How to Tell if You Need a New Catalytic Converter in Your Car


one, two, three, four! Rev up your engines! It’s time for the Scotty Kilmer Channel today I’m going to help you answer the
question, does my car really need a new catalytic converter, now catalytic
converters do go bad on cars, but they’re relatively expensive and you just don’t
want to guess, you want to test to see if it’s really bad and that’s where this
OTC exhausts back pressure gauge comes in very handy, because when Cadillac
converters go bad, they clog up the exhaust system and build up way too much
pressure and you can easily test the pressure with this cool little gauge, you
simply unbolt the oxygen sensor that’s in front of the catalytic converter, then
take it out a hole and in this case it’s an older car, so you just push the gauge
in with this rubber adapter to measure the pressure and on newer cars where
the oxygen sensor has a thread that screws the whole way in, you just use this
little adapter that then screws in and the tester screws into this, then push it
in the hole and start the car and in this case, it was going between
six and five psi, it should be about a pound and a half, anything over three,
shows it’s really clogged up inside the cat needs to be changed, because in a
normal running car, the back pressure should only be one and a half pounds to,
and what’s happening is this, catalytic convert with the flashlight behind
here, have a little honeycomb in them, and they will clog up with burnt oil and
stuff and then the pressure builds up and often the temperature gauge will run
a little bit hotter, because the exhaust gases are staying in the engine too
long, making it run hotter, or the car will only go up to a certain speed and
no further, maybe it will only go 40 miles an hour, it won’t go past 40 miles
an hour, but of course there’s many things that can make a car overheat or
not go past a certain speed, that’s why you want to check the back pressure, to
see if it’s catalytic converter first but of course realize things are never as
simple as they seem, if you do have back pressure before the catalytic converter
gets too high you also need to check it behind the catalytic converter,
because if you find it still as high pressure behind the catalytic converter, then
it’s the muffler that’s clogged up, but in this case, it only had one pound
pressure after the cat, so it’s the cat that was clogged up, if it would have had
just as much pressure 10 pounds after the cat, then the muffler would have been
clogged up, and yes realize that this could happen, because if a catalytic
converter gets so bad, sometimes pieces of it will break off, then it’ll go back
and jam up and plug up the muffler too sometimes you have to change both a cat
and the muffler if everything got clogged but using this gauge, you’re not
guessing anymore, you’re going to be able to pinpoint where the problem is without
just guessing with expensive parts, so the next time you think you might have a
bad catalytic converter or someone tells you they think it’s bad, don’t guess, test, and remember,
if you have any car questions just visit the Scotty Kilmer channel and I’ll answer him as soon as I get
done talking with this dolphin

About the Author: Michael Flood

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