Thermastat - 1999 Nissan Quest

When refilling, make sure that you do not rush the filling - pour the coolant slowly so that the air gets out. Had that problem and trapped air in the system. Would drive vehicle for 300 miles at 70mph and engine is still very cold with no heat....had to release the bleeder screw and rev the engine to get out the air. Bleeder screw is located on the upper of the engine shown on the manual. Dealer wanted $350.00 to bleed it. Takes about 2 hours, so be safe and don't rush and fill the coolant - pour slowly.

My 1999 Nissan Quest blows cold air instead of hot when the heater is turned on

Removal & Installation
CAUTION Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Drain the radiator and recycle the engine coolant.
   
2. Remove the upper radiator hose bracket bolt and remove the bracket.
   
3. On 1993–98 3.0L engine models:
   
   • Remove the bolt from the A/C high pressure line bracket at the front of the engine.
     
   • Remove the two A/C accumulator/drier bracket bolts.
     
   • Position the accumulator/drier and A/C line out of the way.
     
4. Remove the bypass hose clamp and remove the hose from the water inlet.
   
5. Remove the four water inlet bolts and remove the inlet.
   
6. Remove the thermostat from the inlet.
   

1. Clean and dry the water inlet and thermostat housing mating surfaces.
   
2. Apply a continuous bead of RTV silicone sealant 0.08–0.12 inch (2.0–3.0mm) wide to the water inlet mating surface.
   
   NOTE The water inlet must be installed within 5 minutes of applying the sealant.
   
   
3. Install the thermostat in the water inlet, with the jiggle valve at the topmost (12 o’clock) position.
   
4. Install the water inlet to the thermostat housing. Install the bolts and tighten them to 12–15 ft. lbs. (16–21 Nm).
   
5. Install the bypass hose to the water inlet, using a new clamp.
   
6. On 1993–98 3.0L engine models:
   
   • Install the accumulator/drier and tighten the bracket bolts to 45 inch lbs. (5 Nm).
     
   • Install the A/C high pressure line bracket and tighten the bolt to 45 inch lbs. (5 Nm).
     
   • Install the upper radiator hose bracket and tighten the bolt to 34–48 ft. lbs. (46–65 Nm).
     
     NOTE Allow the sealant to dry for at least 30 minutes before adding coolant.
     
     
7. Fill the cooling system. Run the engine and check for leaks.