GMC 1998 Savana Van Owner's Manual page 265

Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine cooling system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
When you replace your thermostat,
an
AC@ thermostat
is recommended.
Power Steering Fluid
When to Check Power Steering Fluid
It is not necessary to regularly check power steering
fluid unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired.
How To Check Power Steering Fluid
When the engine compartment is cool, wipe the cap
and the top of the reservoir clean, then unscrew the
cap and wipe the dipstick with a clean rag. Replace
the cap and completely tighten it. Then remove the
cap again and look at the fluid level on the dipstick.
The level should be at the FULL COLD mark. If
necessary, add only enough fluid to bring the level up
to the mark.
To prevent contamination of brake fluid, never check or
fill the power steering reservoir with the brake master
cylinder cover off.
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