I was wondering if you have a blowup of how to replace front heater core of a 88 Suburban?

 here it is some info.

If yours is not in here let me know...no diagrams available from me right now.

Rear

1988-91 Models

1. 
   

   Disconnect the negative battery cable.

   
   
2. 
   

   Drain the cooling system.

   
   
3. 
   

   Disconnect the heater hoses at the core tubes.

   
   
4. 
   

   Disconnect the blower motor wiring harness.

   
   
5. 
   

   Remove the blower motor clamp.

   
   
6. 
   

   Remove the motor attaching screws and lift out the motor.

   
   
7. 
   

   Unfasten the upper-to-lower case half screws and remove the upper case half.

   
   
8. 
   

   Remove the core seal.

   
   
9. 
   

   Lift out the core.

To install:

1. 
   

   Install the heater core.

   
   
2. 
   

   Install the core seal.

   
   
3. 
   

   Install the upper case half and then tighten the upper-to-lower case half screws.

   
   
4. 
   

   Install the motor and then tighten the attaching screws.

   
   
5. 
   

   Install the blower motor clamp.

   
   
6. 
   

   Connect the blower motor wiring harness.

   
   
7. 
   

   Connect the heater hoses at the core tubes.

   
   
8. 
   

   Fill the cooling system.

   
   
9. 
   

   Connect the negative battery cable.  

1988-90 C/K Series

1. 
   

   Disconnect the negative battery cable.

   
   
2. 
   

   Remove the coolant overflow bottle.

   
   
3. 
   

   Drain the cooling system.

   
   
4. 
   

   Disconnect the heater hoses at the core tubes.

   
   
5. 
   

   In the engine compartment, remove the heater case-to-firewall screws.

   
   
6. 
   

   Disconnect the antenna cable at the mast.

   
   
7. 
   

   Remove the glove box.

   
   
8. 
   

   Disconnect the wiring harness at the engine's Electronic Control Module (ECM).

   
   
9. 
   

   Remove the ECM and bracket.

   
   
10. 
    

    Remove the right side kick panel.

    
    
11. 
    

    Remove the right side lower dash panel bolt and nut.

    
    
12. 
    

    Remove the heater case mounting bolts.

    
    
13. 
    

    While lifting the instrument panel slightly, remove the case assembly.

    
    
14. 
    

    Lift the core from the case.

To install:

1. 
   

   Lower the core into the case.

   
   
2. 
   

   Position the case assembly against the firewall.

   
   
3. 
   

   Install the heater case mounting bolts.

   
   
4. 
   

   Install the right side lower dash panel bolt and nut.

   
   
5. 
   

   Install the right side kick panel.

   
   
6. 
   

   Install the ECM and bracket.

   
   
7. 
   

   Connect the ECM wiring harness.

   
   
8. 
   

   Install the glove box.

   
   
9. 
   

   Connect the antenna cable at the mast.

   
   
10. 
    

    Install the heater case-to-firewall screws.

    
    
11. 
    

    Connect the heater hoses at the core tubes.

    
    
12. 
    

    Fill the cooling system.

    
    
13. 
    

    Install the coolant overflow bottle.

    
    
14. 
    

    Connect the battery cable.

Front

1988-91 R/V Series WITHOUT AIR CONDITIONING

1. 
   

   Disconnect the negative battery cable.

   
   
2. 
   

   Disconnect the heater hoses at the core tubes and drain the engine coolant. Plug the core tubes to prevent spillage.

   
   
3. 
   

   Remove the nuts from the distributor air ducts in the engine compartment.

   
   
4. 
   

   Remove the glove compartment and door.

   
   
5. 
   

   Disconnect the air-defrost and temperature door cables.

   
   
6. 
   

   Remove the floor outlet and unfasten the defroster duct-to-heater distributor screw.

   
   
7. 
   

   Remove the heater distributor-to-instrument panel screws. Pull the assembly rearward to gain access to the wiring harness and disconnect the wires attached to the unit.

   
   
8. 
   

   Remove the heater distributor from the truck.

   
   
9. 
   

   Remove the heater core retaining straps and remove the core from the truck.

To install:

1. 
   

   Install the heater core. Be sure that the case-to-core and case-to-dash panel sealer is intact.

   
   
2. 
   

   Position the heater distributor. Connect the wires attached to it and then install the heater distributor-to-instrument panel screws.

   
   
3. 
   

   Install the floor outlet and tighten the defroster duct-to-heater distributor screw.

   
   
4. 
   

   Connect the air-defrost and temperature door cables.

   
   
5. 
   

   Install the glove compartment and door.

   
   
6. 
   

   Install the nuts into the distributor air ducts (in the engine compartment).

   
   
7. 
   

   Connect the heater hoses at the core tubes.

   
   
8. 
   

   Connect the negative battery cable. Fill the cooling system and check for leaks.

1988-91 R/V Series WITH AIR CONDITIONING

1. 
   

   Disconnect the negative battery cable.

   
   
2. 
   

   Disconnect the heater hoses at the core tubes and drain the engine coolant. Plug the core tubes to prevent spillage.

   
   
3. 
   

   Remove the glove compartment and door.

   
   
4. 
   

   Disconnect the center duct from the defroster outlet duct.

   
   
5. 
   

   Disconnect the center, lower air distributor and the center air outlet ducts.

   
   
6. 
   

   Disconnect the temperature door cable.

   
   
7. 
   

   Remove the nuts from the 3 selector duct studs that project into the engine compartment.

   
   
8. 
   

   Remove the outlet duct-to-instrument panel screws. Pull the assembly rearward to gain access to the wiring harness and disconnect the wires and vacuum tubes attached to the unit.

   
   
9. 
   

   Remove the heater distributor from the truck.

   
   
10. 
    

    Remove the heater core retaining straps and remove the core from the case.

To install:

1. 
   

   Install the heater core. Be sure that the core-to-core and case-to-dash panel sealer is intact.

   
   
2. 
   

   Position the heater distributor. Connect the wires attached to it and then install the heater distributor-to-instrument panel screws.

   
   
3. 
   

   Install the floor outlet and tighten the defroster duct-to-heater distributor screw.

   
   
4. 
   

   Connect the temperature door cable.

   
   
5. 
   

   Connect the center and lower air distributors and the center air outlet ducts.

   
   
6. 
   

   Connect the center duct to the defroster outlet duct.

   
   
7. 
   

   Install the glove compartment and door.

   
   
8. 
   

   Connect the heater hoses at the core tubes.

   
   
9. 
   

   Connect the negative battery cable. Fill the cooling system and check for leaks.

 i just now see you wanted for front only..sorry