Heater core?

Hello,

Start by disconnecting the battery and you will need to vacuum the AC system and drain the coolant out. Here is a guide that will help and the instructions for doing the job are in the diagrams below.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

and this is an older truck but you get the idea, check the diagrams below to replace the heater core in your truck.

https://www.2carpros.com/articles/replace-heater-core

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Symptoms fit a heat core not a head gasket.

The film on the window is probably the anti-freeze from a slow leak in the core. IF the core is not staying full, there will be no heat.

Do you know where the coolant leak is you mentioned?

It could be a thermostat or the heater core is plugged and needs prestones super flush. This is the only flushing kit I found that works for the blazer heater core

Hello,

You can try flushing with water, from the no water side, and see if can flush it out.

And of course if can't then will need to replace.

.

REMOVAL:
Remove the HVAC module-auxiliary.
Remove the screws from heater core cover-auxiliary from the HVAC module-auxiliary.
Remove the heater core cover-auxiliary.
Remove the HVAC module pass thru seal-auxiliary.
Remove the heater core-auxiliary from the HVAC module-auxiliary.

INSTALLATION:
Install the heater core-auxiliary to the HVAC module-auxiliary.
Install the HVAC module pass thru seal-auxiliary.
Install the heater core access cover-auxiliary to the HVAC module-auxiliary.
Install the screws to the heater core access cover-auxiliary and tighten to 18 inch lbs. (2 Nm).
Install the HVAC module-auxiliary.

HVAC MODULE REMOVAL/INSTALLATION:
Recover the refrigerant.
Drain the cooling system.
Raise and support the vehicle.
Remove the nuts from rear A/C line block fittings.
NOTE
Cap or tape the open A/C refrigerant lines immediately.

Remove the A/C line block fittings and discard the O-ring seals.
Remove the nuts from the heater hoses block fittings.
Remove the heater hoses block fittings from the HVAC module-auxiliary.
Remove the nuts from the HVAC module studs.
Lower the vehicle.
Remove the right side rear quarter trim.
Disconnect the electrical connectors from the HVAC module.
Disconnect the rear compartment air outlet ducts from the HVAC module.
Remove the mounting bolts from the HVAC module.
Remove the HVAC module.
Remove and discard the HVAC module pass through seal.

To install:
Install new HVAC module pass through seal.
Install the HVAC module.
Install the HVAC module mounting bolts and tighten to 89 inch lbs. (10 Nm).
Install the air outlet ducts.
Connect the electrical connectors.
Install the right side rear quarter trim panel.
Raise and support the vehicle.
Connect the heater hoses to the heater core.
Install the nuts to the HVAC module studs. Tighten the nuts to 89 inch lbs. (10 Nm).
Remove the cap or tape from the A/C lines.
Install the new O-ring seals.
Install the nuts to the evaporator core studs and tighten to 15 ft. Lbs. (20 Nm).
Lower the vehicle.
Fill the cooling system.
Evacuate and charge the system.
Leak test the fitting of the component.

Thanks for using 2CarPros. Com!

May be faulty heater core hose that is leaking outside of cab so no coolant getting into floorboard. If coolant is found leaking around core then either hoses or core is faulty.

Take it back and have them check to see if all the actuators are working, bet they aren't. Probably forgot to hook it up or not all the way so it won't work.

That doesnt matter. Unless you have a heater control valve and thats on the intake line.

But if you really want to know you can find th ehotter hose and that will be the intake to the heater core.

It is simpler to bypass it but then heater would not work. Is best just to replace so it will work properly.