anti-seize on 02 sensor threads?
 

I'm swapping in a cat bypass. Should I be putting an anti-seize substance on the threads of the O2 sensor or just leave it dry? It came out of the cat real easy and is in great condition.

I brushed a light coat on mine when i swapped a pre muffler 10,000 kms ago. I wiped off the excess with a rag,left just enough to color the threads ...

Not sure if it's a good idea to put too much.

Cheers !
Phil

I think the important thing would be to make sure that the anti-sieze contains no silicone. I think silicone will kill an O2 sensor. Maybe an urban legend...

The copper paste anti-seize seems to work well.

I didn't do this and have paid the price!! My 02 sensor is now a permanent part of my Cat Bypass. So if I want to upgrade my bypass in the future, I can just add the cost of a new sensor to the deal.

Aren't you glad you asked?

I have received some O2 sensors with anti-seize already pre-applied, so it should be OK. Definitely keep it away from the tip though.

Oh yeah I'm glad I asked! Since the PO had recently put the cat back in to get the car smogged for the sale, the sensor and all the bolts came out real easy. But it looks like the sensor could easily get "welded" to the cat. Many thanks to you guys.

I've used the copper anti-sieze without a known issue, I'm very careful to coat mostly the upper threads and don't let anything touch the sensor part. Tip - when taking test pipe in and out put the sensor in a plastic bag and tape it out of the way.

Permatex says their Cu based anti-sieze is rec'd for oxygen sensors, so you should be fine with German brands.

it is silicone that is the big no no

Since 02 sensors are a wear item.....destroying them on removal is no BFD. Cu based paste is best, Si doesn't do the sensor a favor.