Heater - Poor Performance
90nissan05Classification: Section: HEATER AND
HA90-012 AIR CONDITIONER
Reference:
TECHNICAL BULLETIN NTB90-079
Models:
1989 & 1990 J30 Date:
SEPTEMBER 27, 1990
POOR HEATER PERFORMANCECOOLANT BLEEDING PROCEDURE
(REVISED)
This Bulletin Supersedes Bulletin TS89-161 (EM89-009) dated December 14, 1989
APPLIED MODEL: 1989 & 1990 Maxima (J30)
SERVICE INFORMATION:
Some 1989 and 1990 maxima vehicles may exhibit poor heater performance. A customer may complain that, "the heater takes too long to produce any heat ... once the heater starts working, it provides adequate heat." This incident occurs because air bubbles have become trapped in the heater core. A new cooling system bleeding procedure, which differs from the earlier published procedure (EM89-009/TS89-161), has been developed to resolve this complaint.
Nissan recommends engine coolant change every two (2) years or 30,000 miles under normal use. This procedure should be used whenever coolant is changed.
BLEEDING PROCEDURE:
1. Lift only the front end of the vehicle, so that the bottom edge of the front bumper fascia is about 990 mm (39") above the ground. Make sure that the exhaust finisher is not damaged by contact with the ground.
[Raising the front end of the vehicle lowers the heater core location below the radiator inlet opening.]
NOTE: If starting with an empty heater system (no coolant), the system should be filled with coolant with the front end already raised.
2. Make sure the engine is cool. Remove the radiator cap and add coolant as required so that the coolant level comes up to the radiator filler opening.
3. Turn the engine ON and run it at ldle.
4. Move the temperature control lever to the "full hot" position on vehicles equipped with a manually-controlled air conditioning system or 85~ Fahrenheit for an automatically-controlled air conditioning system.
5. Select "Foot" mode for vehicles equipped with manually controlled air conditioning systems. Make sure the air conditioner is OFF. Select "FOOT & ECON" mode for vehicles equipped with an automatically controlled air conditioning system.
[If the A/C compressor is left ON, the engine fan runs continuously. This keeps the engine temperature low and does not allow the thermostat to open. Also, if the A/C compressor is left OFF, the engine fan will come ON when the thermostat opens.]
6. Increase the engine speed to about 1500 RPM and hold. Decrease the engine speed if there is excess coolant spillage from the radiator inlet opening. Place a small object (e.g. a folded piece of paper) between the throttle drum stopper and the intake manifold to hold the engine speed.
7. Watch for air bubbles coming out of the radiator inlet opening to make sure the air bubbles are being purged. Add coolant as necessary to maintain a full radiator. The coolant level, as seen at the radiator inlet opening, will drop when the thermostat opens. Do not add coolant when the thermostat is opened as the radiator will overflow when the thermostat closes. When the engine fan is running it is a good indication that the thermostat is in the "open" position. This procedure must be run for at least 30 minutes or until large air bubbles (larger than 5 mm diameter) stop comming out to ensure that all air bubbles are purged from the cooling system. This usually requires the thermostat to open on two separate occasions.
8. After 30 minutes, there still may be tiny bubbles (less than 5 mm diameter) coming from the radiator filler opening. It is normal for bubbles of this size to continue, so, it is not necessary to continue the procedure until the small bubbles stop.
9. After the bleeding procedure is complete, remove the small object inserted between the throttle drum stopper and the intake manifold and return the engine to idle. Add coolant to fill the radiator and immediatelv place the cap back on the radiator.
10. Slowly lower the front of the vehicle to the ground.
11. Add coolant to the reservoir tank until the level reaches the "MAX" mark. Remove the screw which secures the coolant reservoir tank, and with the return tube attached, lift the reservoir tank above the radiator. Tilt the reservoir tank so the return tube is at the lowest point. Squeeze the return tube to purge the air trapped in the tube. When the return tube is filled with coolant, return the reservoir tank to its proper location.
12. Shut the engine OFF. The engine should be allowed to cool down. If the system is not completely filled, some coolant will be sucked back into the engine. Additionally, the procedure should be repeated at least once to ensure that all of the air has been bled out of the system.