rev up your engines, today I'm gonna talk about fuel filters in your car and what
damage can occur if you don't change them and they get clogged up, now fuel
filters of course, filter contaminants out of your fuel so they don't mess up
with your fuel system, and to understand how they work here's a little history
lesson, when I was a young mechanic in the sixties all cars had carburetors to
make fuel go into the car, and most of them had a tiny little brass filter like
this, that would filter out water and some impurities you can see it's just a
tiny little metal thing that went in the front of the carburetor, now the first
car I ever had was an Opel, yeah a German car shocked you doesn't it, it had such a
small gas tank, it was only ten gallon and it was metal it was rusting out, so
I put an inline filter like this to get rid of some of the crud, because I didn't
have any money to buy a new gas tank, but even though this is a reasonably sized
filter, rust sediments are so small rust kept getting into the carburetor, and it got
so bad that I would take the carburetor apart all the time to clean the crud
that went past the filter, and I didn't even have money for a gasket, so I used
the Kellogg's cereal box and I cut the gasket out and I had a bunch them lying
around so I could clean it out put another gasket in and go down the road
realize carburetor system, this is an old Volkswagen Beetle carburetor, don't have
much pressure, the fuel pump would put out one and a half pounds pressure or so
so dirt could get stuck because there isn't that much pressure pushing it through
but cars have been fuel-injected for a long time, they have higher pressure, it
can go anywhere from 40 psi up to the modern GDI engines that can have over
1500 psi pressure, now other cars like this 94 Toyota Celica, they had fuel
filters externally, here it is it's just a big canister there's a bolt on the top
and a threaded rod on the bottom and you replace the fuel filter every 40, 50
thousand miles, now this is a fuel injector, one that goes on that older one
and if you look inside look, at those tiny holes those are the little tiny
holes inside where the fuel sprays into the engine, you don't want to clog them
up, and many of them have a little screen just like a tiny mosquito screen on your
house window, to keep dirt from getting into the injectors and if any of them
get clogged up, your car is gonna run poorly, now if your fuel filter gets
clogged up it can do two main things, one it can lower the pressure that goes to
the fuel injectors, so if they don't have the right amount of pressure they can't
spray the right amount of gas into the engine, and if it's clogged up enough,
it can trip a code and turn you check
engine light on and when you scan it, it can say, engine running too lean,
well it's running too lean because it's got the normal amount of air coming in
unless your air filters clogged up, but the fuel filters clogged can't pump
enough fuel through, the pressures too low and then the car will run lean, now
eventually running lean can burn out your Pistons, make your cooling system
overheat and ruin the engine, and it can burn out your catalytic converter by
making it run too hot, now testing for a clogged fuel filter used to be easy in a
car, we used to just have pressure gauges quick install connectors, and on many
cars like Ford's GM's and Chrysler's they had a little Schrader valve just
like the valve on your tire, you would just snap and on and take the pressure
to see if there's any pressure problems like either too low or too high if the
fuel pressure regulator was bad, it was easy to do, but on most modern cars, hey
there's no such valve, in order to check the pressure you need a kit with all
these adapters, it's a royal pain in the butt,
here's some of my adapters I've got a box that's got three times as many, it's
a real pain taking fuel pressure readings in a modern car, plus if the
fuel filters clogged up sometimes there's enough room for the pressure to
be high but the volume is low, so when you're going at higher speeds it's just
does enough volume and you can't go fast and doing a volume pressure test is
another real hassle to do, so basically you want to make sure your filters clean,
but here's the stinker of it on most modern cars, you can look around all you
want under the hood, but you're not going to find a fuel filter because guess what,
they've hidden it away and wherever they hidden it, they've hidden it inside the
gas tank, engineers and our questionable wisdom, have decided it's more efficient
to have the filter right next to the pump inside the gas tank, well guess what
changing it out has become a gigantic pain in the rear end, now in the case of
this Matrix, it's not that big of a deal it takes less than half an hour to
change the filter, you just take out the back seat, there's a little four screw
cap that covers over the where the gas tank is and when you take that cover off,
you get inside gas tank and you can replace
the filter assembly, now Toyota calls it a fuel filter fuel pump assembly and
they want six hundred and ninety seven dollars, but aftermarket you could buy
just a filter itself and replace it, but the old saying out of sight out of mind
really fits it here, most people don't see it, they don't think about it and you
leave it alone, but a clogged fuel filter will cause the
pump, this is the tiny little pump that they use in Toyotas, to work too hard
then burn out, then you'll have to replace the $697 pump and filter
assembly, so really you don't want your filter to get clogged up, now I have to
admit, I live in Houston Texas a giant city, and all the gas tanks at the gas
stations have been dug up and they put in the fiberglass ones that don't rust
so you don't get crud in the gasoline from the tanks rusting and then water
intruding in the gasoline, so if you have a good supply of fuel you really don't
have to worry about it getting clogged up, but who knows sometimes I've seen
they made the gas wrong, and then when people pumped it, the car started to die,
the filters started to clog up, there's all kinds of things that can happen, water
can get in them, you really want to make sure you have a clean filter, especially
if you live in an area where the fuel quality is questionable, and if you drive
a diesel it's even more important, diesel believe it or
not, there's fungus that can grow inside the tank and clog everything up, so you
really need a good filter on a diesel and you need to change it a lot and
whatever you do, don't believe that nonsense that a lot of the manufacturers
say that, oh you don't have to change the fuel filter it's a lifetime fuel filter,
well what they mean is, it's lifetime if it clogs up and a fuel pump burns out
because it's clogged up, then you get to replace that $697 assembly and they make
a lot of money selling it to you, now you don't need to change the filters in the
modern car all that often, maybe once every four or five years or every 60,70
thousand miles, but as you now know it's a good idea to keep them clean
so if you never want to miss another one of my new car repair videos, remember to
ring that Bell!