2T oil doesn't ruin O2 sensors far from it.Most cars have heated 4 wire lambda probes that basicaly burn any oil off. If lambda probes were ruined by oil there wouldn't be a Mitsubishi running........................
I must be in the wrong trade for the last 30 years...straight from Bosch's site
Exposure to carbon, soot, harmful gases, anti-freeze, chemicals plus thermal and physical shock will shorten the life of an Oxygen Sensor. This results in increased fuel consumption, poor engine performance and excessive exhaust emissions.
From Performance Trends.......
The A/F sensors can even be used on 2 stroke engines, as shown below in the graph of results from an 85 cc 2 stroke. The data was obtained with remote sampler fitted with a special trap for the oil aerosol developed by the dyno operator. The dyno operator says the A/F data is very valuable to track changes in tuning which has a large impact on the 2 strokes power output. Note also how the head temperature gets warmer as the A/F gets leaner. We will soon be able to fit an aerosol trap to our DT2-AFR Remote Sampling System for 2 stroke engines. (Due to the high oil consumption of 2 strokes, sensor life is reduced and some systems do not recommend use with 2 strokes. We are still investigating the accuracy on 2 strokes and the expected life of the sensors.)
Early cars aren't heated and i used to throw my left over kart fuel into my VN...trust me....it does what it says above.
Cars don't stop running with knackered O2's including the oil burning "bitsamissing" they just don't send the correct signal to the ECU/M anymore.
I'm dealing with Cats and O2's everyday in the emissions lab at work....but this thread is about R30
so i'll shut up now