...well, minus your actual cost on parts.
THERMOSTAT REPLACEMENT 2.4*
*2.2 may be the same
I have read quotes from people who called the dealer that they charge upwards of around $350 to replace a thermostat in a HHR.
I had the typical flat-lined temp gauge, and a code 128 with a CEL.
I decided to approach the situation, and repair the vehicle myself.
I ordered a Thermostat from NAPA-cost $33.80 in stock
Here's how I replaced mine:
(thanks to rezonatefreak for pictures)
-let engine cool
-use a code scanner to CLEAR the code 128 from the PCM. If you do not have a code scanner, go to Autozone AFTER you have done the following repairs. They pull/clear codes for free.
-open hood, and remove the cooling system fill cap that is located on the passenger side of the radiator's upper hose(near the air filter cover)
-open petc0ck at bottom of radiator on passenger side, and drain coolant in to drain pan.
-locate THERMOSTAT housing on driver's side of engine, just above transmission case. It is almost directly below the oil fill cap
-remove the two 10mm bolts that hold the housing on. You can use a 1/4" drive ratchet, short socket or wobbly 10mm socket, and a 12" extension if available(makes the job easier)
-lift up, and pull the housing towards the radiator, while leaving the hose attached. if you wish to replace the hose clamp, do this now. Inspect underside of housing to be sure there are no remnants of the old o-ring/seal.
-remove the old thermostat. Make note of how it sits in the hole.
-inspect underside of thermostat opening to make sure there are no remaining o-ring particles.
-install new thermostat exactly like the old one was sitting.
-align thermostat housing in to position, and re-install the two 10mm bolts.
-close petc0ck at bottom of radiator.
-fill cooling system through upper hose fill cap opening with coolant of your choice. Most elect to flush out all traces of Dex Cool.
-turn on climate control to FULL HOT, select VENT, and open the vents, and turn the fan on high.
-start the engine. let the engine run until you feel heat coming from the vents. Use your DIC to select COOLANT temperature, and watch it until it reaches 190 degrees. Keep an eye on the coolant level at the fill hole. Once you have HEAT and temperature has reached 190 degrees, top off and close cap. Fill overflow to capacity.
This entire job takes less than 30 minutes if you have the proper tools.
I drove my car on to the rack at 4:45pm yesterday, cleared the code, did the repair, and drove off the rack at 5:05pm.
total cost was $12.00 in anti-freeze, and $34 for the Thermostat. How the dealers can get away with charging over $350 for this job is beyond me. They sell the T-stat for over $50, and I am sure they charge to clear the code as well. But still...if you stood outside and watched them do this repair, they would be finished in 15 minutes total, unless they milk it knowing you're watching. But $350 is just robbing the customers blind.
I've done some major work on many cars before, as well as some easy work. This is as easy as doing a T-stat in a small block Chevy.