How to save $350.00 + (Thermostat Replacement 2.4L - P0128) - Chevy HHR Network

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Old 07-10-2009, 02:21 PM   #1
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How to save $350.00 + (Thermostat Replacement 2.4L - P0128)

...well, minus your actual cost on parts.

*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.

Last edited by Smoke Wagon; 07-10-2009 at 02:29 PM. Reason: spelling
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Old 07-12-2009, 01:11 PM   #2
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Thanks for the (easy read) write up Smoke!
I'm sure I'll be doing this at some point.

Just curious, how many miles are on your odometer?
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Old 07-13-2009, 10:22 AM   #3
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81k and change.
Mild climate(a few nights below freezing by a couple degrees in winter), and rarely over 95 degrees in summer.

always warmed up, never had a cooling issue, and I rarely use the A/C.
I just commute in it...60 miles each way-no traffic at all in one direction, maybe 30% traffic in the other, so it actually has a pretty easy "freeway" lifestyle.

The part just failed.
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Old 07-13-2009, 10:56 AM   #4
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Glad to see it's an easy repair. The 2.2 and the 2.0 "should" be the same.

There is no lifetime on a stat, it works until it don't work no more.....
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Old 09-27-2009, 08:49 AM   #5
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Thank you!!!

Hello Smoke Wagon

Thank you very much for posting this information. I bought a 2006 Chev HHR 2LT about two weeks ago, and I was a little disappointed to run into the "CEL and --- Coolent" issue within 48 hours of owning the car. Needless to say, I got a $377 (CA) repair estimate from our local GM dealership as I bought the car as-is from them.

Living in Canada, I didn't couldn't find a parts store that sold AC Delco parts, but I found the MotoRAD thermostat sold at Canadian Tire seems to do the trick. Instructions mentioned that it take about 30 minutes to repair, and for a person that has no mechanical inclianation, I had changed my thermostat myself in 1 hour. Lots of wires in the way, and tight working area, but once I got the house off, I was done in 10 minutes..

Parts Used:
1 Gallon - Prestone PreMix Dex Cool (I know, I know) - $16.99 (Canadian Tire)
1 MotoRAD 180 degree Thermostat. = $30.99 (Canadian Tire)

The repair cost me just about $60 with tax's, and an hour of time to install. It's been two days now, and no CEL, and coolant steadies at 95 degrees celius while highway driving.. I now get to enjoy my car..

Thank you again for everyone help..
I love forums!

Frenchy - '06 HHR 2LT - 2.4 Auto - Chrome and leather, mmmmm...

Last edited by frenchy128; 09-27-2009 at 08:57 AM. Reason: correction on model type... 2LT not 1LT..
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Old 09-27-2009, 05:28 PM   #6
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Just one quick note....
Before you start, open the rear, pull the floor and the inner floor.
Pull the fuse near the battery.
Now change the stat as described....
Put the fuse back in, then start the car.
Pulling the fuse for the couple of minutes it takes to change the stat will clear out your codes, and your good to go.

No need for a trip to the auto parts store......
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Old 09-27-2009, 10:18 PM   #7
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Good detailed info & pic. Thanks all...
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Old 09-29-2009, 01:31 PM   #8
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HHorange...the CEL goes out on its own. I am sure the code is stored in memory for retrieval...but once the PCM detects normal heat cycle, the light does not come back on.

my didnt. I did the change and as soon as i was done, I turned the key on, started the engine to check for leaks, and no CEL.
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Old 01-16-2010, 11:41 AM   #9
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On other threads some said the thermostat they installed did not work. When I replaced mine this week it was not opening at first. I thought that I might have an air bubble in the thermostat. So with the fill cap off I squeezed the hose going to the thermostat and worked the air out of the line. Every time the coolant level dropped I topped it off until I worked all of the air out . I started up the car let it warm up and the thermostat opened.
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Old 08-09-2010, 04:10 PM   #10
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OK, I just had the same issue with mine. It's an 07 with 50500 miles. This is where I found out what was wrong with it, and I used these instruction on how to fix it. Here's my question. When I refilled the coolant and let it sit idling with my girlfriend watching the temp, it wouldn't get above 173. Anyway, I filled it several times and squeezed the lower radiator hose, and refilled. It didn't take the whole gallon, I would say there is about 1/4 of a quart left in it. I replaced the cap, and drove it for about 5 miles. The temp responded as it always had, somewhere around 190's, with a top of 203 after hard acceleration. I'm letting it cool down now to recheck, but does all that sound right, how much went back in. I want to make sure I don't have any air pockets. and by the way, when I drained the coolant, all I did was roll it up on some ramps, and unscrew the plug in the radiator. so what ever amount that will come out from the, and the little spillage from undoing the thermostat house is all that was removed.
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