I’ve been working on my o2 sensors and since they’re expensive I tried to clean them before replacing on the off chance they will still work. I cleaned them with degreaser, and I cleaned the passenger downstream one with water. I don’t think this would be a big deal since I let them dry. After replacing all the sensors in the correct spots, I started the truck(cold) and immediately clouds of white smoke came out. I have a horrible sense of smell so I can’t tell what it’s burning exactly, but I let the truck warm up to open the thermostat and let it run for a bit. After turning it off the coolant level didn’t change. Is there an issue in the computer causing the mixture to be rich or should I look elsewhere?

it also might be relevant to say I changed the head gasket about 1000 miles or so ago.

 

What were you troubleshooting when you removed and cleaned the sensors? And did the white smoke clear out once it warmed up? What about later cold start cycles? My money would be on them burning off whatever got on them, but that wouldn't hold water if it didn't clear pretty quickly and/or returns every time you start it. If that's the only thing you did prior to the smoke, I wouldn't worry too much about the head gasket. WHite smoke doesn't sound like running rich.

I'm sure smarter people than me will respond.

 

I was troubleshooting codes for the sensors so I can pass state inspection, I started it again shortly after and there was less smoke but still a lot. In my opinion there is way too much smoke for it to be from the cleaner since I wiped most of it off

 

Started it today and there was a little smoke but it’s cold out, drive it and it ran fine didn’t lose any coolant. Problem seems to have gone away.

 

I have heard soaking an o2 sensor in seafoam over night is an effective way to clean but cleaning is not always the problem as they age the electronic signal strength gets weaker and sends error codes to ecu

 

Look for NTK 25044 oxygen sensors. Rockauto has them. Amazon seems to have discontinued them. eBay is another option. Replace just the upstreams. Should be less than $65 each