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| Other
typical orifice tubes used in today's vehicles |
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| The
GM Black/White tube is typically located at the condenser outlet. Notice
that the 'Tabs' for removing this tube are on the OUTLET side of the orifice
tube. Therefore, the refrigerant flow enters from the black end (with inlet
filter screen) and exits through the white end. |
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| The
most noticeable difference with the Ford orifice tubes it that they use a
redundant seal; there are 2 o-rings to seal the high pressure side from
the low pressure side. |
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| The
different orifice tube colors represent various sizes of the actual orifice
(brass internal section). Although they only vary by a few thousandths of
an inch, that's enough to change the flow rate of the refrigerant. Typically,
for maximum performance of the A/C system, the orifice tube opening is matched
to the system by the vehicle manufacturer. |
|
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| Although
they were designed for specific applications, many technicians will interchange
orifice tubes using slightly smaller diameter orifice than originally specified
by the vehicle manufacturer. The intention is to get a lower pressure on
the low side of the system, therefore resulting in a lower evaporator
temperature. |
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| Like
Ford designed orifice tubes, Chrysler's Purple orifice tube incorporates
two o-rings sealing the high pressure from the low pressure side. |
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| A
Close up look at the Orifice Tubes: |
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What's
wrong with these orifice tubes?
How can you help prevent this? |
 |
Orifice
tubes can easily become restricted with debris that may travel through the
system. Restricting the orifice tube immediately restricts the flow of
refrigerant. It also limits the flow of refrigerant oil. The oil is required
to maintain compressor lubrication. Therefore, orifice tube restrictions
can easily cause a catastrophic compressor failure. |
 |
What
causes the debris and contamination? In short, moisture which enters the
system mixes with the refrigerant to form acids. Those acids corrode aluminum
components. That corrosion moves throughout the system and get caught by
the filter screens on the orifice tube. As shown on the left, if takes less
than 1/10 of a teaspoon of debris to plug the orifice tube. |
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How
can you prevent this from happening?
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Get your
free copy of the
A/C
Connection!™ |
|
It's your 'one
click' direct connection
to auto A/C Help, Information
and Parts Sources |
|
Your A/C
Connection!™ is the best
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This was probably one of the best books on recharging
air conditioning that I have seen...