Mercury Monarch Oxygen Sensor Replacement at your home or office.

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Oxygen Sensor Replacement Service

How much does a Oxygen Sensor Replacement cost?

On average, the cost for a Mercury Monarch Oxygen Sensor Replacement is $185 with $90 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1977 Mercury MonarchL6-4.1LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementEstimate$295.39Shop/Dealer Price$350.49 - $493.29
1978 Mercury MonarchV8-5.0LService typeOxygen Sensor - Front/Upper/Upstream ReplacementEstimate$279.23Shop/Dealer Price$335.31 - $481.00
1975 Mercury MonarchL6-4.1LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementEstimate$275.39Shop/Dealer Price$330.51 - $473.32
1980 Mercury MonarchV8-4.2LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementEstimate$275.39Shop/Dealer Price$330.49 - $473.28
1978 Mercury MonarchV8-5.0LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementEstimate$275.39Shop/Dealer Price$330.52 - $473.35
1979 Mercury MonarchV8-5.0LService typeOxygen Sensor - Front/Upper/Upstream ReplacementEstimate$279.23Shop/Dealer Price$335.31 - $481.00
1976 Mercury MonarchV8-5.0LService typeOxygen Sensor - Rear/Lower/Downstream ReplacementEstimate$280.39Shop/Dealer Price$335.37 - $478.08
1976 Mercury MonarchV8-5.0LService typeOxygen Sensor - Front/Upper/Upstream ReplacementEstimate$284.23Shop/Dealer Price$340.54 - $486.42
Show example Mercury Monarch Oxygen Sensor Replacement prices

What is the Oxygen Sensor all about?

With each new model year, manufacturers are adding more oxygen sensors to better manage engine operation. Some high performance engines have an oxygen sensor for each cylinder as well as one for the rear of each catalytic convertor. The sensors are located either underneath the hood or underneath the car. The oxygen sensors are connected (screwed) to the exhaust pipe, either in front or back of the catalytic converter. The front (upstream) sensors measure the amount of oxygen in the exhaust system. The purpose of the front oxygen sensor(s) is to measure how rich or lean the gases are as the gases exit the combustion chamber. Depending upon whether the exhaust gas is lean (high in oxygen content) or rich (low in oxygen content), the amount of fuel entering the engine is adjusted by the engine management computer to try and maintain an ideal mixture that produces the lowest emissions output from the catalytic convertor.

Rear (downstream) sensors are located behind the catalytic converter. The purpose of the rear oxygen sensor(s) is to monitor the oxygen content of the exhaust gases leaving the catalytic convertor.

If one or more of the oxygen sensors are faulty, your car may not pass the emissions test. If you drive your car with a faulty oxygen sensor, you may get poor gas mileage and it can damage the catalytic converter.

Oxygen Sensor-MATROX-1

When replacing the oxygen sensor remember:

  • Many oxygen sensors are damaged by leaking oil or coolant. If that is the case, the cause of that leak needs to be identified and repaired, or else the replacement oxygen sensor will be damaged as well.
  • New vehicles require specific oxygen sensors, and not the universal sensors that were common prior to 1996.

How it's done:

  • Scan the computer in the car for codes.
  • Inspect for vacuum leaks and holes in the exhaust system.
  • Remove and replace the oxygen sensor if it is bad.
  • Check electrical connections.
  • Check for proper operation of oxygen sensors.
  • Clear diagnostic codes.
  • Test drive car.

Our recommendation:

Keep up with the tune-ups. If check engine light is on, don't drive the car too long without getting it inspected. If check engine light is flashing, pull over and get the car towed to avoid costly repairs. Ask the mechanic to inspect the vacuum hoses and leaks in the exhaust system. If the vacuum hose or exhaust system is leaking, it will display an oxygen sensor fault code. Replacing an oxygen sensor may not fix the problem.

What common symptoms indicate you may need to replace the Oxygen Sensor?

  • Check Engine light is on.
  • Car is getting poor gas mileage.
  • Emission test fails.

How important is replacing the oxygen sensor?

Your vehicle has multiple oxygen sensors, and they all help the car run optimally. The front sensors measure how much oxygen is in the exhaust stream to measure how rich or lean the gases leaving the gas chamber are. The rear sensors measure the oxygen content of the gases as they leave the catalytic converter. The oxygen sensors then relay this information to your vehicle’s electronic control unit, so that it can adjust as necessary. Because cars depend on an ideal fuel-to-air ratio to function optimally, the oxygen sensors are leaned on for engine performance. When your oxygen sensors fail your car will run less smoothly, get worse mileage, and have worse emissions.

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Meet some of our expert Mercury mechanics

Real customer reviews from Mercury owners like you.

Excellent Rating

(9)

Rating Summary
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Michael

16 years of experience
606 reviews
Michael
16 years of experience
Mercury Grand Marquis V8-4.6L - Oxygen Sensor Replacement (Front/Upper/Upstream, Rear/Lower/Downstream) - Atlanta, Georgia
Helped a lot. Fixed 8 of 10 problems with my car

David

13 years of experience
393 reviews
David
13 years of experience
Mercury Mountaineer V6-4.0L - Oxygen Sensor Replacement (Front/Upper/Upstream) - Marietta, Georgia
David was very thorough and explained everything to me. Will be using him again in the future.

Victor

11 years of experience
211 reviews
Victor
11 years of experience
Mercury Mountaineer V6-4.0L - Oxygen Sensor Replacement (Front/Upper/Upstream) - Virginia Beach, Virginia
Victor is always on time, with parts and everything he needs to put them on your vehicle. Victor is always prepared, he put wheel bearings and ball joints the other day on my SUV and I drove to Baltimore from Virginia beach yesterday with not a care on my mind whether he did his job right or not, my truck drove so smoothly. Today was EGR valve and of course he was prepared and it only took him an half hour, because he doesn't play around. He enjoys what he does and knows what he's doing. Victor explains what the part is and how it's needed on your vehicle. He explains everything. I feel so comfortable knowing he's the one coming to work on my vehicle for so many reasons, and one is I know it will be done right! That's my biggest worry when it comes to someone working on my vehicle. So, you can have your part or not, Victor will come to you..ON TIME.., GREAT PRICES.., PROFESSIONAL ATTITUDE.., SO NICE.., I'M JUST TRYING TO SAY EVERYTHING IS THE BEST AND IT WOULD DO YOU A GREAT SERVICE TO JUST TRY MR. MECHANIC 1 TIME, YOU'LL BE GLAD YOU DID AND YOU'LL BE LIKE ME AND KEEP THEM FOR LIFE! VICTOR IS NOW MY LIFETIME MECHANIC !! THANK YOU A.DAYE

Henry

34 years of experience
170 reviews
Henry
34 years of experience
Mercury Sable V6-3.0L - Oxygen Sensor Replacement (Front/Upper/Upstream, Rear/Lower/Downstream) - Sicklerville, New Jersey
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Excellent Rating

(9)

Rating Summary
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Number of Mercury Oxygen Sensor Replacement services completed
99+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercury MECHANICS
600+
experts on our platform

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