Busted oxygen sensor on my car: safe to drive?
November 20, 2013 5:54 AM   Subscribe

Looking for second opinions. My car has a busted oxygen sensor, and it can't get fixed today. Tomorrow I'm supposed to start driving for Florida. Is this crazy?

The car is an 2009 Hyundai Elantra. The "check engine" light came on, so I've had it looked at and the computer says it's a bad oxygen sensor, which, if I understand it correctly, effects fuel efficiency. The car guy says it's "probably" ok to drive it to Florida; I might lose some mileage, but that's all. Does this sound right?
posted by JanetLand to Travel & Transportation (16 answers total)
It should be fine. I doubt you'll notice any difference in mileage. Get it taken care of once you get to Florida.
posted by Thorzdad at 5:59 AM on November 20, 2013

Is it still under warranty? If so, see if you can get it replaced today. Only because of terrible fuel efficiency. 1500 miles is a long trip if you keep having to stop for gas (even if you don't!)

It won't hurt anything on your car. If you can live with crappy milage, go for it.
posted by Ruthless Bunny at 6:06 AM on November 20, 2013 [1 favorite]

The oxygen sensors in the car are used by the computer to determine how much fuel to add to the mixture for combustion. It's important for the engine to burn very close to stoichiometry (that is, just enough fuel is added to completely burn all the oxygen in the cylinder) so that the catalytic converter can work effectively.

Not having the oxygen sensor is more of an emissions issue than anything else. The car's failover condition is probably to err on the side of more fuel than is necessary to prevent the engine from running rough.
posted by backseatpilot at 6:06 AM on November 20, 2013 [1 favorite]

A bad O2 sensor can damage your catalytic converters. Those are spendy to replace.

Do you live in a place that does emissions testing ? You might consider getting the sensor fixed sooner if you do. It should be an easy(ish) fix, although some of them are located... inconveniently.

But yeah, your car won't blow up or anything.
posted by Pogo_Fuzzybutt at 6:28 AM on November 20, 2013 [1 favorite]

What 'car guy'? My oxygen sensors have usually been pretty cheap and quick to replace. Is this your repair person or the guy at the parts store who loaned you their code reader?
posted by tilde at 6:39 AM on November 20, 2013 [1 favorite]

Response by poster: This is my repair person -- he can't fix the car today because he has to order the part. I called the closest Hyundai place and they can't fit me in today to fix it even if they have the part.
posted by JanetLand at 6:43 AM on November 20, 2013

Dang. Well, what about getting a recc en-route? Or get it fixed while you're in Florida? I've got one recc in SE Florida, but if you're still driving from MA I'd possibly even get the darn part from the dealer and take it do your guy? I know part of the money he makes on the repair is for buying the part, so pay more in labor to cover it? Then again I'm in a kinda metro area so it's not unusual to be able to get a part the same day if it's not too uncommon - and I don't know if the dealer will even sell it to you over the counter. Dang.
posted by tilde at 6:59 AM on November 20, 2013 [1 favorite]

What stops you driving to Hyundai, picking up the part, then taking it to your mechanic to get it fixed? I appreciate time is tight but does the mileage preclude this option?
posted by MuffinMan at 7:02 AM on November 20, 2013 [2 favorites]

The default for the computer when the O2 sensor is bad, is to run the engine rich. Not a problem around town, but hours at high speed may mean that you clog the catalytic convertor.
posted by 445supermag at 7:03 AM on November 20, 2013 [1 favorite]

You can also search for the part on NAPA's website, they will show if the local stores have it in stock.
posted by 445supermag at 7:04 AM on November 20, 2013

Best answer: Did your repair person say whether it was the upstream O2 sensor or downstream? As explained by others, the upstream sensor helps the computer set the proper air/fuel ratio, and running too rich for too long could damage the cat. However, the downstream sensor basically just monitors the cat, and a bad one shouldn't affect your a/f ratio or mileage, or cause any additional damage.
posted by bradf at 7:52 AM on November 20, 2013

Your failed oxygen sensor may be covered under your vehicle's mandatory emission system warranty. A 2009 model would definitely still be under the warranty period which usually last something like 8 years.

Exact warranty coverage varies by state. I'm not sure if the Federal warranty law covers oxygen sensors. In California, the O2 sensor would almost certainly be covered (CA state law covers more parts and systems).

Check your specific vehicle warranty to see what is covered. It's probably in a little booklet stored next to the manual. The emission system warranty is probably in a separate chapter or appendix from the normal manufacturer's warranty.

If it looks like oxygen sensors are covered, take your car to a dealer to have it fixed for free.
posted by ryanrs at 8:04 AM on November 20, 2013

I was in a very similar situation with a car I used to own. Halfway through my drive from Indiana to Colorado, the car started jerking violently, not going more than 35 mph on the highway, and blowing out huge clouds of black smoke. Luckily I made it to a small repair shop in Kansas, where they replaced my catalytic converter. I replaced the oxygen sensor upon getting to Colorado. It was a huge pain and I wish I had just replaced the oxygen sensor from the start, which would have delayed my trip but would have saved me a ton of money and trouble. I wouldn't drive the car further than across town if you have a choice.
posted by Fuego at 12:28 PM on November 20, 2013

My O2 sensor went out on a trip in hilly area. Car didn't run as well but I was able to drive it. Would have rather had the O2 sensor though.

Can you get it fixed tomorrow morning? Or pick up the part at the store yourself? The drive might take longer with a bad sensor.
posted by yohko at 1:47 PM on November 20, 2013

I ran with a broken O2 sensor on my 2007 Mazda 3 for weeks including daily commutes. It was fine. Never noticed any difference in how it drove.
posted by olinerd at 2:42 PM on November 20, 2013

Response by poster: In case anyone's checking, the car did make it to Florida without mishap. It will be fixed Monday. Thanks for all the help.
posted by JanetLand at 5:03 AM on November 24, 2013

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