Sometimes I bring my car to the shop and they call me late in the day around 3 or later and tell me the problem and the cost to fix it. I tell them to do the work and they fix it by 5. I am wondering if they have already started the work assuming I will give the OK if it’s not a major repair? Could be a small thing like a blown fuse or belt replacement.
It really depends on the issue but most likely they have followed the diagnostic tree for your car and have found the problem and the suggested replacement part. This may or may not involved putting the car on the hoist and/or pulling anything apart yet.
I’m not a mechanic but it seems to me there’s little to no benefit of starting work that hasn’t been approved. If you said “no,” they wasted an hour or so taking your car apart and now they have to put it back together for nothing. I’m certain they have other stuff to work on while they wait for your approval.
I mean, certainly they did some work diagnosing the issue, but they’re not standing there with the phone in one hand and the replacement part in the other, waiting for your “yes” to screw it on.
How often do people say “don’t fix it” for a minor issue that’s $200 or less? I would think that’s pretty rare . This is an area with pretty high income so I don’t think people are going to bat an eye at a small repair.
Not a mechanic, but I’d assume in most cases, they either have your car up on the lift or attached to the diagnostic computer and, as noted above, they know how long it will take to fix and have the necessary parts. My assumption is that time to diagnose is included in repair time.
I think the main issue is time needed to get the part if they don’t have it. Maybe they can get the part in a hour from a parts store or the dealer. We have plenty of dealers close by for all makes.
I am somewhat curious, tho. My wife is a luthier, and just the other day she commented that you often don’t know how much work an instrument will require until you put some effort into it, even take some things apart. She does not usually charge “inspection/diagnoses” fees.
I’m assuming that a garage simply includes as overhead most time spent diagnosing problems for which repairs are not authorized. Like someone said, I bet most repairs under a certain amount are routinely authorized. If a more major repair is likely, I could imagine a shop charging up front for time diagnosing and assessing.
also if I say don’t fix it and they bought the part they can return it for a refund in most cases.
I don’t know the answer to “how often” in general but I have done this plenty of times. If my shop calls me and tells me I need maintenance that is not in the manual, I tell them no. Transmission power flush is a big cash cow, for example.
Regardless, if the shop performs work before it is approved then it is taking a risk. I have never heard anyone say that they declined the work but the shop did it anyway.
I used to be a dealership mechanic. We would give one hour of free diagnostic time IF you then opted to do the repair. If you declined the repair then you had to pay the 120 dollar charge for the hour of labor.
When you work at a dealership you see the same problems over and over and can do the repair quickly. For the most part I was doing the same 30 repairs over and over and over. The 30 things would change as time went on and recalls were issued and new models came out, but it was a very repetitive job.
So yeah, they might tell you the car needs an oil pan gasket at 3pm. But that’s probably the 5th one the tech has done that week and he has a special wrench that he only uses for 06-09 VW Passat oil pan gasket jobs that allows him to do the job very efficiently. That was my experience anyway.
We never started stuff without approval. The shop usually had one or two extra bays and your car would be moved there while we waited for approval. The tech would move on to something else in the meantime. If there was nothing else to do then he would clean the shop or organize his tools.
I’d imagine you could give them a conditional OK. I assume when they call you they call you not only with a diagnosis, but also a quote for the repair. You could probably just tell them if it’s less than $XXX, go ahead and fix it right away.
If they can call you at three and have it fixed by five, isn’t it likely that they just got around to looking at it? I can’t see any advantage to them diagnosing it at 9:30 in the morning and calling to get your OK at 3.
Yes, they can. At least in most cases, assuming the part hasn’t been installed yet. Also, if they’re a busy enough shop and it’s a common enough part (ie fuel pump for an F150 or ignition coil for a Civic), they may just keep it and hopefully have a use for it in the near future.
One of the mechanics I watch on youtube always always always (well, almost always) does a thorough diagnosis before replacing anything. He absolutely refuses to launch a parts cannon at a vehicle. However, it a good number of his videos, when he finally makes the diagnosis and he’s sure about it, he’ll mention that he had a feeling that’s what it was going to be based on the customer complaint so he already ordered the part and it’s already here. (But he’ll still make sure it’s what he thinks it is before installing it).
I worked in a shop after the military, and sometimes, yeah, if we had a car diagnosed, but didn’t have the part in stock, we’d make sure we could get one before we called. Or if it was the day the truck with new stock was coming, the supervisor might wait until the truck came, around noon, to see what arrived on the truck. A call to confirm the truck was bringing the part was really only about a 90% guarantee that the part was on the truck.
Yeah of course, that’s what the hour is spent on. Also on the common repairs, someone in the shop will usually have a known good part that we could use as a test. So if I suspected the problem was a fuel pressure sensor. I could break out the scan tool to see what the sensor is reading and connect mechanical gauges to the system to see what the actual pressure is. Or I can just plug in the known good sensor that Greg has in his tool box and see if it fixes the problem right away.
Not to say that you didn’t have guys who just took guesses. Usually those were techs who didn’t go to any kind of formal training so they didn’t understand how the system they were working with actually worked. So they had the mindset of “The last 10 times a car was doing X, the solution ended up being Y, so lets just go with that.”
Then when that didn’t fix it they had to start making up stories to explain the misdiagnosis.

Could be a small thing like a blown fuse…
Am I the only one wondering why a mechanic’s shop would be necessary for a blown fuse? Surely anyone would check the fuses first before assuming there’s a serious problem that caused an electrical failure.
I think you overestimate the mechanical knowledge of the average person. I’ll bet if you ask 10 random people if they know how to check their car’s fuses, half of them don’t even know cars have fuses.

Am I the only one wondering why a mechanic’s shop would be necessary for a blown fuse? Surely anyone would check the fuses first before assuming there’s a serious problem that caused an electrical failure.
If you don’t know anything about cars and one day your front right headlight goes out and replacing the bulb doesn’t fix it, what next? It’s almost certainly going to be faster and easier to take it in than try to figure it out yourself. Sure, a youtube video might point you in the direction of your fusebox, but it’s also going to mention things about relays, using a voltage tester to find a broken wire. It’s very quickly going to get overwhelming.
And that’s for something obvious, like light that won’t turn on. If your car won’t start it could very easily be a blown fuse for the fuel pump, but most people aren’t going to think of that and a mechanic likely wouldn’t even start with that.
Having said all that, lets say you KNOW it’s a bad fuse. Do you know where your fusebox is? Do you know where the other fuse box is? Are you physically able to get to it? The underhood fusebox in a Chevrolet Express is an effin nightmare to pop the cover off of since it’s under other things. The interior fusebox on my Civic is the most difficult location for an interior one I’ve ever seen. It’s in one of those spots where you have to sit outside the car and lay under the steering wheel to get up under the dash, with a flashlight and some advanced knowledge of what you’re going to be looking for.
Think about where a normal fuse box is. You open the driver’s door and it’s right there behind a piece of trim. On this car, that’s where it is, but facing inward so you have to get up under the dash to access it.
a woman took her car to Ford dealer for a problem. She said it was a Fiso. they had never heard of that model and they looked and realized it was a F150.
Is the crux of the question why it took so long to diagnose and call versus the time to actually do the repair? Because if I get a call at 3:00 I assume they didn’t actually start diagnosing the car until probably 2:00 (the whole rest of the morning and early afternoon it was sitting in the lot while they worked on other cars). So nothing about this scenario strikes me as unusual in any way. Even so, sometimes it can take a while to diagnose a problem, but once you’ve figured it out, the fix is a simple parts swap.
My question really is they seem to make fixes really fast but I guess for routine stuff it may only take an hour or less?
Car is in the shop right now and these guys never seem to call me before 3 but I took it in yesterday so maybe I get an earlier call today. Check engine light is on but the car seems to be OK. RAV4 with 130k miles.

Am I the only one wondering why a mechanic’s shop would be necessary for a blown fuse? Surely anyone would check the fuses first before assuming there’s a serious problem that caused an electrical failure.
In addition to what others have said:
How often does a fuse blow that isn’t a symptom of some other problem?