Oxygen sensor frequently malfunctioning

[mr.sajid808]

Hello Pakwheelers,

I need your valuable opinions and expertise regarding an ongoing issue with my Honda Civic 10th generation. For the past two years, I've been facing a problem with the oxygen sensor frequently malfunctioning, and unfortunately, changing the sensor hasn't improved the situation.

Recently, I reached out to a Honda engineer from the USA to seek some guidance on this matter. According to the engineer, there are certain symptoms I should check to identify the root cause:

1. Radiator coolant frequently decreases without any visible leakage.
2. The car feels underpowered, especially when the AC is turned on.
3. The car's mileage has decreased noticeably.
4. There are persistent error codes related to the powertrain, suggesting a wiring issue.
5. The air-fuel ratio sensor is also showing errors occasionally.

I have inspected the wiring and it seems to be fine. However, the fuel average is all over the place – on long journeys, it shows 15/16 kmpl, while in the city, it drops to 8/9 kmpl. Additionally, the coolant level remains low, which contributes to the sensor malfunctioning.

Based on this information, my engineer friend suspects that the issue could be related to the head gasket. He believes that the burning coolant might be causing the frequent sensor malfunctions.

Now, I'm at a crossroads and need your advice. Should I proceed with the head gasket replacement as suggested, or do you think there might be other underlying problems that should be diagnosed first? One thing to consider is that I'm from a small city, and I'm hesitant to take the risk of opening up the engine without a clearer idea of what might be wrong.

I'm eager to hear your insights and experiences. Your help would be greatly appreciated!

[syncview]

So, does it consume coolant?

[mr.sajid808]

Yes its does

[syncview]

no external leaks?

[mr.sajid808]

Yes there is no external leakage we inspected pipes carefully

[Hassan1991]

There are tools to check gasket leak without opening the head.

[Xulfiqar]

To check for a hot internal leak,

I dont think those tools are available at the dealer even.

What you should check is all hose connections for traces of seepage. Ive had a car like this, seemed like coolant burn but it was just an external leak which only showed up at 18 psi.

[mr.sajid808]

thank you for hint @Xulfiqar. We will check leakage with some pressure. Even leakage found why my o2 sensor frequently malfunctioning? Any idea

[syncview]

if leakage is found, fix it then test again for coolant consumption. if it still consumes coolant with external leaks fixed, that is the reason the o2 sensors are malfunctioning.

otherwise it could be wiring, bad placement of o2 sensor, or leaks around o2 sensor causing false readings.

[Xulfiqar]

Oxygen sensor is murdered by coolant or silicone residue (like using cheap silicone sealant on engine) or if engine burns coolant. It poisons it dead.