Effect of condensation water on the exhaust system

If condensation hits the hot probe, the ceramic cracks and the probe is broken.

There are several ways to prevent this:

• A protection tube on the probe (has every probe, LSU4.9 has quite different ones), which keeps off water droplets, but still allows gas changes.
• Wait for dew point end, i.e. all water is out of the system. (This can take several minutes for a diesel engine; the probe is not heated until then (=unregulated exhaust gas)).
• Assembly at a place where no/few water droplets are present.