I’ve just discovered that using high volatility silicone sealant not labeled as “oxygen sensor safe” on valve cover gaskets could contaminate and ruin the oxygen sensors. However, I just used a few small dabs around certain areas, not all the way around the cover, with some of the sealant having sq…

Seriously? A heck of a lot of engines have PCV valves right in the valve cover. If you lay a bead of RTV on the cover you can bet those vapors are going to be ingested and burned. The oil returns all go to the crankcase too. Even the manufacturers cite the risk but you don’t believe it? It’s one thi…

Urban legend BS. If RTV was an O2 killer then this should mean that many GM cars would have wiped their O2s right after rolling off of the assembly line. Some may remember that GM did not even use valve cover gaskets; they used an overhead gun to run a bead of silicone only on the cylinder heads. W…

RIF. RTV is an acronym for Room Temperature Valcanizing. There are many formulations of RTV sealants. It’s a certain TYPE of SILICONE RTV that affects the sensor and I’m pretty sure the GM engineers know which type to specify. Also, the GM stuff is designed to cure very fast to speed up repair time…

Like Twin Turbo says, there are different formulations. It appears to be the high volatility stuff with the acetic acid smell that’s bad, and can release fumes that get sucked in by the PCV valve. Sealant labeled “Oxygen sensor safe” are apparently low volatility and don’t give off as much of the …

The highest temperature RTV I’ve ever seen is rated to maximum temperatures of 650F, I don’t believe any silicone silastic can withstand the temperatures of combustion chambers, which can exceed 2000F. I agree with those that say it’s a myth. I don’t see any way that fumes from curing silicone RTV …

I was also skeptical at first, but searching the Net convinced me that there is something to it. GM discovered it. Even Bosch, which makes these sensors, warns about it. From what I’ve read, these things work on a molecular level, so since I don’t have a good understanding of chemistry, etc. etc.…

There’s a big difference between what I don’t understand and what’s correct. I’d follow Bosch’s instructions, too. Great user name, by the way.

The exhaust gas volume is so large, the amount of silicone “vapor” is so small…It’s not like you were squirting the silicone right into the intake manifold of a running engine…What little “vapor” there is, most of that tiny fraction will be absorbed by and dissolved in the motor oil and held there u…

I don’t buy into silicone sealer killing O2 sensors for one second. As I mentioned, by the time someone is gooping up oil pans, valve covers (possibly in tandem with a head gasket), and so on that tells me someone is dealing with a high miles or problematic engine. Any O2 problem is likely related t…

How much silicone sealant will ruin the oxygen sensors?

Maintenance/Repairs

texases January 11, 2012, 11:59pm 13

I also can’t understand what vapors would come off curing RTV that could survive a trip through the combustion chamber. In addition to being burned up, it would be diluted by a million to one (or more). I’m pretty sure any acetic acid fumes would be consumed.

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How much silicone sealant will ruin the oxygen sensors?

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