A/C Question

[UMEXT]

Okay, so thanks to The Roadie I resuscitated my A/C. Now it does a new lovely thing. When I start it, it blows cold just fine. After about half an hour of running, it starts blowing outside air, neither heated nor cooled, and will do that the rest of the day no matter what I do on the dash, and no matter how many times I stop and restart. It's August in Florida. Any ideas? Thanks in advance.

 

[The_Roadie]

Is the compressor clutch engaging? Is the receiver / dryer frosty? In other words, is there any cold air to blow?

 

[The_Roadie]

Is there any cold air available to blow?

 

[UMEXT]

Is there any cold air available to blow?

Yes, it blows cold air in the beginning. Then it stops.

 

[The_Roadie]

Sorry I wasn't clear, but I tried to be. WHEN IT QUITS WORKING, is the receiver/dryer frosty? Trying to see if the problem is in the HVAC air handling system or in the engine compartment.

It's been discussed a few times about how the AC compressor clutch can deteriorate over time and the magnet weakens and you can sometimes remove shims to restore operation when it's hot.

 

[UMEXT]

Sorry I wasn't clear, but I tried to be. WHEN IT QUITS WORKING, is the receiver/dryer frosty? Trying to see if the problem is in the HVAC air handling system or in the engine compartment.

It's been discussed a few times about how the AC compressor clutch can deteriorate over time and the magnet weakens and you can sometimes remove shims to restore operation when it's hot.

Forgive my evident stupidity, but even if I knew where the receiver/dryer is, how would I check it while driving? And if the clutch was deteriorating and weakened, how would it suddenly resurrect itself and start blowing cold air again?

 

[meerschm]

http://www.rockauto.com/getimage/ge...www.rockauto.com/info/SPI/0210066_TOP_P04.jpg

you would have to stop and raise the hood to look. google can show you what the part looks like. it is near the passenger side of the car, close to the firewall, under the hood (to the left far side looking from the front of the vehicle)

what happens sometimes is that the compressor clutch, being old and feeble, ceases to operate properly above a certain temperature. (temperature it is at, which will be higher than the outside air)

when it cools off, it can operate once again.



there are two basic parts to the air conditioning, the refrigerant system, which makes a radiator like object known as an evaporator quite cold, and a second part which moves air past this device, which provides cooler and dryer air for your comfort.

Roadie was trying to lead you to isolate which of these two parts were causing the trouble.

 

[Real McCoy]

Was there a solution to this problem? My AC started acting in a similar manner just recently.
What would I search for to find the discussion about shimming the AC clutch?

Thanks
Doug

 

[meerschm]

https://www.google.com/search?q=trailblazer+shim+ac+clutch

I actually replaced the clutch on mine.

but you can start with removing one or more of the little washers which serve as shims.

pretty simple, in a complicated way.

(if I recall the hardest part is getting to the front of the compressor. I pulled the fan clutch from the water pump, and pulled the radiator fan shroud with fan and fan clutch to get more room to work, pulled fan belt, then had plenty of access.)

you might be able to get the clutch off the pulley without pulling the fan and shroud. just need to get that hex bolt out, and the clutch comes right off. you may want to use a feeler gauge to check the gap before you start.

if you need to change the clutch, coil, and bearing, you need a good pair of snap ring pliers and good luck to do so on the truck, without opening up the r134 lines, but it can be done.

I found the clutch on E-bay from airpartsinc http://www.ebay.com/usr/airpartsinc?_trksid=p2059210.m2749.l2754



they set up a private item for your needs. clutch was around $70 a couple years ago.

 

[Real McCoy]

Thanks for the reply. I will tackle this over the weekend.
Doug

 

[goombi]

i have an issue with my driver side ..it blows warm/hot air and the rear and passenger blow cold. compressor works. any suggestions where or what to check?
thanks in advance..regina

 

[KNBlazer]

i have an issue with my driver side ..it blows warm/hot air and the rear and passenger blow cold. compressor works. any suggestions where or what to check?
thanks in advance..regina

Start a new thread, otherwise responses will be all over the place...

 

[goombi]

Thanks...I'm not very good with forums yet..