When customer calls and asks to change timing belt, do transmission flush or replace balljoint there is very slim chance to come across something unknown or unexpected. Even if you never done such a job on some particular model you can read through the procedure in shop manual (or even watch video on YouTube) and get a fair idea of what it is like. You can come across some seized bolt or stripped thread but any other surprises are quite unlikely. For the job like this I can give an estimate (I mean no-obligation-rough-estimate) without even looking at the car. If you need written-in-stone-quote than I have to inspect your vehicle first, but in most cases it would be quick and free of charge inspection.
Much more often customer calls with his concern description like “there is a banging noise from the front on rough roads” or “there is water on the floor when it rains”. In such a case it could be something obvious like broken shock or it could be very mysterious like water that seems to be appearing from nowhere. As a matter of fact water leaks are one of the most difficult concerns to diagnose. Some noises are difficult to find too.
When it comes to electrical or driveability troubles simple and obvious things are rather rare. Blown bulb, disconnected vacuum hose or broken wire right in plain view – that’s about it. Even blown fuse could be not so easy to locate. Typical in the past inspection step “check all fuses” could get tricky to perform when there is number of fuse plates in different corners of a vehicle with over a hundred of mini and maxi fuses combined. Some of them if pulled out for inspection could cause control units to reset resulting in unexpected effects. Plenty of times I had vehicles that have been brought with comment “we checked all the fuses and all good” and found another blown fuse in location that owner did not even think about or didn’t notice. There is another question arises after you have located that blown fuse – what caused it to blow? If I replace a fuse and it blows right away – I consider myself lucky, short circuit is out there right now and it would be much easier to find it like this. If fuse does not blow right away – than there is a great possibility that hours of diagnostic time would be required to find intermittent short or intermittent high current condition. Typical diagnostic nightmare is about to begin ;-).
Therefore whenever I have a request like “my Check Engine light is on” or “my electric window stopped working” there is no way to say right away how much it’ll cost to fix. There is no way to say how long it’ll take to diagnose the problem either.
Providing a quote for cost of diagnostics is absolutely impossible. If I would know in advance where is the problem I would know how long it would take me to find it… but hey, if I already know what is the cause of concern then I don’t need to spend any time on diagnostic at all! This is the most stupid question diagnostic technician could be asked: “How long this is gonna take you to figure out what’s wrong?” You can’t even say “I don’t know” (that would be the most natural and true answer) because these words are banned in conversation with customer. “I don’t know” is a magic sequence of words that annihilates customer’s confidence in you. You are mechanic, YOU HAVE TO KNOW. Go and get your magic crystal ball, for gods sake!
At the dealership I have no way around other than request certain diagnostic time and get it approved by customer in advance. Dealing with warranty repairs is another issue that I don’t even want to talk about – it is bad. At least we have a policy when one hour of diagnostic time is more or less approved by default so you are not totally in the dark when doing your quote. The worst thing that happens is when customer approves only fraction of diag time that you requested, like one hour instead of three that seemed to be needed. Then you practically limited to the least intrusive random checks here and there, especially considering that within that time you have to write down diagnostic report and put all the things back together if you started to remove or disassemble something and kick the car out on the parking lot. Then few hours later customer approves (or not) another hour or two and you start all over again: bring the car in, remember where you stopped in your diagnostic process last time, remove some parts and components for access, check couple more circuits… hey, you have already spent 45 minutes, and you have 15 minutes left to put everything back together, write a report… Ar-r-r-r-gh! What else you can do to make my job even more difficult!? Yes, I know, dealer’s time is very expensive. Trust me, there are genuine reasons for it, financial greed is not on the top of that list of reasons.
So don’t be surprised when dealer can’t “fix right first time, in time”, flat rate environment is not favorable for diagnostic research.