2006 chevy uplander overheating already replaced thermostat when heater core gets hot the heat inside van goes cold

SOURCE: replace heater core 1994 chevy g20 conversion van

Here a are the instuctions to remove it. I did not know if you have A/C or not so I included both for you.

REMOVAL & INSTALLATION
Without Air Conditioning
ALL MODELS
See Figure 1

1. Disconnect the negative battery cable.
2. Remove the coolant recovery bottle.
3. Place a pan under the van and disconnect the heater intake and outlet hoses. Quickly remove and plug the hoses and support them in an upright position. Drain the coolant from the heater core into the pan.

1. Remove the heater distributor duct-to-case attaching screws and the duct-to-engine cover screw. Remove the duct.
2. Remove the engine cover.
3. Remove all the instrument panel attaching screws.
4. Carefully lower the steering column. Raise and support the right side of the instrument panel. Refer to for further details.
5. Remove the defroster duct-to-case attaching screws and the two screws attaching the distributor to the heater case.
6. Disconnect the temperature door cable. Carefully fold the cable back and out of the way.
7. Remove the three nuts from the engine compartment side of the distributor case and the screw from the passenger compartment side.
8. Remove the heater case and core assembly.
9. Remove the core retaining straps and remove the core.

1. Install the core.
2. Install the core retaining straps.
3. Install the heater case and core assembly.
4. Fasten the three nuts on the engine compartment side of the distributor case and the screw on the passenger compartment side.
5. Connect the temperature door cable.
6. Install the defroster duct-to-case attaching screws and the two screws attaching the distributor to the heater case.
7. Install the steering column.
8. Fasten all the instrument panel attaching screws.
9. Install the engine cover.
10. Install the duct. Install the heater distributor duct-to-case attaching screws and the duct-to-engine cover screw.
11. Connect the heater intake and outlet hoses.
12. Fill the cooling system.
13. Install the coolant recovery bottle.
14. Connect the negative battery cable.

1. Disconnect the battery ground cable.
2. Remove the engine cover.
3. Remove the steering column-to-instrument panel bolts. Lower the column carefully.
4. Remove the upper and lower instrument panel attaching screws. Remove the radio support bracket screw.
5. Raise and support the right side of the instrument panel.
6. Remove the lower right instrument panel bracket.
7. Remove the vacuum actuator from the kick panel.
8. Disconnect the temperature cable and vacuum hoses at the case. Remove the heater distributor duct from over the engine hump.
9. Remove the two defroster duct-to-firewall attaching screws below the windshield.
10. Under the hood, disconnect and plug the heater hoses at the firewall.
11. Remove the three nuts and one screw (inside) holding the heater case to the firewall.
12. Remove the case from the van. Remove the gasket for access to the screws holding the case together. Remove the temperature cable support bracket. Remove the screws and separate the case. Remove the heater core.

1. Install the heater core.
2. Assemble the case and fasten the screws.
3. Install the temperature cable support bracket.
4. Position the gasket, then install the case in the van.
5. Fasten the three nuts and one screw (inside) holding the heater case to the firewall.
6. Connect and plug the heater hoses at the firewall.
7. Fasten the two defroster duct-to-firewall attaching screws below the windshield.
8. Install the heater distributor duct.
9. Connect the temperature cable and vacuum hoses at the case.
10. Install the vacuum actuator at the kick panel.
11. Install the lower right instrument panel bracket.
12. Fasten the radio support bracket screw.
13. Fasten the upper and lower instrument panel attaching screws.
14. Fasten the steering column-to-instrument panel bolts.
15. Install the engine cover.
16. Connect the battery ground cable.
17. Refill the cooling system as necessary.

SOURCE: No Heat and Overheating in 1999 Chevy Silverado

After replacing the thermostat, you must bleed the air from the cooling system.

To bleed air from the 2.2L and 2.5L engines, remove the plug or sensor on the top of the thermostat housing. Fill the radiator with coolant until the coolant comes out the hole. Since the plug is made out of steel and the thermostat housing is aluminum, it is a good idea to apply an anti-seizing compound or Teflon® tape on the plug threads prior to installation. Install the plug and continue to fill the radiator. This will vent all trapped air from the engine.

Any trapped air in the heating system will have to be displaced by coolant. Once the cooling system is filled, with the radiator cap off, turn of the heater at it's highest setting. Start the engine and allow it to reach operating temp. You should see a drop in the coolant level as the air in the heating system is displaced by coolant. Add coolant to the proper level and replace the radiator cap.

Keep a close eye on the coolant level for at least the next couple of weeks. The cooling system is a "closed" system. Any significant decrease in coolant level indicates a problem.

If you have any questions, let me know.

Please take the time to rate this solution.

Drive safe and be warm.

clarkco

SOURCE: 1992 Chevy S10 has no heat, Radiator is full of

please change your thermostat,I hope that help you it sounds like it stuck open

Eric

• 25 Answers
• Posted on Dec 08, 2009

SOURCE: chevy astro van heater blowes only cold air

the problem is probably the heater core, it can become clogged with dribris. this stops heat from the engine getting to it and then no heat.

Clifford Beard

• 1975 Answers
• Posted on May 01, 2011

SOURCE: Firing ORDER FOR THE 2006 chevy Uplander Van 6

There are 2 6 cylinder engines for that year. Both are the same as far as wiring/firing order but gave you both anyway(see below). There have been times that I thought I did the same thing as far as the firing order and have been doing it for 25+ years. Sometime i did and sometimes I didn't. So if you find the wiring is correct and you seem to have a miss, In about 90 percent of the time that this has happened to me I had knock a vacuum hose off so you might want to start there if they are right. It sure sounded like a miss at those times but was vacuum. There are other factors but that's where I would start if this is the case. I hope this helps and good luck.