permatex high temp

Riptide

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I just finished putting my o2 defoulers in yesterday. Had to pull the midpipe to get them to thread. I used some permatex high temp red 81160 on the defouler to keep the inserted pill from rattling.

Now I'm reading this may not be safe for my O2 sensors? Would have been nice to know that before hand. There was nothing on that tube saying not for use with O2 sensors. :disgust:

Do I really need to re-do this job? :helpme:
 

slackinoff

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Best way to find out is just wait. If they go wacky.....

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Riptide

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The gasket maker is post combustion and down the line from the wide band sensors. I'm almost sure there is no danger to the car.

It is very close and upstream to the rear narrow band sensors. What I can't find evidence of is whether the poisoning effect occurs only if the sealant is in a location pre-combustion.

Not real happy about this. Already put 50 miles on the car. Permatex is of course closed so I can't call and ask anyone there about it.
 

nyuk98GT

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Riptide,

I am not a sealant guru and I didn't sleep at a Holiday Inn last night and my opinion is 100% free: once the sealant is cured, it is sensor safe regardless of whether or not it was 'sensor safe' as a liquid. So, if the sealant skinned over (and it cures pretty quickly when it is in a thin layer) then the rear O2 sensors should not be at risk.

I looked at the Safety Data Sheets at Permatex for the high-temp sealant (81160) and the sensor safe high-temp sealant (81422). The only significant differences that I saw was a higher vapor pressure for 81160 (10 mm Hg) vs. <5 mm Hg for 81422 and the 81422 lists 'petroleum distillates' as a component. Given the pet distillates in 81422, it is odd that 81422 has a lower v.p. than the 81160. They both have an acetic acid odor.

Not much useful info there but you're on the right path - calling the Permatex gang for the facts. :gr_grin:

Chris
 

Riptide

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Chris thanks. I may wait to speak with them before I do anything else. I'll hold off on driving the car again for now.

Googled a bunch and everything I've found seems to say this is a problem. Permatex will know for sure. If this is an issue a warning on the label would've been nice.
 

RocketcarX

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The issue would be if the sealant blocked the sensors ability to measure air outside the exhaust, like if you had it smeared around the sensor significantly. Some on the threads wouldn't matter
 

Riptide

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From what I've read silicone poisoning happens without needing to physically touch any part of the sensor. It causes some type of glaze to coat the sensor which ruins it. All it has to be is downstream of the RTV.

The situation is confused.

It does say OEM specified on the packaging. And yet they make a whole other part number for "sensor safe". And if you look at the amazon page for the red stuff you can see in the description it states sensor safe properties. But wait. Scroll down on the same page and you can see it says No for sensor safe in the table under the directions.
Amazon.com: Permatex 81160 High-Temp Red RTV Silicone Gasket, 3 oz: Automotive

I am going to have to call them and speak with a tech and hope I get someone who knows what they are talking about.

I don't know how long it takes to poison an O2 sensor. I have read it can happen very quickly. 50 miles on the car already. I wish I knew how to data log the narrow band O2 sensors and verify they are still working.
 

slackinoff

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I see, as the rtv "flashes over" or cures it releases some sticky/nasty chems that can mess up an o2

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RocketcarX

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A basic explanation of how an O2 sensor works is by comparing oxygen content outside the exhaust to the inside of the manifold or pipe it is installed in. The problem is any coating that blocks that ability, it could be mud.
 

Riptide

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Permatex told me I used the wrong stuff and the red is not sensor safe. So I had to re-do the job over again. I used copper sensor safe high temp.

I let it cure outside the car for about 6 hours. It's been inside the pipe now for about 18 hours. Theoretically it should be OK to start the car now. I'm not 100% on that and may let it sit a little longer. Not a lot of air flow inside the pipe.
 

RocketcarX

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Permatex told me I used the wrong stuff and the red is not sensor safe. So I had to re-do the job over again. I used copper sensor safe high temp.

I let it cure outside the car for about 6 hours. It's been inside the pipe now for about 18 hours. Theoretically it should be OK to start the car now. I'm not 100% on that and may let it sit a little longer. Not a lot of air flow inside the pipe.

Why do you insist on putting sealant on it? The only sealant on O2 needs is the miniscule amount of anti-sieze applied when they box them. Thats it.
There is NO sensor safe sealant when you consider what I told you about how the sensor works.
Holy fuck.

On a side note, is it leaking exhaust or something, I mean why are we trying to "seal" anything in the first place?
 
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Wes06

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To keep the pill from rattling.
I can't imagine it's required, or recommended. Seems he just over thinks many things
 

RocketcarX

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So we are taking about tricking the rear O2 sensors into a false reading to let the car live with no cats?
Why not a tune revision for no rear O2 sensors at all...
 

Riptide

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OBD2 emissions state. That would be why. Need monitors to pass.

The pills are known to rattle otherwise. Was recommended to me in another thread.
 

BruceH

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Why do you insist on putting sealant on it? The only sealant on O2 needs is the miniscule amount of anti-sieze applied when they box them. Thats it.
There is NO sensor safe sealant when you consider what I told you about how the sensor works.
Holy fuck.

On a side note, is it leaking exhaust or something, I mean why are we trying to "seal" anything in the first place?

This^^^ The thread design will seal it.

OBD2 emissions state. That would be why. Need monitors to pass.

The pills are known to rattle otherwise. Was recommended to me in another thread.

Put the stock cats back on! For crying out loud they work well. You can always get a set of high flow cats. If you still want to have long tubes then put high flows in the h-pipe and have a tuner who knows that the o2 bias will change with the cats in a different place.

If you are looking at a visual inspection (always needed for an out of state car to be registered in another state) your best bet is the factory exhaust.
 

Riptide

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The permatex doesn't go on the threads. There is confusion about that here. It goes to hold the pill in so it won't rattle. That is it's only purpose in this scenario.

As far as I've read it is only OBD2 in NV that's it. No sniffer or visual.

I don't want cats on the car if I can avoid it. It will be quieter and it is already too quiet IMO. It won't flow as well and I've read enough stories about them coming apart on boosted cars I don't want to take the chance. I know some people have gotten away with it and the stock ones may hold up better than high flows.

Putting the stock cats back on the car is on the laundry list. Just down towards the bottom. As in absolute last thing to try before I have to give up and sell the car if I can't figure this out.
 
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RocketcarX

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The permatex doesn't go on the threads. There is confusion about that here. It goes to hold the pill in so it won't rattle. That is it's only purpose in this scenario.

As far as I've read it is only OBD2 in NV that's it. No sniffer or visual.

I don't want cats on the car if I can avoid it. It will be quieter and it is already too quiet IMO. It won't flow as well and I've read enough stories about them coming apart on boosted cars I don't want to take the chance. I know some people have gotten away with it and the stock ones may hold up better than high flows.

Putting the stock cats back on the car is on the laundry list. Just down towards the bottom. As in absolute last thing to try before I have to give up and sell the car if I can't figure this out.

Every GT500 on the road is blown with cats, surely the boost alone isn't the issue.
Post a pic of the "pill" thing you're talking about, it can't be so large you hear it rattle...can it?
 

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