How to Remove and Replace Passenger Side Oxygen Sensor 1994 Corvette C4 LT1
#1
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How to Remove and Replace Passenger Side Oxygen Sensor 1994 Corvette C4 LT1
Here is my method for removing that pesky pre-catalytic, passenger side oxygen sensor on my corvette. I hope this will make it easier for anyone trying this for the first time, as I became really discouraged at first and left the sensor on for much longer than it should have been.
What I used:
Oxygen sensors
Rental Oxygen Sensor Wrench Set
Long ratchet extensions (or several small ones)
3/8'' ratchet (3/8" breaker bar to get it loose)
PB Blaster
First I go to Advance Auto Parts and rent this Oxygen Sensor Wrench Set and buy the oxygen sensors.
What I used:
Oxygen sensors
Rental Oxygen Sensor Wrench Set
Long ratchet extensions (or several small ones)
3/8'' ratchet (3/8" breaker bar to get it loose)
PB Blaster
First I go to Advance Auto Parts and rent this Oxygen Sensor Wrench Set and buy the oxygen sensors.
Last edited by 94c4seminole; 05-30-2015 at 06:18 PM.
#2
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Thread Starter
When you have all the tools you need, put the front of the car up on jack stands or ramps and spray PB Blaster where the oxygen sensors bolt into the exhaust. This is especially helpful if the sensors have been on for a long time.
Once the exhaust is cool enough to work with, you can remove the Driver's side sensor easily from under the car with the long socket (middle one pictured above). Unplug the wiring first and make sure the connector is clean for the new one. There isn't a lot of room to ratchet loose the sensor so it takes a while, but it is straightforward. Make sure the wiring sits in a way that it does not touch the hot exhaust or engine block.
Now for the passenger side... It was really impossible for me to get a socket and ratchet on this one from underneath. Put the smallest socket from the set on the sensor while you are underneath the car with the ratchet hole facing the passenger door. You can see this in the second picture below, the manifold is above and you are looking down from right front of the car.
From above the car, take a ratchet or breaker bar (depending on how stuck the sensor is) with all the extensions on it and direct it down past the manifold into the socket. It is helpful to have extensions like mine that allow some play when they are halfway on. The have curved ends rather than square.
Once the exhaust is cool enough to work with, you can remove the Driver's side sensor easily from under the car with the long socket (middle one pictured above). Unplug the wiring first and make sure the connector is clean for the new one. There isn't a lot of room to ratchet loose the sensor so it takes a while, but it is straightforward. Make sure the wiring sits in a way that it does not touch the hot exhaust or engine block.
Now for the passenger side... It was really impossible for me to get a socket and ratchet on this one from underneath. Put the smallest socket from the set on the sensor while you are underneath the car with the ratchet hole facing the passenger door. You can see this in the second picture below, the manifold is above and you are looking down from right front of the car.
From above the car, take a ratchet or breaker bar (depending on how stuck the sensor is) with all the extensions on it and direct it down past the manifold into the socket. It is helpful to have extensions like mine that allow some play when they are halfway on. The have curved ends rather than square.
Last edited by 94c4seminole; 05-30-2015 at 06:23 PM.
#3
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Thread Starter
Try to get it as straight up and down as possible and use the breaker bar if necessary to get it loose. Once it breaks free, you can keep turning the socket in small increments from above by lifting up the whole ratchet/extension/socket setup and placing it back down for another turn. Once it is loose enough, you can go back under the car and loosen the rest by hand.
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LouisvilleLT4 (09-13-2015)
#4
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Thread Starter
Tighten it on by hand as much as you can. Then do the rest from above just like you loosened it. I just get it snug, not too tight. You will be careful to do this too if it was a real struggle to remove in the first place! I'm no professional, but this sure helped me out. I learn more about this car every day.
Hope this helps, -Evan
P.s. for those who are more knowledgeable than me, please submit any ways to do this better!
Hope this helps, -Evan
P.s. for those who are more knowledgeable than me, please submit any ways to do this better!
Last edited by 94c4seminole; 05-30-2015 at 06:25 PM.
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94c4seminole (10-09-2015)
#7
Safety Car
I use the big O2 sensor socket with the relief so you don't pinch the wire. I do have several 12 inch extensions as well as a 24. So put the 24 on the socket and add a 12 inch. You can get the socket on the sensor from above although it is a bit tight. Make sure you get the socket all the way down on the sensor flats. Then untighten it about 1/2 turn. If you have used the OEM sensors with the graphite impregnated grease, that was enough for me to then get under the car and undo it from the bottom with my fingers. Don't use that socket to do more than 1/2 to 3/4 of a turn without unplugging the wire however. Then simply start the new sensor and I was able to get it within 1/2 a turn of the 30 ftlb torque spec from the bottom with my fingers. Than tighten from the top with the final 1/4 turn with a torque wrench on it and then back under to connect the wire. I have a lift so that underneath stuff is much easier.
The first time I installed a right side I neglected to torque it and what I thought was tight wasn't and I had enough of a leak that I failed my first smog test. After the retorque, no problem.
Now the hard part over their is replacing that cat and downpipe. Again driver side is easy but passenger side is not. Did that several years ago, when a blown engine totalled the passenger side cat.
Good Article. A lot of the secret is the more appropriate tools you own the better. I don't think the deep Sensor socket was much more than 6-7$ and I have used it a good number of times.
BTW, mine is a 93 which has a 1 wire sensor. I think the 94 has a 3 wire doesn't it? Less to get in the way of the deep socket with a 1 wire.
The first time I installed a right side I neglected to torque it and what I thought was tight wasn't and I had enough of a leak that I failed my first smog test. After the retorque, no problem.
Now the hard part over their is replacing that cat and downpipe. Again driver side is easy but passenger side is not. Did that several years ago, when a blown engine totalled the passenger side cat.
Good Article. A lot of the secret is the more appropriate tools you own the better. I don't think the deep Sensor socket was much more than 6-7$ and I have used it a good number of times.
BTW, mine is a 93 which has a 1 wire sensor. I think the 94 has a 3 wire doesn't it? Less to get in the way of the deep socket with a 1 wire.
Last edited by pkincy; 05-30-2015 at 08:13 PM.
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94c4seminole (10-09-2015)
#8
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Thread Starter
I use the big O2 sensor socket with the relief so you don't pinch the wire. I do have several 12 inch extensions as well as a 24. So put the 24 on the socket and add a 12 inch. You can get the socket on the sensor from above although it is a bit tight. Make sure you get the socket all the way down on the sensor flats. Then untighten it about 1/2 turn. If you have used the OEM sensors with the graphite impregnated grease, that was enough for me to then get under the car and undo it from the bottom with my fingers. Don't use that socket to do more than 1/2 to 3/4 of a turn without unplugging the wire however. Then simply start the new sensor and I was able to get it within 1/2 a turn of the 30 ftlb torque spec from the bottom with my fingers. Than tighten from the top with the final 1/4 turn with a torque wrench on it and then back under to connect the wire. I have a lift so that underneath stuff is much easier.
The first time I installed a right side I neglected to torque it and what I thought was tight wasn't and I had enough of a leak that I failed my first smog test. After the retorque, no problem.
Now the hard part over their is replacing that cat and downpipe. Again driver side is easy but passenger side is not. Did that several years ago, when a blown engine totalled the passenger side cat.
Good Article. A lot of the secret is the more appropriate tools you own the better. I don't think the deep Sensor socket was much more than 6-7$ and I have used it a good number of times.
BTW, mine is a 93 which has a 1 wire sensor. I think the 94 has a 3 wire doesn't it? Less to get in the way of the deep socket with a 1 wire.
The first time I installed a right side I neglected to torque it and what I thought was tight wasn't and I had enough of a leak that I failed my first smog test. After the retorque, no problem.
Now the hard part over their is replacing that cat and downpipe. Again driver side is easy but passenger side is not. Did that several years ago, when a blown engine totalled the passenger side cat.
Good Article. A lot of the secret is the more appropriate tools you own the better. I don't think the deep Sensor socket was much more than 6-7$ and I have used it a good number of times.
BTW, mine is a 93 which has a 1 wire sensor. I think the 94 has a 3 wire doesn't it? Less to get in the way of the deep socket with a 1 wire.
#12
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#13
Safety Car
Source: http://tech.corvettecentral.com/2007...oxygen-sensor/
#14
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Thread Starter
"you can use a box end wrench and just thread the wires through the box end."
Source: http://tech.corvettecentral.com/2007...oxygen-sensor/
Source: http://tech.corvettecentral.com/2007...oxygen-sensor/
#15
#16
Safety Car
Different sensors have their flats in different places. I agree some sensors have their flats high enough on the sensor to be easier to remove in each case. I find the Delco AFS21 to not have that characteristic. The only way a box end would get to my passenger side would be if it had two 45 degree angles built in....one 1/2 inch from the box end and the other 2-3 inches from that bend. Now had I not been able to get at it from the top I was ready to sacrifice a 7/8ths to the torch to make that extra tool.
#17
Racer
I must have moved O2 sensors left to right and right to left...seems like a hundred times hunting down things. That's Bosch, AC Delco, and NGK..they're all the same wrench.
You guys are FULL OF ****.
Never EVER used anything but a hand wrench, at the base.
I'm really not sure what anyone is supposed to learn from this.
You guys are FULL OF ****.
Never EVER used anything but a hand wrench, at the base.
I'm really not sure what anyone is supposed to learn from this.
Last edited by Drew95; 06-05-2015 at 01:11 AM.
#18
Safety Car
I must have moved O2 sensors left to right and right to left...seems like a hundred times hunting down things. That's Bosch, AC Delco, and NGK..they're all the same wrench.
You guys are FULL OF ****.
Never EVER used anything but a hand wrench, at the base.
I'm really not sure what anyone is supposed to learn from this.
You guys are FULL OF ****.
Never EVER used anything but a hand wrench, at the base.
I'm really not sure what anyone is supposed to learn from this.
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SloJo (11-28-2020)
#19
Racer
Actually, it was the opposite of being smart that lead to the advice, but whatever. Just offering .02... do what you want.