[fleming23]

I just spent the past few hours looking at various topics regarding the A/C evaporator core and how over time leaves, debris & other crap can find it's way into the evaporator core and cause performance issues. I replaced my A/C blower motor 2 weeks ago and need to take it back out and put in a new hamster wheel (mine had a small crack that I didn't think would matter but it makes a horrible squeal when on the highest setting.) While I have the inner fender out again I wanted to try to clean the evaporator core just to make sure things are working as best as they can. I know the outer evap case has a few bolts holding it to the firewall. My question is, can you remove the bolts from the case and just slide it forward enough to access everything? I absolutely don't want to evacuate the system. I thought about taking the blower motor off and feeding my compressor air hose into the opening while using the shop vac to suck up any thing that gets blown around. I don't know how effective this will be as I didn't really look into the opening when I replaced the motor last time. If this method will work I would much rather try to just blow air around and suck the crap out then take the entire thing apart and try to reseal everything. Every post I found on the site just mentioned replacing/retrofitting or completely removing the a/c but no one seemed to document or mention just cleaning an otherwise working system.

Thanks guys!

 

[67 vette guy]

If you do not want to reseal the unit, I would not take it off the firewall. There is a large seal that could tear very easily. Some even have that black chalking around the seams. I have removed several evap cases off firewalls and was surprised by what was stuck up against the evap core. Make sure the nipple fitting on the bottom of the case is intact and not missing.

 

[SSuper Dave]

You might want to remove the nipple on the bottom during the cleaning, it will leave a bigger hole for trash to come out of and ensure that the nipple does not get plugged up.

 

[fleming23]

If you do not want to reseal the unit, I would not take it off the firewall. There is a large seal that could tear very easily. Some even have that black chalking around the seams. I have removed several evap cases off firewalls and was surprised by what was stuck up against the evap core. Make sure the nipple fitting on the bottom of the case is intact and not missing.

You might want to remove the nipple on the bottom during the cleaning, it will leave a bigger hole for trash to come out of and ensure that the nipple does not get plugged up.

I know the black rubber nipple is still there because I knocked it off accidentally and made a mental note about how deteriorated it seemed. So, for those of you who have worked on one of these do you think my plan of using compressed air and a shop vac will do any good? I don't really know what is going on inside the box. I guess it can't hurt but I would like to only have to take this apart one more time.

 

[LeoP]

Try this, take the resistor out of the housing and with a small tube, vacuum out the housing as well as you can, be careful around the evap while in there. Good luck, let us know how it turns out.

 

[lsrx101]

In my experience, air won't do the job real well. It will make a difference, but it won't get the crud that's been sucked into the inner fins. The only thing that will get that out is soapy water, lots of it.
For that, you really need the evaporator exposed, if not removed completely. You need to be able to flush it out in the reverse direction that the crud got sucked in.

If you absolutely don't want to open the evaporator case, Coil cleaner, then water sprayed through the blower and resistor openings works better than air alone. Let it drain via the evaporator drain and suck out any loose debris with your shop vac. If it happens to dribble inside on the carpet, it's only soapy water after all.
For a good strong spray, I use a gear lube bottle cap attached to my garden hose.

 

[fleming23]

In my experience, air won't do the job real well. It will make a difference, but it won't get the crud that's been sucked into the inner fins. The only thing that will get that out is soapy water, lots of it.
For that, you really need the evaporator exposed, if not removed completely. You need to be able to flush it out in the reverse direction that the crud got sucked in.

If you absolutely don't want to open the evaporator case, Coil cleaner, then water sprayed through the blower and resistor openings works better than air alone. Let it drain via the evaporator drain and suck out any loose debris with your shop vac. If it happens to dribble inside on the carpet, it's only soapy water after all.
For a good strong spray, I use a gear lube bottle cap attached to my garden hose.

That is exactly the kind of information I am looking for. I don't even know if I have any issues with debris clogging my evaporator core but while I have everything apart one more time I thought I should at least try to get everything cleaned out as it will never be easier than right now (pending complete removal of course.)

 

[JJ'65]

Take a look here: "flushing forum"...

http://www.autoacforum.com/categories.cfm?catid=23

 

[fleming23]

Take a look here: "flushing forum"...

http://www.autoacforum.com/categories.cfm?catid=23

I searched various posts in this forum for probably 1 1/2 -2 hours and googled random topics and not once did I come across that. Thanks for the reference! If nothing else it'll give me some reading to do and hopefully learn a little more about the inner workings.

 

[lsrx101]

I searched various posts in this forum for probably 1 1/2 -2 hours and googled random topics and not once did I come across that. Thanks for the reference! If nothing else it'll give me some reading to do and hopefully learn a little more about the inner workings.

The ACKits forum (sponsored by Arizona Mobile Air) is by far the best mobile AC specific forum on the 'net, IMHO.:yes:
I sometimes add a suggestion to visit that forum in posts that I respond to here.
It is geared toward DIYers and frequented by quite a few MVAC professionals who offer advice and suggestions to folks who may be attempting AC repair for the first time.

There's also a ton of info in the Tips and FAQ section on the GM POA/TXV system from 72 and earlier. The search function is your friend.

ACKits is one of my preferred suppliers for parts, especially for older systems. Tim won't sell anything on the ACKits site that he wouldn't use in his own shop (AMA). They also have access to many parts not listed on the website. One email/phone call and they can usually have it to you quickly.