Why Not to Buy a Car with Stop/Start Technology - YouTube

rev up your engines, today I'm going to talk about that modern auto stop-start

system that some cars have, where your driving down the road and when you come to a stop and

you're sitting, it turns the engine off, and then when you step on the gas it

starts back up and runs, now these auto stop and start systems are made to save

gasoline and they really started full-time in modern hybrid cars like the

Toyota Prius, now auto start-stop works great in hybrid cars, because they were

designed that way, to begin with, a hybrid car doesn't have a tiny little

starter like a normal car that runs on 12 volts, it uses the generators inside

the car to actually start the engine using a five hundred volt battery, so

it's no problem for that giant battery that's in the trunk of the Prius to

start your car up and down and up and down, it's got a lot of power, but most

cars still have these lead acid batteries they're smaller they're not

made for continually starting and stopping the car, for these kind of apps

you need a deep cycle battery, most cars still use a lead acid, they're not really

deep cycle, lithium ion like in the Prius are, but when you think about it

they're making cars cheaper and cheaper, they're not going to be putting more and

more expensive batteries in the cars just for this, and as I've already said

in hybrid cars, they use these giant motor generators to start themselves up, on a

regular car they're using these tiny little starters, they're not made to be

used over and over and over again, now granted some of these auto stop start

cars do a more robust starter, but it's nothing compared to the generators

that they use in the Priuses or any hybrid vehicle, these things are tiny

compared to those huge things, and you might not think about possible engine

damage from starting and stopping all the time, but I'm a mechanic and I think

about it, realize that your crank and your rod bearings get worn the most upon

startups, and in a normal car, they usually good for a hundred thousand starts

and stops before they start to wear out, and that's fine for a normal car that

you start up driving around then later when you shut it off you start it up, but

with these things, you're going to be starting and stopping a lot more often

so you'd need bearings that were good to 300 or 400 thousand of these cycles, so

if you have start/stop in a normal engine, hey it's going to wear the rod

bearings and the crank bearings, and then you're going to have to rebuild the engine

it's something that a lot of people aren't going to think about, but being a

mechanic, I think about that stuff and when I see damage that shouldn't occur

I'm not for that system, and then let's get down to the nitty-gritty, how much

better gas mileage do you actually with one of these Auto stop-start systems

well they advertise that they get between 3 and 10 percent better gas, much

but you're only going to get 10 percent under very limited conditions, the

temperature outside has to be moderate, between 40 and 85 degrees, higher or

lower you're not going to get much, and if you run the AC, you're generally going to

get less than 3% better gas mileage, because air conditioning uses a lot of

power, this isn't like you're turning your whole car off by turning your

ignition key off, it shuts the engine off but other systems are still operating, so

if it's hot outside after a very short period of time, it's going to have to turn

the engine back on to run the air conditioner, now like I said previously

these systems work fine in hybrids like the Prius, because the Prius's use

electronic air conditioners and they got that big old five hundred volt battery

in the back. so even when the engines not running. it can run the compressor with

that 500 volt battery and you still feel nice and cool. inside but a normal car

doesn't work that way, now truth be told, there are a whole bunch of different

auto stop start systems out there, some of them that I've seen in Europe heck

they use the alternator to start and stop the car

the alternators in those cars just spin the serpentine belt and instead of the car

driving the alternator, the alternator is spinning to make the engine go, and some

of them have electronic water pumps like BMWs, so the engine won't overheat if the

car isn't running while it's sitting there, because realized when you shut an

engine off, it's got a lot of heat in it, it's what's called heat soaking, it's

just sitting there heat soaking it actually gets hotter, so the cooling

system still has to be doing stuff even though the engine is shut off, and sure

engineers can bypass these problems with some really high-tech

technology, but really when you think about it, all this technology

that's going to break down the line and be really hard to fix, do you really want

that to get a little bit less than 3% better gas mileage if you run an air

conditioner, it doesn't intrigue me, and for many people there's just the

annoyance factor of, your driving and when you stopped on the engine shuts

itself off, now they all do have a button you can push that turns the system off

every time you start the car, if it drives you nuts, you can push that button

and turn it off, and me I find it rather annoying, every time I get a rental car

or I'm road test in a car that has that system on, first thing I do is push that

button off so it runs like a normal car, because if you want really good gas

mileage and all these technology features, heck go out and get a hybrid

like a Toyota Prius, they were designed for that, because really when you think

about it, these auto stop start systems they're kind of like a halfway measure, you

know, they work fine in the hybrid cars, but in a gasoline car, it's trying to turn

them into something that they really weren't meant for, since I'm a mechanic and

these systems have been out a little while now, they're starting to break, I

have to fix them, let me tell you they're no fun to fix, and you're not going to be

happy when you get this giant bill for fixing them right,

so if you never want to miss another one of my new car repair videos, remember to

ring that Bell!