Hi guys, I tried to sneek this question in on another post about debris clogging the flow with no answer. The part of our A/C systems that is in the cab that the air blows through to cool the car,(I think we call it the evaporator) can it get clogged with debris the way that a
radiator can? I have cold air and it is o.k., but the flow is weak. Is there a way for the "fins" to be covered with crap after only 23 years?
How tough is it to access the evaporator to check it? dd
1988 coupe stock base model automatic. blood red with saddle leather.

 

Send a PM to Suncr. He'll give you really good A/C advice.

 

yes it can get clogged with Debris

Check this out:
http://vettextc.net/jeff/Evaporator/Clean_A-C_Evap.pdf

 

Wow ! That make me anxious about what is hiding inside mine...

Nice write-up, Jeff

 

And when they look like that, it's because they're leaking. Have a shop stick an Electronic Leak Detector in the vents to verify and then replace it.

 

daddog..... I think I can help. Theoretically, anything in an AC system can get clogged. But, before you do anything, look at everything in the AC system first. You have a compressor, evaporator, condensor, drier, orfice tube, and a bunch of piping.....that's it. From my experiences in the automotive AC business, if your GM car is not blowing cold, but the compressor is engaged and running, two things are culprits; your low on freon OR you have an obstruction. First things first, make sure your high side pressure and low side pressure's are where their supose to be. BTW, you can pick a cheap set of AC gages up for under $40..... Here are a few things to look for with a set of gages...

If your highside presure's higher than it should be (for example, 84-89 corvette 230-250 psi high side and 40-55 on the low, JUST EXAMPLES, remember!) ... and the low pressure side is lower than it should be, you have an obstruction in the system. The MOST LIKELY area for an obstruction is (#1) the orfice tube. The other is the condensor, in front of the radiator. If your AC appears to be working normal and not blowing as cold as it used to, check the pressures. Let me know the year you have and I'll look up your pressures tonight to tell you what they should be at.

Keep in mind, with AC systems, there are many variables to cause your system to "get goofy"..... that's the most likely one I can tell you. I'll check back tonight.....

 

thanks for the easy to understand information kuhndog, my car is 1988.

 

Jeff. I just printed your easy to read and understand write up on the a/c evaporator.
Thanks for the help! Mine is 1988 probably the same? dd

 

Oops daddog, it never crossed my mind that you were talking about cleaning you evap coils. I thought you were talking about a clog internal to the AC system. If it helps, you can buy coil cleaner to clean your evap too. You drill a 1/8" hole into your evap box, insert the spray can nozzle into the hole, and empty the can. It'll break down the grims on the coils.... I've seen other tech's use it on hard to reach evaps. Just my 2 cents! Good luck!

 

Don't even think about it - the Factory coil has a foam filter on the inlet side and if compressor oil hasn't allready turned it into a big gooey mess, the coil cleaner will. However, if you want to try it anyway, there's no need to drill any holes as there's a nice big one if you simply remove the Blower Resistor Pod (Manual Air) or Blower Module (Electronic).