2002 SAAB 9-3 Alternator

Flat rate for removal and replacement is 1.4 hours.

Thank you for including the engine size AND for not asking for dollar amounts. My source shows this job should take 1.4 hours, but they don't specify if more time is needed with air conditioning or other variables like turbochargers. If this time is correct, it will be listed as such in the "flat rate" guides that most shops go by. That gives them the ability to be fair to you if an inexperienced mechanic takes longer, and it's fair to an experienced mechanic who may get done faster now that he has invested in expensive specialty tools and advanced training. All shops will quote you the same time. The variables are their hourly shop charge and other things they may need to charge for like shop supplies and the new "environmental" charges to help pay for the extensive government regulations they have to comply with.

Be aware that providing your own parts, whether new or used, has its pitfalls. This is like bringing your own food to a restaurant and asking them to cook it for you. If you aren't happy with the quality, you are welcome to bring some more, but you still owe them for their services both times. There ARE times when a shop may ask you to locate a part, particularly when the car is not a common model and it will take a lot of time to find those parts, but normally the shop will add a small markup to the cost of the part, just like any other store, then they assume the responsibility for getting it exchanged if it is wrong or defective, or if it fails within the warranty period. If that used generator fails in the first week, for example, you will be expected to find another one and to pay for the labor all over again. A lot of mechanics won't allow customers to supply their own parts because they've been burned too many times by people becoming irate when they're told the part is no good, or it wasn't what was needed to solve a problem, but they still have to pay for the labor. They'd rather have people be a little grumpy than being angry at having to pay twice.

That brings up another point. You don't want to trust a mechanic who is willing to blindly replace a part just because that's what you asked for. A conscientious mechanic will diagnose the cause of the problem first to increase the likelihood of your satisfaction with the repair. That diagnostic time is not included as part of the 1.4 hours.

This looks suspiciously similar to a GM generator, and those have a very high failure rate. The number of repeat failures will be reduced a lot by replacing the battery at the same time unless it is less than about two years old. If you have to pay to have a used generator replaced again, the typical labor charge will be close to $140.00 plus the inconvenience of finding another replacement. Now supplying your own parts doesn't look like such a good deal.

Be aware too that generators can not be fully-tested off the car. Generator test benches typically use a one horsepower motor to run the generator. On the car they can easily take over five horsepower to get maximum output. The best the seller can assure you is the unit is putting out something, but not how much it is capable of.

Once it is installed on your car, have the charging system tested with a professional load tester for maximum output current and "ripple" voltage. I found three generators listed for your car. They're 90 amp, 120 amp, and 130 amp units. During the full-load test, which only takes a few seconds, the generator will deliver very close to its rated value, or exactly one third of it. With one failed diode of the six, you'll lose two thirds of the output capacity. Even the smaller 90 amp generator is pretty hefty compared to years ago, but if it can only produce 30 amps, that is not enough to run the entire electrical system under all conditions. The battery will have to make up the difference until it slowly runs down over days or weeks.

With a failed diode, "ripple" voltage will also be very high. That is what leads to harmful voltage spikes, especially so on '87 and newer GM generators. Those spikes can damage the internal diodes and voltage regulator, and interfere with computer sensor signals. They are a big cause of elusive engine running problems that defy diagnosis, AND those repeat generator failures I mentioned.

The battery is the key component in damping and absorbing those voltage spikes, but as the lead flakes off the plates as they age, they lose their ability to do that. That's why I wanted to mention this. If your replacement generator is capable of developing its rated current, please be sure to look at the battery and replace it if it's over two years old. If you don't, and it causes your new generator to fail, you'll be making another 130-mile trip.

The most common failure in a generator is worn brushes, and those CAN be verified as working on a test bench. You didn't list the mileage so I can't make any judgements there, but if the replacement generator came from a car with mileage similar to yours, you might expect the same failure soon. Of course you won't know the history of the part you're getting. It could be a rebuilt unit that was just installed, then he guy piled up his car a week later. You run the risk of getting a generator that's just as good as a rebuilt one from the parts store.

I understand that family and friends are happy to have you get the part because that lets them off the hook if it fails but the labor should cost less because they're your friends, not because you got the part. Their labor charge should be the same regardless where the part came from.

There are two potential problems to be aware of. First of all, if you can determine the current rating of the old unit, and the new one is the same, you have nothing to be concerned with.

If the car came with a 130 amp generator and you install a 90 amp unit, there may be times when it won't deliver enough current to meet the needs of the electrical system. That is a very low-level worry, so to speak, because the battery will make up the difference, and you won't need that high current for very long. Head lights, fuel pump, heater fan, wipers, rear defogger, and radio might require a total of 60 amps. Anything else like power windows and mirrors would just be for a few seconds, so that won't run the battery down. The 130 amp generator was installed to cover any combination of electrical systems on your car but there's no chance it is going to have to actually develop that much current in normal operation.

The bigger problem can occur if your car came with the 90 amp generator and you install one of the larger ones. First you must be aware that 130 amps refers to maximum capacity, not what will actually be developed while you're driving. If the car's electrical system needs 73 amps, the generator is going to develop exactly 73 amps; no more and no less, and it doesn't matter if it's capable of 90, 120, or 130 amps. The only time it will develop its full maximum value is during a load test with a professional load tester. The test involves loading the electrical system down just enough to make the generator develop its highest possible amount of current, but only for a few seconds. The test is done just long enough for the mechanic to get the reading.

Where the problem comes in is there is some type of fuse in the fat wire going from the generator back to the battery. Very often the size of that fuse is selected based on the capacity of the generator the car came with from the factory. On older cars that was usually a "fuse link wire". That was simply a few inches of wire with a smaller diameter so it was the weak link in the chain, and the insulation was designed to not burn or melt. Being a wire, it takes some time for excessive current to burn it open. If yours is sized for a 90 amp generator, it will not burn open during the load test because 90 amps is the most you'll be able to get, and the link can handle that. But now, if you install a 120 amp generator, it will still be fine during normal operation, but doing that load test is not "normal" operation. If the test is done properly so it just takes a few seconds, the fuse link won't burn open that quickly, but if an inexperienced mechanic dilly dallies around and takes too long, the link could burn open. Most of the time the rest of that wire can handle the higher-output generators so the fix would be to just replace the burned fuse link with a larger one sized for that replacement generator.

Most newer cars use a large fuse that's bolted into the under-hood fuse box and those aren't as forgiving as a fuse link wire. During the load test, if the replacement generator is capable of developing more current than that fuse is rated for, the fuse will blow instantly. No further testing is necessary because now you know the generator is working. All that's needed is to replace the blown fuse. In this case, unless I learned differently, I would install the same size fuse that was removed. The car's electrical system isn't going to want more current than before, so even though the new generator has a higher capacity, it's never going to develop enough to blow the fuse during normal driving. The reason I wouldn't install a larger fuse is because I don't know if the circuits in the fuse box can handle that higher current. With different options on the car that demand that higher current, that may include a different fuse box. By sticking with the original size fuse, you'll know everything is protected properly.