Grand AM V6-181 3.0L (1985)
Coolant: All Technical Service Bulletins
A/C - Heater Performance Reduced By Air In Coolant
Number
85-1-5A
Date
3/85
Subject:
HEATER PERFORMANCE
1985 GRAND AM WITH 3.0L MFI V-6 ENGINE (LN7)
PROPER COOLANT FILL
On the Grand Am, as well as other models, care should be taken to remove any trapped air from the engine cooling system. Air trapped in the heater core
can significantly degrade heater performance and cause heater temperature cycling. To ensure adequate fill and remove trapped air, use the following
procedure:
CAUTION: Use proper precautions to help avoid the danger of being burned when removing or installing radiator cap and when expelling any trapped
air.
1.
Remove radiator cap.If engine is hot, allow it to cool down until radiator cap can be safely removed. Top off coolant in radiator to within 3" of the
top.
2.
Place HVAC controls in A/C mode, or auto on C68, and temperature to highest setting.
3.
Start engine and allow it to warm up while idling until thermostat opens. Coolant level in radiator will rise somewhat when thermostat opens. In
cold ambients, run until radiator core is hot to the touch.
4.
Allow engine to continue idling until lower radiator hose to water pump is hot.
5.
Cycle the engine speed up to about 3000 RPM five times, and back to idle. This should expel any trapped air in the system.
6.
After the air has been expelled, fill the radiator, check the protection level, and install the radiator cap. The fan may not cycle in cold ambients.
7.
Fill coolant overflow reservoir to the hot level. Check for any coolant leaks with engine running.
Coolant bypass from the intake manifold to water pump is being added on the LN7 engine for coolant temperature cycling.
