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2011 CTSV Coupe M BLK LSX376-B15
1,235 Posts
Discussion Starter · #1 ·
I am writing this post simply as a troubleshooting consideration for those that may be experiencing unaccustomed (unusual) WB behavior pre/post repair.

I first realized an engine performance related issue existed based on unaccustomed 'unusual' WB behavior.

Note: Both OEM primary O2 sensors were not affected at any time before or after repair.

Long story short... I replaced a lifted head gasket, engine is now in perfect operation condition. However, WB readings remained untypical of accustomed behavior?

I thought the WB reading irregularities may have been caused by a PEA engine cleaner fuel additive recently added? However, after contacting both the PEA OEM and AutoMeter, I was assured PEA additives cause no damage to O2 components.

Based on OEM assurance, I hypothesized that the engine cleaner additive may have actually 'optimized' the accuracy of the WB? However, not completely satisfied with this conclusion, I replaced the WB sensor anyway. After sensor replacement, readings are now once again back to accustomed 'normal' operation.

I believe AutoMeter WB O2 sensors are susceptible to permanent damage when contaminated by engine coolant. In my case, the WB sensor was not exposed to a significant volume of coolant for an extended period of time, so it may not take very much for very long.

In conclusion:
if engine symptoms exist that 'typically' indicate manifold/vacuum/exhaust leaks, and WB readings are not typical, don't overlook the possibility of coolant burning in the engine. In addition, some O2s can be sensitive to damage from coolant exposure, even if only for a short period of time as in my experience.

In my case there was never white exhaust, an extreme loss of coolant, or bubbling in the coolant reservoir. So it appears that even small coolant leaks can be hard to accurately detect when troubleshooting. The only indicator I had leading to the possibility of an engine coolant leak, other than 'sputtering' and lower performance, was a clean upper side intake valve. (see attached image)

I hope this information is useful, any feedback is appreciated.

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