Excuse me for butting into your conversation but I'm compelled to add a few comments. First of all, your oil wasn't over-filled. To cause it to spill over would take a good 30 quarts, probably more, to completely fill the engine. Anyone with an ounce of common sense would recognize they were doing something wrong long before they put that much in. What most likely DID happen was the guy just plain spilled. We all do that from time to time. Typically we just wipe off what we can reach and let the oil burn off that runs into tiny inaccessible places.
The next thing is you have to look at the diagnostic fault code rasmataz wants you to have read. Even though the Check Engine light turned off, those codes will stay in memory so they can be read. You must be aware though, fault codes never say to replace parts or that they're defective. They only indicate the circuit or system that needs further diagnosis. It is true that oxygen sensors use outside air for comparison to the amount of unburned oxygen in the exhaust. The outside air can be blocked by an exuberant rust-proofing technician who coats the sensor with that material. That, and oil, do not destroy the sensor. They simply prevent it from doing its job. The proper repair is to wash it off.
That's where the fault codes come in. There's about a dozen different fault codes related to an oxygen sensor and they point to different failures with different fixes. About 3/4 of the codes refer to an unacceptable condition being reported by a properly-working sensor. Of the rest of the codes, probably half are the result of a wiring problem related to the sensor. An oxygen sensor will only solve a fault code less than half of the time there IS a code.
Also, when you DO need to replace an oxygen sensor, you don't replace all of them. There is no magic time or mileage at which they begin to fail, and they don't wear out at the same rate like tires or spark plugs do.
Finally, you can get an idea of the seriousness of a fault code by how the Check Engine light acts. There's well over 1000 potential fault codes, and about half of them do not even turn the light on. Codes that refer to something that could adversely affect emissions must turn the light on. If that problem is relatively minor, the light will turn off while you're driving when the problem goes away. If the problem is a little more serious but it goes away, the light will stay "latched" on until you turn off the ignition switch and restart the engine later. If it's still more serious, the light will turn on anytime the engine is running, even if the problem stopped acting up a while ago. For all of those conditions you can keep on driving, often with no noticeable drop in engine performance, but the codes should be read as soon as possible. Many minor and inexpensive problems could turn into expensive ones if the cause is ignored.
It's when the Check Engine light is flashing that you must "bail out and run for your life". Actually, it means stop the engine right away to prevent damage to the expensive catalytic converter(s). Too much raw fuel is going into the exhaust system and the catalytic converter is going to overheat.
The other clue that this is not related to the spilled oil is the problem did not occur right away. All engines have oil leaks when they get to be a few years old, and if oil spilled three days ago would cause a problem, cars with constant, very small leaks would all be developing the same problem. In reality, any leaking oil that headed toward an oxygen sensor would vaporize and burn off long before it reached it. Oxygen sensors don't even start to work until they reach 600 degrees (F). Oil in the engine will barely reach 250 degrees, and at that temperature it is already starting to vaporize. If your mechanic DID manage to spill enough oil onto a cold sensor, it would have burned off in a very short amount of time. That oil would not wait three days to cause a problem.
What I would do is record specifically what the fault code said, then erase it and see if it comes back. Either get the exact code number or its description. The codes get very specific and each one has its own troubleshooting steps. If your mechanic just says it's an oxygen sensor code, that's no more helpful than saying "tire" or "wiper". You have no idea if one has a problem, all have the same problem, something is worn out, etc.
Monday, September 30th, 2013 AT 12:14 AM