Has anyone had problems with the threads when removing an oxygen sensor?
If so what would cause such a problem? Not enough heat? Too much heat?
Existing sensor too old?

Thanks

Well before you remove the upper O2 sensor, Its best to have you header to be a little warm, It makes it way easy to remove the O2 sensor, Its a good thing to use some HI temp anti cease sealant on the threads,

Well, I had one replaced at a garage recently and they told me that some of the threads came out along with the old sensor. As a result they had to re-tap the hole and then they charged me more than what I was initially quoted.
I thought I would check to see if anyone else has heard of this problem? Perhaps the mechanic did something wrong during the removing of the old O2 sensor by not using enough heat or perhaps too much heat (acetylene)?

When a price is quoted for a job according to "the book" doesn't that rate take into consideration the potential for problems?

Any feedback would be appreciated.

The technician may or may not have done something wrong. Impossible to say unless you were watching exactly what he was doing. Sometimes bad things happen, despite best efforts. Most shops will eat the extra time it takes to retap a hole, though, especially if there's any concern over it being their fault for damaging the threads. Retapping an O2 port in a manifold would only take 10-15 minutes maximum, anyway, so I'm not sure why they would charge you extra for that. Unless they replaced it with an insert or heli-coil, but even then....

Anyways, on the price quote...you have to check your own state's laws, as they can (and do) vary.

For example, in Washington state, only if the actual price exceeds 10% of the quoted price does the shop need to inform you and get authorization for the overage. If 10% or less, they can simply add it on as an unforeseen incidental (like the few minutes it takes to re-tap an O2 bung).

"Book Rates" do not take potential problems into consideration, but they do not assume that it's Speedy Gonzalez working on your car, either, so it all kind of averages out in the long run. Some jobs take longer than the book rate, some shorter. Problems created by the mechanic are the mechanics concern. Problems created by your car, or your (lack of) maintenance, usually get passed on to you in the form of a slightly higher cost.




-Ferrite