Community Member Credit: Frank /

A common problem on the fourth generation (1995-1999) Maxima is a leaking oil pressure switch. Mine has had a slight leak for the last 3 years. The leak was so small that it would never drip, the oil would just “sweat” around the switch. I kept an eye on it at every oil change, or anytime I am under the car to make sure it was not leaking more.

When I was under the car to change my alternator, I noticed that the underside of the car by the oil pressure was slightly wet with oil. It is now time to replace it, before it gets any worse. I went to Car Quest and paid just over $20 for it. (I later found out that it is $12 at Canadian Tire)

It is very easy to install. It is better to replace it when you have removed the oil from the car. (like during an oil change) Otherwise, you need to be quick to remove the old switch, and install the new one to reduce the amount of oil that you loose. (It pours out quite quickly!)

The new oil pressure switch.

The old switch before it was replaced (yellow circle). Notice the oil on the lower control arm. (yellow arrow)

Remove the rubber boot, and gently pull on the connector to remove the wire.

Switch with boot, and connector removed. Notice the oil drip on the bottom of the switch. (yellow arrow)

You will need some thread seal tape, to ensure the new switch does not leak.

Simply wrap it around the threads in the direction OPPOSITE direction of the threads. This will keep the tape from trying to “bunch up” as you tighten it.

Here is the new switch. I used a channel lock to carefully tighten it. You can purchase a special socket for $6 (US) at AutoZone, When I replaced my switch, I did not drain the oil. (it was 3 days oil) With the engine full of oil, you must be quick to remove and replace the switch as the oil pours out quite quickly.

Attach the electrical connector, and push on the rubber boot.

The finished job.

As you can see, this is a simple job. It should not take more than 30 minutes. I would recommend replacing the switch as soon as it leaks, because if it it leaking a little, it could easily leak a lot. In a worst case situation, your could loose all your oil and seize your motor for a $20 part. The $20 is money well spent. (In the US the cost is about $8)


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