure Sender Switch

Select Vehicle by Model
Select Vehicle by VIN

Select Vehicle by Model

Make

Model

Year

Select Vehicle by VIN

For the most accurate results, select vehicle by your VIN (Vehicle Identification Number).

17 Oil Pressure Switches found

View related parts
Mercury Oil Pressure Sensor Part Number: GC3Z-9278-B
$20.37 MSRP: $31.53
You Save: $11.16 (36%)
Ships in 1 Business Day
ADD TO CART
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
View More
View related parts
Mercury Pressure Switch, Green Part Number: BE8Z-9278-A
$2.27 MSRP: $3.60
You Save: $1.33 (37%)
Ships in 1 Business Day
ADD TO CART
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
View related parts
Mercury Pressure Switch Part Number: G1CZ-9278-B
$24.30 MSRP: $38.58
You Save: $14.28 (38%)
Ships in 1 Business Day
ADD TO CART
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
View related parts
Mercury Oil Pressure Sending Unit Part Number: D4AZ-9278-A
$45.08 MSRP: $72.73
You Save: $27.65 (39%)
ADD TO CART
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
View More
View related parts
Mercury Oil Pressure Switch Part Number: E4ZZ-9278-A
$21.07 MSRP: $33.45
You Save: $12.38 (38%)
Ships in 1-2 Business Days
ADD TO CART
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
View related parts
Mercury Oil Pressure Switch Part Number: E9SZ-9278-A
$11.72 MSRP: $18.91
You Save: $7.19 (39%)
ADD TO CART
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
View More
View related parts
Mercury Oil Pressure Sending Unit Part Number: F5RZ-9278-A
$7.94 MSRP: $10.80
You Save: $2.86 (27%)
Ships in 1-2 Business Days
ADD TO CART
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
View More
View related parts
Mercury Oil Pressure Sending Unit Part Number: XS2Z-9278-AA
$2.05 MSRP: $3.31
You Save: $1.26 (39%)
ADD TO CART
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
View related parts
Mercury Pressure Switch Part Number: 6U5Z-9278-M
$102.89 MSRP: $172.73
You Save: $69.84 (41%)
Ships in 1-2 Business Days
ADD TO CART
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
View More
View related parts
Mercury Pressure Switch Part Number: 6U5Z-9278-A
$124.20 MSRP: $209.09
You Save: $84.89 (41%)
Ships in 1-2 Business Days
ADD TO CART
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
View related parts
Mercury Oil Pressure Sending Unit Part Number: F3XY-9278-B
$24.37 MSRP: $33.16
You Save: $8.79 (27%)
ADD TO CART
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
View related parts
Mercury Oil Pressure Sending Unit Part Number: E9BZ-9278-A
$19.43 MSRP: $26.44
You Save: $7.01 (27%)
ADD TO CART
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
View related parts
Mercury Oil Pressure Sending Unit Part Number: XS2Z-9278-CA
$2.08 MSRP: $3.31
You Save: $1.23 (38%)
ADD TO CART
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
View related parts
Mercury Pressure Switch Part Number: 6U5Z-9278-N
$127.08 MSRP: $209.09
You Save: $82.01 (40%)
Ships in 1-2 Business Days
ADD TO CART
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
View related parts
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
View related parts
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
View related parts
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 Parts and Q&A

Oil Pressure Sending Unit
XS2Z-9278-AA
Q: How to Service the Oil Pressure Switch on Mercury Cougar?
A: To service the oil pressure switch, start by disconnecting the battery ground cable. Raise and support the vehicle, then disconnect the electrical connector from the oil pressure switch and remove it. To install, simply reverse the steps taken during removal.
Pressure Switch
6U5Z-9278-M
Q: How to Service the Oil Pressure Switch on Mercury Mariner?
A: To service the oil pressure switch, hoist the vehicle in neutral. Remove the right-hand splash shield bolts (tighten to 9 Nm upon reinstallation). Disconnect the electrical connector and remove the switch, tightening it to 15 Nm during installation. Use Teflon pipe sealant on the switch threads when reinstalling.