Instrument Maintenance
Exercise 4.7 Transcripts
Note that laughs and other noises and simple comments have been omitted. No attempt has
been made to distinguish between the two hosts.
Extract 1
Caller (C): Hi this is Megan, I’m from Portland Oregon.
Hosts (H): Hi Megan,what’s going on?
C: Well, I have a Honda CRV, it’s a 2003 and when I turn on the air conditioner, only when I
turn on the air conditioner and turn left, the car makes this funny sound, and I thought for
the longest time it was my water bottle tipping over and making this fizzy sound. But my
water bottle’s not in the car any more, and when I turn left, it still does it, and the sound is
like ..
H: We’re ready to have you make the sound.
C: OK. Caller makes the sound.
H: How long do you have to be driving? Does it come on your first left hand turn of the day
or does it have to be after many minutes of driving?
C: Oh, it can be when I right pull out of the driveway and take my first left turn, but it has to
be with the air conditioner on, which in Portland in a month from now, it won’t be a problem
at all.
H: OK, call us back in a couple of weeks and we’ll see what we can do.
H: So it has this sound – it only happens on a left hand turn and only in your 03 CRV. Have
you noticed this in any other vehicle? And it can happen right at the beginning of your trip.
C: If my air conditioner is on.
H: So if you were taking an extended left hand turn, for example, an entrance ramp on a
highway or some such thing, does it do it the whole time you have the wheel turned?
C: Yes.
H: It does!
C: If I go really slow around a corner, it doesn’t make the sound.
H: Ah! Will it even do it if you’re not making a left hand turn per se, but you’re going on a
highway and the roads turns to the left, will it do it then? And is it more likely to do it at
higher speeds?
C: At higher speeds and it has to be a fairly big curve to the left.
H: A fairly sharp curve, you mean.
IM Exercise 4.7
C: Yes.
H: A fairly sharp curve to the left. And you’ve been paying attention to this for how long now?
Since the air conditioning season began?
C: Since it got warm here.
H: Since it got warm. So that’s like in June.
C: No, a month ago.
H: So it’s been doing this for one month or so. I cannot think for the life of me, what it is that
would cause the thing to make a noise when you turn left with the air conditioner on. My
original feeling was that somehow that one of the blend doors … Does the noise sound like
it’s coming from inside the car?
C: Yes.
H: It does!
C: It sounds underneath the glovebox.
H: I think what’s happening is when the air conditioner is on, there’s a door that has to close,
and that door shuts off the flow of air from what’s called the heater core into the passenger
compartment and allows the cold air from the evaporator to enter the passenger
compartment. And I think what’s happening is that door must be weak, and if I’m not
mistaken, I think that might be operated electrically in this car, and it’s trying to close. And
centrifugal force is somehow …. various unimportant banter between hosts … I’m going to
suggest that if we to take a hard turn, a hard sharp turn, it would be at its worst.
C: Yes.
H: So I think what’s wrong is that your blend door for the AC is malfunctioning because the
mechanism is weak, and I would go further (or farther) to say that if you were to drive around
in a circle that consisted of driving to the left, your air conditioner would stop working.
Because I think it would open the door, or at least the effect of the air conditioner would be
negated, because it would opening the door and letting some of the arm air in. Just a guess.
C: So only go in circle to the right.
H: Yes, if you’re going to go in circles, make sure you turn to the right, I think you’ll be
alright. But I think that’s what it is. You can verify this by taking it to your repair shop and
seeing if they can look at the operation of your blend door.
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IM Exercise 4.7
Extract 2
C: Hi, this Nicole callking from Maui, Hawaii.
H: Hi, Nicole, how are you?
C: Hi, Nicole. Maui hey? Whenever people call from Hawaii, my brother gets this glazed look
in his eyes. I’m sure the weather is beautiful there, but it is equally beautiful here. So what’s
up, Nicole?
C: I have a 1995 VW Cabrio and I have a problem with it every time it rains really heavily.
H: It leaks?
C: No, it doesn’t leak, it’s a great car, other than I’ll be driving along and all of a sudden,. it
will start to do a little stuttering. It only does it in a heavy downpour, so I don’t know if it’s
something electrical, or maybe something in the exhaust but I’ll be driving along and it’ll
stutter. It’s never died on me, but it does it periodically, and it’ll do it all the way from here to
the other side of the island.
H: And then if you continue to drive it even though it’s raining, does it eventually clear up or
does it persist the entire time you are driving it?
C: If it’s downpouring, it’ll persist the entire time, but if it clears up, it’s great.
H: So how often does it rain on Maui?
C: Lately, it’s been raining a lot.
H: Really. I told you we did a good thing not going there this year.
C: We out of our rainy season, but we’re heading back into it, and it’s been a bit heavier than
usual.
H: I don’t think there’s any question that you have bad spark plug wires or a bad coil. And the
way you figure this out is the next time it’s raining and running badly, you’re going to get out
of the car,
C: In my raincoat.
H: You’re going to have a raincoat and umbrella, you’re going to open the hood and
preferably you’re going to do this it night. And when you open the hood with the engine
running, you’re going to look and you’re going to see a veritable light show. You’re going to
see sparks jumping all over the place and make note of where those sparks are flying because
that will tell you what’s wrong.
If you see sparks right near the engine where the spark plus are, there are four wires that
connect to these spark plugs. If you see sparks jumping there, it’s probably just spark plug
wires that you need. If instead you see, there’s a single wire that runs form something called
the coil which is up by the firewall, if you see sparks jumping round at the coil, you could
easily need a new coil. because tiny little cracks in what’s called the coil tower will also
become conductive paths for electricity when it’s damp out. Then of course when it dries up,
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IM Exercise 4.7
everything’s fine. But the moisture is causing the problem because the electricity is using the
moisture as a conductive path because any cracks or breaches in the insulation cause the
problem. And any time you don’t get full spark to the spark plugs, the engine stumbles and
misses and jumps and stutters and hesitates, and that’s what you’re getting.
C: That’s good to know. Now I can pass it on to a mechanic … He’ll be impressed with my
knowledge.
H: You could actually do this yourself, Nicole.
C: Can I? OK.
H: You can go to Volkswagen of Maui.
C: Well, there is no Volkswagen of Maui any more. That’s part of the problem.
H: Well, are there any parts stores on Maui?
C: Yes.
H: Go to Pep Boys, and buy a set of spark plug wires for your 95 Cabrio. And then when you
go to replace them, make sure do them one at a time. Take off one old one, put on one new
one, because if you take them all off, you’ll spend a month trying to figure out where they go.
And I’m sure that’s going to fix it.
C: Thank you so much.
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