Multiple O2 sensor failure

After receiving service at my local dealership my valve cover was severely leaking oil. 3 quarts in 3 days… So, oil was leaking everywhere and was potentially being burned as well. 2 O2 sensors failed after the oil leak started but before they fixed it. Of course, they say it is unrelated. I have received conflicting opinions so far. what does the group say? Thanks in advance for your help!

what was the original service for?
where was the valve cover leaking?
are you sure the oil cap was not left off?
Did you not smell the oil burning on the exhaust right away?
A valve cover gasket does not usually just blow out that bad for you to use that much oil so quickly. it usually starts as a smaller leak.
the oil leaking probably blew back to the O2 sensor connections, got inside and caused the O2 sensor failures.
You can always try going up the chain to the corporate office for help. the number is in your owner’s manual.

Coolant leaking into any of the cylinders will kill O2 sensors in a short time.


You need to provide more info.
Mileage on the vehicle, what was the service(s) provided when you took it in, and so on. It’s near impossible to make even a wild guess on this one.

A valve cover would have to have a pretty serious issue to spit up3 quarts of oil in 2 days so was the valve cover removed for any reason during the service you took it in for?

The original service was failed water pump, the timing chain was also replaced. The valve cover was leaking that bad because they forgot to torque it. I didn’t notice it the 1st day and noticed it the second, and took it back to the dealership the 3rd day.

Some types of O2 sensors require a fine-mesh path from the inside of the sensor to outside air. If oil leaked onto that mesh, it could damage the sensor. Don’t know if this applies to your car’s O2 sensors though. You might do a little research via Google on how common types of O2 sensors work; e.g. Google how does lambda O2 sensor work?

Still missing relevant info although the oil leak is explained.
Year model, how many miles, which engine, and was the water pump replaced because of failure (shaft, etc) or because it was leaking coolant into the engine oil and so on? Or both.

There’s also the question of any overheating being involved and how severe if so. There’s also the question of whether this car is turbocharged and if the turbo is liquid cooled which could lead to coolant potentially entering the intake tract.
Details can make a difference…