rev up your engines, today we're gonna try to figure out why this Nissan is
overheating and like any car you got to start somewhere
there's a dozen different reasons the car can overheat, you got a pin pointed
and the first thing is the most logical, you pressure test the system and I got
this new toy I can't wait to try it out, now to pressure test the system you take
the radiator cap off, but unfortunately there are a bunch of different sized
radiator caps on cars nowadays, and rather than buy every single adapter and
there are dozens of them, this Pittsburgh kit that I just got is cool, cuz it's got
a main adapter and then different sized plungers that go in to seal the radiator
so when you pump it up you see if there's a leak in the system, in this
case it's a small one that fits in, so we put that inside here, it just spins in
then the whole assembly goes over the top and a little notches hold the side here
and then you just spin the top here until it gets tight, then you get the
pump and attach it here and we pumped it up to about 15 pounds we'll let it sit
and see if it loses pressure, patience is indeed a virtue you wait five ten
minutes see what happens to the pressure, and in this case it really hasn't lost
any pressure so we know the system is not leaking that it's intact, and just in
case those are really small like we'll look under see if it's dripping anywhere
from all that pressure, but now it's not dripping anywhere so it's not leaking
remember always start with the most obvious things the pressure testers
indispensable for finding overheating problems start simple, so we'll put the
cap back on and do another test, we'll start up the car
and let it warm up a little, well Check the gauge and when it
starts to get warm it should build some pressure up, we'll wait a few minutes
until the gauge gets closer to the middle, and while we're waiting you will
turn on the AC to see if the cooling fan works, turn on the fan and put the AC on
now you can hear the cooling fans are blowing like mad so they're working, so now that
the temperature gauge is in the middle that it's warmed up, this should release
some pressure when we release it, as you can see it hasn't released any pressure
which means that the radiator cap is bad it's not sealing it, so we're sticking on
the new radiator cap and taking it for a ride, because nothing beats road testing in
a car when it's overheating you have to, do a highway drive and city driving
do all the different parameters to see if it's gonna overheat again or whether
it's fixed, and well after half an hour of driving no more overeating, so now
it's fixed well how does that work, your radiator system is a pressurized system
most of them are about 15 psi now, when I was a young mechanic it was a lot less
because the radiators were bigger, but guess what
bigger radiators cost more money to build, so for ages they've made smaller
radiators and they upped the pressure, so if you have more pressure in a smaller
radiator, it can do the same cooling as a bigger radiator that has less pressure in
it, but of course with modern cars if you do lose pressure on the radiator cap and
it's not holding the correct pressure, the car will overheat faster because it
won't have enough pressure to keep the temperature from getting too high and
then steam will start escaping from where it's not holding pressure, and it
will lose coolant through steam and eventually it'll just bubble all the
coolant out when it starts to boil, so you want to make sure your radiator
system is holding pressure, the pressure tester that shows that the system itself
on the vehicle is holding pressure, and the cap itself that's the ultimate
sealer on top of it, if it's bad you lose pressure and it will overheat, so nowadays
it's probably not a bad idea every three or four years just put another radiator
cap and stick it on your radiator when the engine is cold, so you can prevent
from happening, because they are spring-loaded the springs wear out, the
rubber gets corroded, they do eventually wear out and they don't cost that much money
and you might also want to take my advice, this is an aftermarket cap that
was on this old Nissan, I put a factory cap on, the factory ones are generally
much better made, sometimes the aftermarket ones, hey I've had them not
work right out of a box, so now you know how to diagnose and repair your car when
it starts to overheat, so if you never want to miss another one of my new car
repair videos, remember to ring that Bell!