Mechanics

HEATING SYSTEM

2003 Cadillac CTS

Heater problem
2003 Cadillac CTS 6 cyl Two Wheel Drive Automatic 76,000 miles

My car does not seem to be throwing heat. The A/C system works, but when I turn the temp up if the A/C is on then it will be only cold air rather than temp adjusted. If the A/C is off, then all I get is luke warm air, regardless if it is 100 degrees outside or 50 degrees. Is there a simple fix for this, or will I have to replace the entire A/C and heater system?

V/r
Frigid to the Bone
Avatar
Wolvieburns01
July 6, 2009.




I sounds like you may simply have a thermostat that is stuck open. What does the engine temperature read, lower than it should?

Factoryjack
Jul 7, 2009.
Yea, that sounds about right. So how do I fix that?

Tiny
Wolvieburns01
Aug 16, 2009.
Remove the upper and lower intake, and perform the following.

Engine Coolant Outlet Pipe Replacement
Tools Required
J 38185 Hose Clamp Pliers

Removal Procedure
Drain the cooling system. Refer to Cooling System Draining and Filling.

Position the J 38185 to the clamp in order to remove the radiator inlet hose (1) from the coolant outlet pipe.

Remove the bolt (2) securing the following to the cylinder head: " The oil level indicator tube (4)

" The coolant outlet pipe (3)

" The engine front lift bracket (1)

Remove the coolant outlet pipe (3) from the thermostat housing.

Remove the O-ring seals from the coolant outlet pipe.
Discard the O-rings.

Installation Procedure

Lubricate 2 new O-ring seals with coolant.
Important: Ensure the O-rings are not twisted.

Install the new O-ring seals around the coolant outlet pipe grooves.

Insert the coolant outlet pipe (3) into the thermostat housing.
Notice: Refer to Fastener Notice in the Preface section.

Install the bolt (2) securing the following to the cylinder head: " The oil level indicator tube (4)

" The coolant outlet pipe (3)

" The engine front lift bracket (1)

Tighten
Tighten the oil level indicator tube bolt to 20 N m (15 lb ft).

Engine Coolant Thermostat Housing Replacement (LA3, LY9)
Removal Procedure
Remove the coolant outlet pipe. Refer to Engine Coolant Outlet Pipe Replacement.
Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical-2.6L and 3.2L.

Remove the thermostat housing bolts (1).
Remove the thermostat housing (2) with thermostat, from the engine.
Remove and discard the seal ring.
Remove the thermostat from the thermostat housing. Refer to Engine Coolant Thermostat Replacement.
Installation Procedure
Install the thermostat into the thermostat housing. Refer to Engine Coolant Thermostat Replacement.

Install a new seal ring.
Position the thermostat housing (2) with thermostat, to the engine.
Notice: Refer to Fastener Notice in the Preface section.

Install the thermostat housing bolts (1).
Tighten
Tighten the thermostat housing bolts to 20 N m (15 lb ft).

Install the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical-2.6L and 3.2L.
Install the coolant outlet pipe. Refer to Engine Coolant Outlet Pipe Replacement.
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Factoryjack
Aug 17, 2009.

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