1997 O2 sensor replacement, what type sealer?

[Recoil Rob]

The "check engine" light has been on for some time, my inspection station put the the diagnostic tester on it and tells me the down stream O2 sensor is bad.

This is the sensor that's just ahead of the catalytic converter, mounted on a diamond shaped flange that's held onto the hole by 2 nuts on studs on the manifold end.

The hard part is done, I got the exhaust nice and hot, sprayed the two studs and nuts with Kroil, and was able to take the old one out with a minimum of swearing, took about 20 minutes.


I noticed that there is a rubbery sealant that was used when it was originally installed, what do I use to seal the new one?


thanks,

Rob

 

[T4R2014]

It doesn't need sealant. Just use the gasket it comes with.

 

[Recoil Rob]

OK, gotta back up for a minute, while just looking for the parts online I realize I took out the one ahead of the CC, didn't even see the one after it which is the downstream one.

That one just came out real easy as the studs were rusted to the nuts and there were no threads left. There was plenty of room to use a long 1/2' swivel headed ratchet and the studs just broke off but left enough to situate the new sensor so it won't slide around.

I'm thinking I'll use some kind of sealant and just strap it on with stainless steel band clamps.

Any suggestions as to high heat sealant? Silicone is supposed to be good up into the 400˚ range, will this work?

Also, who has the best price on this stuff?


thanks,

Rob

 

[BlackCat914]

OK, gotta back up for a minute, while just looking for the parts online I realize I took out the one ahead of the CC, didn't even see the one after it which is the downstream one.

That one just came out real easy as the studs were rusted to the nuts and there were no threads left. There was plenty of room to use a long 1/2' swivel headed ratchet and the studs just broke off but left enough to situate the new sensor so it won't slide around.

I'm thinking I'll use some kind of sealant and just strap it on with stainless steel band clamps.

Any suggestions as to high heat sealant? Silicone is supposed to be good up into the 400˚ range, will this work?

Also, who has the best price on this stuff?


thanks,

Rob

Don't use any sealant.

 

[Recoil Rob]

OK, but what's the problem with a high temp sealant? I want to use it because there's' only enough of the studs left to locate the flange. If I use the gasket under it the sensor will not be on the studs.

Honestly, going for the quick fix here to get it inspected.

 

[T4R2014]

Sounds like you need a new exhaust.

 

[Recoil Rob]

Rest of the exhaust is fine, will use gaskets, just want to know why hi temp sealant is a bad idea...

 

[Recoil Rob]

Did some snooping and as it turns out some sealer will give off a gas that can ruin a downstream sensor. This is what probably ruined the downstream sensor to begin with as I found sealant instead of a gasket when I mistakenly removed the upstream sensor.

Although Permatex says their RTV # 80022 is Sensor Safe....

 

[Recoil Rob]

Turns out Permatex 80022 is not O2 sensor safe, only the high temp copper is.