Oxygen Sensor Wrench

[Dean P]

Picked up 2 oxygen sensors; yes. Went to install; no. Purchased an oxygen sensor wrench; yes. Went to remove oxygen sensor; no. The outside diameter of the wrench won't fit into the c'bore hole to get at the hex nut on the oxygen. Damn! Do anybody know which wrench fits or should I try to grind the OD to accommodate? Damn, damn!

 

[the MfM]

Picked up 2 oxygen sensors; yes. Went to install; no. Purchased an oxygen sensor wrench; yes. Went to remove oxygen sensor; no. The outside diameter of the wrench won't fit into the c'bore hole to get at the hex nut on the oxygen. Damn! Do anybody know which wrench fits or should I try to grind the OD to accommodate? Damn, damn!

View attachment 89950

What’s the outside diameter of your socket?

I just checked my set and I have three 22mm sockets. The short offset has the biggest O.D. The mid length offset is turned down a good 1/16” and the deep one is a slightly smaller than that.




To get the old ones out could you cut the wires and use a chrome socket?

 

[Dean P]

What’s the outside diameter of your socket?

I just checked my set and I have three 22mm sockets. The short offset has the biggest O.D. The mid length offset is turned down a good 1/16” and the deep one is a slightly smaller than that.

I'll have to check. I meant to bring it into work but forgot. I almost went for the deep socket type too. Too cheap for my own good. Damn!

 

[the MfM]

An auto parts store like advance or VIP should have free rental sets available.

 

[Marvin willis]

Use a reg n wrench. I never saw the point in buying the socket

 

[Dean P]

Use a reg n wrench. I never saw the point in buying the socket

Was the first thing I tried. Couldn't get it to bite. I just ground down the OD to 1.240. It should fit.

 

[swatski]

Picked up 2 oxygen sensors; yes. Went to install; no. Purchased an oxygen sensor wrench; yes. Went to remove oxygen sensor; no. The outside diameter of the wrench won't fit into the c'bore hole to get at the hex nut on the oxygen. Damn! Do anybody know which wrench fits or should I try to grind the OD to accommodate? Damn, damn!

View attachment 89950

Check with @Ron@Scarab he will know for sure.

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[Dean P]

Check with @Ron@Scarab he will know for sure.

Thank you for the tip. I ground down the OD to the wrench I purchased. I'll post back to let everyone know if it worked.

 

[Dean P]

Turned down the wrench to 1.240 and it worked. Was able to remove the sensors with no issues. I removed them and took pictures of each one. How bad are these? Appears to be sand on them? Not sure what to look for here. Should I toss them or just clean them?

 

[2kwik4u]

That "sand" looks like exhaust gas deposits on a less than ideal temp sensor. Probably the result of water cooled manifolds. However I'm speaking from automotive knowledge, not marine knowledge. Hopefully others will know more than I. I'm curious.

 

[Sbrown]

It could also be anti-seize residue if the last guy who had them out used the wrong stuff. I see some of the same substance up under the sealing washer is why I suggest that.

 

[Dean P]

It could also be anti-seize residue if the last guy who had them out used the wrong stuff. I see some of the same substance up under the sealing washer is why I suggest that.

I have 2 new ones to install and there's anti-seize lube on the threads. Not sure how that would get inside the chamber. Could it be sand??? Why would it not flush away?

 

[Sbrown]

I have 2 new ones to install and there's anti-seize lube on the threads. Not sure how that would get inside the chamber. Could it be sand??? Why would it not flush away?

I didn't say using anti-seize was wrong, but there are different compositions of anti-seize and some have different properties than others. Its possible somebody had those out already and maybe used the wrong kind of anti-seize when they were reinstalled. The way it gets into the chamber is when the exhaust heats up, the wrong anti-seize will melt and run down the threads and get all over the exposed sensor portion. It will also get inside the sensor and contaminate it. I'm not saying thats definitely what happened here, I'm just calling out the possibility.

 

[Dean P]

I didn't say using anti-seize was wrong, but there are different compositions of anti-seize and some have different properties than others. Its possible somebody had those out already and maybe used the wrong kind of anti-seize when they were reinstalled. The way it gets into the chamber is when the exhaust heats up, the wrong anti-seize will melt and run down the threads and get all over the exposed sensor portion. It will also get inside the sensor and contaminate it. I'm not saying thats definitely what happened here, I'm just calling out the possibility.

Oh, ok. That makes sense. Thx, I did not know that.

Could this be crystallized salt? I only boat in salt water but flush after every use.

 

[Sbrown]

Oh, ok. That makes sense. Thx, I did not know that.

Could this be crystallized salt? I only boat in salt water but flush after every use.

I don't think so. The sensors shouldn't be in a position to get water on them at all.

 

[swatski]

I don't think so. The sensors shouldn't be in a position to get water on them at all.

I could be totally wrong but the Yamies mix water with exhaust up past waterboxes, don't they?
(That's a @buckbuck question!).
We know that BRP powerplants have similar raw water exhaust cooling, right?

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[Dean P]

I don't think so. The sensors shouldn't be in a position to get water on them at all.

I could be totally wrong but the Yamies mix water with exhaust up past waterboxes, don't they?
(That's a @buckbuck question!).
We know that BRP powerplants have similar raw water exhaust cooling, right?

Actually, they do get wet. It is where the exhaust mixes with the water. So, could it just be salt?

 

[Sbrown]

I understand how the cooling systems work and the wet flow exhaust. I'm still pretty sure the o2 sensors don't get wet. They wouldn't work correctly in a wet environment. Water is considered a contaminant. So if you're getting water on your o2 sensor, then yes that is what is causing them to fail. Water is introduced to the actual exhaust stream well downstream of the oxygen sensors. Yes, the manifolds are water cooled, but the water flows through a separate jacket than the exhaust. Basically there's two internal passages in the manifolds, one for exhaust gas and a separate one for water. Now, a internal crack that allows water to get introduced to the exhaust flow prematurely that allows raw water to contact your sensors could very well cause your sensor failure.

 

[Dean P]

I understand how the cooling systems work and the wet flow exhaust. I'm still pretty sure the o2 sensors don't get wet. They wouldn't work correctly in a wet environment. Water is considered a contaminant. So if you're getting water on your o2 sensor, then yes that is what is causing them to fail. Water is introduced to the actual exhaust stream well downstream of the oxygen sensors. Yes, the manifolds are water cooled, but the water flows through a separate jacket than the exhaust. Basically there's two internal passages in the manifolds, one for exhaust gas and a separate one for water. Now, a internal crack that allows water to get introduced to the exhaust flow prematurely that allows raw water to contact your sensors could very well cause your sensor failure.

I meant to say, they could get wet. See the picture below. If I understand this correctly, the oxygen sensor sits just above the "Y" where the exhaust and water meet. Is is possible for spray back? Without actually tasting it , could it be salt?

 

[Sbrown]

I meant to say, they could get wet. See the picture below. If I understand this correctly, the oxygen sensor sits just above the "Y" where the exhaust and water meet. Is is possible for spray back? Without actually tasting it , could it be salt?

View attachment 90045

Anything is possible, of course. But I think that, unless you have some sort of restriction in your exhaust system downstream of that junction, sprayback is unlikely. I really don't think that's salt on the sensor.