Sixty7camaro

Thought I had a bad servo to the door that mixes temp. Turns out the servo is good. The shaft that the servo rotates is broken off! Looks like it has been "repaired" in the past as there is glue residue on the broken remnants and there are pieces of the shaft missing. Dealer estimate to repair is $900 but would likely be a couple hundred more as "They wouldn't look forward to performing this repair". Any thoughts or experience with this issue? The purchase of this Cobalt has been a mistake from day one.

oldchevy

They probably have to remove the dash to do it properly. If this is not a daily driver, then you can do it yourself. Take your time and do it as time permits.

Sixty7camaro

No way was I going to pay the local dealer $1200 to replace a $16 blend door. I looked through my junk and found a brass bushing I'd machined for another project and it happened to be the correct i.d. to fit the door shaft. I epoxied the shaft back together using the bushing as a coupling. I also had to trim the white blending cam for the upper servo to clear the bushing. Not very much, just a little on the bench grinder. I'd post pictures but I cannot seem to upload them. It was a major pain to do this as I was on my head fitting it all together. However, it works and it cost about ten bucks.

dougtex28

I fixed mine using a piece of 1/2" copper pipe from Lowe's ($6) to make a sleeve for it. I had to buy a 2 foot piece because I could not find a smaller piece. You have to be sure to buy the actual pipe, not one of the couplings because the inside diameter is larger on couplings. I took the end of the plastic shaft that was broken off with me to make sure it fit. I then just purchased some epoxy (also at Lowe's in the paint/caulk section). The key is to make sure that you line up the piece that broke off with the other side of the shaft, it was easy for me because it was not a clean break, it was more of a diagonal break making it clear how it was supposed to line up.

The reason alignment matters between the broken pieces is because it can impact how the servo and blend door align. The servo position is set by the temperature dial and the blend door needs to correspond to the dial setting (hot position vs cold position and everything in between), improper alignment could also cause it to break again since there are mechanical limits on blend door movement. If you are not to tell how it goes back together, you can manually flip the door to either "full hot" or "full cold", then set the temperature dial to match and make sure the end of the shaft will fit into the servo opening (it is keyed).

I hope this helps. I worked out great for me and only took about 10 minutes.

Ann Wilson-Mcnally

The blend door is under the dash and you can see the box where the blend door and actuator are located, between the driver and passenger foot wells.

I removed the blend door actuator to find that the post on the blend door is totally sheared off. There is not even anything that I could even try and hook into.

As such, it appears that I will have to get in there and totally replace the blend door.

First issue is, I cannot find a blend door at local parts places, so I may have to go to a dealer to get it.

Second, I have been unable to find anything that explains how to replace that type of blend door. I can find the one that is behind the glove box, but not the one that is down between the driver and passenger foot wells, at the very bottom of the dash.

If anyone knows of a source of information on how to do this, I would greatly appreciate it.

iggy13

You wrote that the repair took 10 minutes. Did this include taking the dashboard out? I can't see anyway to fix it unless I remove the dashboard.

Please let me know.

dougtex28

I did not have to take out the dash. The actuator is accessible from the driver side floorboard. You have to get your head down near the pedals then look towards the passenger side and you should see the actuator. I no longer have this car so I can't take any pictures, but remember that it was easy to locate and remove. The actuator should be good, it is the blend door shaft, which the actuator rotates, that is likely broken. Take the broken piece with you to fit test with the pipe you will buy to sleeve it. If it turns out the blend door shaft is completely sheared off, then this "easy" repair will not work for you and the dash will have to come out to replace the blend door. You will know for sure once you remove the actuator. Good luck!!

tech2

very clever repair.


gm engineering has done a similar type of repair on the 2006 equinox. if may work on the cobalt. they sell a sleeve that is made to slide over the broken blend door and fit into the actuator splines. the sleeve is around $10 and installation requires making a cut in the hvac box with a hole saw tool. the sleeve works better than a new door as it stops the over cinching of the door which breaks the shaft. repair time is 1 hour if the door has not fallen into the hvac box. 3hrs if its fallen into the box.


other repair methods such as blend door replacement is probably a 6-8 hour job

Silverio Hernandez

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Hey I was wondering how do I change it from full hot to full cold on my 2008 Chevy Cobalt LT manually. Thank you