I took my car in to my mechanic for two problems: constant LF noise and occasional severe rubbing/hot wheel, and O2 sensor causing check engine light to come on.
A month and a half later, 14 days in the shop, $2000 down, none of the original symptoms have changed, but new ones have been created and fixed. I’ve had to point out sloppy work: lug nut missing, logo cap missing, engine compartment covers missing… And it’s always just, I need one more day. I think he’s going down the wrong path too: ABS problem, when I think it is mechanical.
I only paid for stuff on 3 of these days in the shop, and the guy is nice enough, but I suspect incompetence. I think it’s past time to give up. But what’s the best course of action now? Preferably it doesn’t include spending another $2000 elsewhere without getting my money back.
[i] O2 sensor causing check engine light to come on.[/i] Don't assume that a CEL means O? sensor. That is only one possible cause.
[i] ABS problem, when I think it is mechanical[/i] Maybe maybe not. Why do you think it is mechanical? I can't make an informed guess based on the information you have presented yet.
I am not saying the mechanic is right or competent, just that I don't have anything that tells me one way or the other.
Good Luck
Sounds like now is the time to give up on your mechanic. The big question is how to find a new one. Sometimes dealers can be useful,
Sloppy work, missing parts and someone saying “I need one more day” are sufficient.
14 days in the shop? Outrageous!
Find a new mechanic.
I am not a car person, but I am an electrical engineer so I of course have a scantool because I like electronic things 
It is definitely the O2 sensor.
As for the brake problem, I figured I wouldn’t ramble on about the whole saga. But for a 30 second summary, wheel bearing and rotors have been replaced, he wants to replace the axle shaft. ABS light only came on after I brought it to the shop. The symptoms of the problem say ‘mechanical’ to me: distinct groaning noise from the caliper and delayed release when this problem occurs.
So now that I’ve decided I need a new mechanic, I’m unsure what to do about the money I already spent. I think I deserve a large chunk of what I spent back for various reasons. I don’t think the wheel bearings and axle shaft were necessary, he charged me $160 for a universal O2 sensor, charged me for the ABS speed sensor and install which I think he damaged replacing the wheel bearings…
Perhaps it would be best to patiently explain that while you understand that things take time, that you don’t have an infinite amount of it, and set a deadline.
Unless you want things to turn nasty, you will likely be out a certain amount of money, though I wouldn’t settle for losing the whole $2000. I’d just chalk it up to experience and leave with some good karma intact.
If the wheel/tire is really hot, then that might indicate a stuck caliper on the brakes. Depending on what kinda noise, the CV joint may be going out as well.
What year is this Mazda 3?
Definetly time for a new mechanic. I had an odd problem once, my truck was misfiring in first gear and I had checked everything that i could at home, spark, fuel, compression, and timing. So i took it to a shop, he said one of the coils was arcing out and he showed me the cracked coil so I said fine. It still misfired bad so I took it back and he spent another week, They could find nothing wrong so he said he thought something was up with the motor. I forgot to mention it sat for a year. Another shop spent another week on it and determined that it had bad gas. So the first shop I still trust as it was my lack of describing the problem properly.
- He says the cv join is torn, but while it may be, I don’t think it’s making the noise because it’s not consistent with descriptions of the noise this makes I’ve found through googling.
The noise sounds like the pad rubbing on the rotor once per cycle, like it was warped. The noise increases slightly then goes away as the brakes are applied. This has persisted through replacement of the rotors. The big problem seems to be that it is intermittent, and only happens after driving 15-20 miles if at all.
And you are wondering if you should stay with him? What does he have to do to lose your business, sleep with your wife? As far as getting money back-good luck!
Time for a new mechanic. I prefer independant mechanics, but sometimes there are just too many brands, models, and unique features that an independant mechanic can’t keep up with all the changes on all the brands.
Your car isn’t that old and at this point I think I’d go to a Mazda dealer next to get the problems properly diagnosed and fixed. Dealers aren’t perfect either, but at least the mechanics are supposed to get factory supported training and all the lastest factory bulletins for the brand they handle.
Dealers prices are higher, but a poor mechanic can cost you more chasing after the wrong problem.
Yeah, you’re not going to get money back from him. It’s the rare mechanic who is both a crappy mechanic and willing to refund your money when he fails to fix your car. Such types might be noble, but they’ll also be out of business in a week.
But you should have given up on him long ago. Sitting here on the internet, I’m guessing you have a sticking brake caliper. It’s probably been going on long enough that the slides are physically damaged rather than just not lubricated, and so you’ll need a replacement caliper. The hot wheel and the noise are dead giveaways. The mechanic should have suspected this before he even looked at the car.
I’d say he’s one of the new breed of mechanics who gets totally lost unless a computer tells him what’s wrong and what to replace, but it sounds like he hasn’t managed to fix the oxygen sensor even though the computer told him about it.
So I’m just gonna go with “He’s an idiot.”