Chevrolet TrailBlazer, Service Manual

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Do not open a cooling system when the engine is at running temperature. Personal
injury can result.
Kinks in the refrigerant tubing or sharp bends in the refrigerant hose lines will
greatly reduce the capacity of the entire system.
High pressures are produced in the system when it is operating. Extreme care
must be exercised to make sure that all connections are pressure tight. Dirt and
moisture can enter the system when it is opened for repair or replacement of lines
or components. The refrigerant oil will absorb moisture readily out of the air. This
moisture will convert into acids within a closed system.
The system must be completely empty before opening any fitting or connection in
the refrigeration system. Open fittings with caution even after the system has been
emptied. If any pressure is noticed as a fitting is loosened, retighten fitting and
evacuate the system again.
A good rule for the flexible hose lines is to keep the radius of all bends at least 10
times the diameter of the hose. Sharper bends will reduce the flow of refrigerant.
The flexible hose lines should be routed so they are at least
3 in. (80 mm) from the
exhaust manifold. Inspect all flexible hose lines to make sure they are in good
condition and properly routed.
The use of correct wrenches when making connections is very important. Improper
wrenches or improper use of wrenches can damage the fittings.
The internal parts of the A/C system will remain stable as long as moisture-free
refrigerant and refrigerant oil is used. Abnormal amounts of dirt, moisture or air can
upset the chemical stability. This may cause operational troubles or even serious
damage if present in more than very small quantities.
When opening a refrigeration system, have everything you will need to repair the
system ready. This will minimize the amount of time the system must be opened.
Cap or plug all lines and fittings as soon as they are opened. This will help prevent
the entrance of dirt and moisture. All new lines and components should be capped
or sealed until they are ready to be used.
All tools, including the refrigerant dispensing manifold, the manifold gauge set, and
test hoses should be kept clean and dry.
Cleanliness and Care, Shop Practice
It should be understood that proper cleaning and protection of machined surfaces
and friction areas is part of the repair procedure. This is considered standard shop
practice even if not specifically stated.
When any internal engine parts are serviced, care and cleanliness is important.
When components are removed for service, they should be marked, organized or
retained in a specific order for reassembly.
At the time of installation, components should be installed in the same location and
with the same mating surface as when removed.
An automobile engine is a combination of many machined, honed, polished and
lapped surfaces with tolerances that are measured in millimeters or thousandths of
an inch. These surfaces should be covered or protected to avoid component
damage.
A liberal coating of clean engine oil should be applied to friction areas during
assembly.
Proper lubrication will protect and lubricate friction surfaces during initial operation.