A/C Smuggler Box Evaporator Water Drain

[RNajarian]

Hi Gang (bear with me, I want to be as detailed as possible)

In the process of preventing my 1975S dealer installed a/c from freezing up I discovered/uncovered another problem.

After a drive in which the evaporator froze up, I parked my car to inspect, verify the evaporator drain was clear. On humid days the car would drip very cold water after/during a/c use, likely from the evaporator, yesterday was no different.

HOWEVER, upon inspection I noticed the cold water was not coming from the evaporator drain tube but from what seemed to be a factory plug on the bottom of the smugglers box three inches in diameter. Photo below shows the removed 3 inch plug next to what is assumed to be the drain for the smugglers box.



The photo below shows the removed broken plug next to a part of the evaporator drain which broke off



After removing the 3 inch plug I reached in to the hole and removed decades of crud and mud. Interesting to note there was also cold water dripping from the 3 inch hole.

The evaporator drain was moist but not dripping water.



I used a soft wire (stiff enough to unclog but not stiff enough to puncture the evaporator) what I got was the same crud/junk as was in the 3 inch hole. In the process of removing the wire the lower inch of the rubber evaporator drain broke off. Close inspection revealed it was pretty well occluded with crud/mud. You can see that fragment on the left in the first photo.

Below are close ups of the two exposed holes





I am assuming the textured plastic box in he last two photos are the evaporator box.

What do you guys think?

1) Do I have to remove the evaporator to re establish proper drainage?
2) If I leave it as is and allow it to drip to bottom of smuggler box then drip through hole am I inviting the Rust Monster?
3) Is it safe to re-seal the 3 inch hole

The only time this car sees rain is through the window of the Garage, so will this A/C moisture be inviting disaster? For reference I have added a photo from KC911 showing the other side of this equation.




Thanks for your thoughts

[wwest]

I hope not...

Post #589

My AC burns me up --- Help!

Air in your system.

Aftermarket Serpentine evaporator.

[Ronnie's.930]

In order for water to come out of that chassis plug, it would either have to overflow the evaporator box and run out of the seam where the top of the box meets the bottom (which is above the evaporator core), or the evaporator box is cracked or has a hole in it. Regardless, I would say that you have found a contributing factor for your evaporator freezing problem.

At a minimum, you should remove the evaporator intake duct and look in there with a flashlight and mirror to see if there is any visible mold & filth buildup (like in the pic of Karl's evaporator that wwest posted above) that can be removed without too much trouble.

Removing the evaporator box top is a real pain in the ass if the evaporator box is left in place, but to remove the box requires discharging the system (you probably already know this).

If it were mine, I would remove the box for a thorough cleaning of it and the evaporator core, etc., and clean/repair the rust from the inside of the smuggler's box at the same time.

[wwest]

Ron, with condensate drain plugged it will probably run out the opening around the plastic sleeve on/in which the resistor pak is mounted.

[wwest]

OEM/factory evaporator, likely yours..

[Ronnie's.930]

^^^ Right, that slipped my mind - duct entering he evap box is by no means air or water tight.

[wwest]

Again..WOW!


I'm finding it more and more amazing that you are getting such great A/C performance out of a 1975 (basically) factory A/C system. R12, non-barrier hoses, etc.

I suspect, like Karl, you'll end up pulling the evaporator to clean it.

In the meantime the system will be more useful if you find the proper Max cooling "calibration" (non-freeze-up) point for the thermostatic switch using the procedure CG suggested. Once you find the non-freeze point on the switch you should not ever set it above that point, as once the ice forms it will generally remain in place until the system is turned off.

On the other hand replacing the 40 YO switch as a preventative measure might be a good move.

The switch is one of the more common failure points for the system.

Loose the capillary gas somehow or have the switch contacts "weld" together will result in other system failures.

For instance, in your case, the max setting of the switch along with the icing of the evaporator is likely resulting in the compressor running continuously, driving the high side pressure to extreme levels. Making it surprising that your R12 refrigerant loss is only about 3 Oz/Year.

[wwest]

URGENT..!

Thinking it through..

You need to check the functionally of your thermostatic switch.. NOW!

Condensate deep enough to overflow the inlet sleeve is probably the result of a switch failure.

[GH85Carrera]

It is fairly simple to pull the foot-board in the passenger side and then the resistor pack and take a look at the bottom of the evaporator. The picture on post 5 was my evaporator. Zero doubt that was part of my issues for not great AC. I just replaced it with a new evaporator from Charlie Griffith.

If your evaporator looks as bad as I suspect it does it is worth the effort to recover the R-134a and replace the evaporator. My drain hose was not in the proper position and it is a real challenge to get it back to the proper orientation with everything in place. It is easy once it is apart.

If you have the R-134a recovered the rest is fairly easy to do. Pull the entire evaporator and box out and open it up and clean it out if it looks dirty from the passenger side air intake. Not one bit of the AC work is difficult at all except the refrigerant recovery and recharge.

Be VERY careful with the white thermostat "wire" that goes into the evaporator. Do NOT bend it any more than necessary to get it out. Take lots of pictures as a reference. Slide that "wire" out and make good notes on where the brass tube is and put it right back in a similar location in the new evaporator.

If your Receiver dryer was not recently replaced, replace that when the system is discharged as well.

[wwest]

Oops.....

Originally Posted by RNajarian

My apologies for the error. Kuehl knows A/C!

I stand corrected. My SC was updated from R12 to R134a.

The compressor must have been swaped out in the conversion

Maybe better explanation of the ~3 Oz/year leak rate.

[RNajarian]

Originally Posted by wwest

URGENT..!

Thinking it through..

You need to check the functionally of your thermostatic switch.. NOW!

Condensate deep enough to overflow the inlet sleeve is probably the result of a switch failure.

Everything that has been posted to date is valid and certainly worth consideration. I do feel that it is important to consider the design of the evaporator box. The design has changed throughout the years

Below is a evaporator box circa 1974. Note the holes on the bottom of the box, presumably for condensate



I spent more time under the car this morning and removed an seal where the evaporator drain was.



Another (clear/better) photo of the evaporator drain area does not show a connection of the broken rubber drain to the bottom of the evaporator box.



So without removing the evaporator box, I can assume the design of my evaporator is similar to the one above with 6 small holes on the bottom.

In fact do I see a small hole in the right portion on the last photo?

I'll try and get a better/closer photo and verify if in fact I do have the evaporator box with six small holes.

[RNajarian]

OK Here's a couple more photos

This one appears to show two small drain holes



I verified these are drain holes by (gently) placing a small diameter screwdriver in one of the holes



The history I got from the daughter of the previous owner was that the car sat outside under a tree "and the weeds grew around it." When I was cleaning out the crud from the 3 inch hole I actually got some Vegetive material, small dried grass like sticks.

SO,

I am assuming the original design of this 1975 S dealer install was an evaporator box with six small drain holes with a piece of hose connected to a rubber seal to drain the pooling water from the bottom of the smugglers box



When the evaporator hose clogged up the water pooled at the bottom of the smugglers box and found its way to the three inch hole to the driver's side of the smugglers box.

I may CAREFULLY add an additional drain hole to the bottom of the evaporator box to enhance draining.

[kuehl]

If this is your evap box, although dealer installed it is not a more common Behr evaporator box or evaporator (designed for the 911 system smuggler's box well.).

If the small plastic protrusion on the right is the condensation drain outlet, it pointed downward when in the smuggler's box well, you need a drain tube leading from it and exiting the bottom of the smuggler's box well.

[wwest]

Hmmm..


Does anyone know?

Does the evaporator drain tube (partially) hold the plastic case in position?


With plastic drain tube (possibly) sheared off migh the case shift position?

In any care before you drill it might worthwhile to have someone shift the plastic case from above to see if the drain tube opening can be moved back into position over the chassis hole.

[RNajarian]

Originally Posted by kuehl

If this is your evap box, although dealer installed it is not a more common Behr evaporator box or evaporator (designed for the 911 system smuggler's box well.).

If the small plastic protrusion on the right is the condensation drain outlet, it pointed downward when in the smuggler's box well, you need a drain tube leading from it and exiting the bottom of the smuggler's box well.

Yes I agree, though I think that protruding object is not a drain. Probably a support for the bottom of the evaporator box to keep the box elevated from the floor of smugglers box. Of course, I am only a weekend warrior and could be WAY OFF BASE HERE, but I think the evaporator box we are talking about (six small holes) drains condensate via those small holes.

The six hole evaporator box is different than this presumably later unit with a obvious large gauge drain hole



At the end of the day that $&@! Box has to come out

[wwest]

Or if, as CG says, your's is not the "factory box/case maybe the box/case drain tube NEVER matched up with the chassis hole. As long as the chassis hole wasn't plugged it likely wouldn't matter.

[RNajarian]

Originally Posted by wwest

In any care before you drill it might worthwhile to have someone shift the plastic case from above to see if the drain tube opening can be moved back into position over the chassis hole.

I do not think there is a large gauge drain hole, the evaporator box is pretty snug in the smugglers box, I do not think it has shifted a drain hole out of sight.

There are no other egress holes in this area for condensate. I am pretty sure I have the box with six small holes as a condensate drain.

[wwest]

And the answer is...

If the refrigerant hoses/connectors enter the evaporator openings from the driver's side that first case you pictured probably is NOT your box/case.

You previously said that the R/D was in the passenger side wheelwell....

Which leads me to believe that you probably have the one you first pictured.

[RNajarian]

Originally Posted by wwest

And the answer is...

If the refrigerant hoses/connectors enter the evaporator openings from the driver's side that first case you pictured probably is NOT your box/case.

You previously said that the R/D was in the passenger side wheelwell....

Which leads me to believe that you probably have the one you first pictured.

Well . . . Yes and no. Here is a photo of the top of my evaporator box. Similar to the one we have been talking about. But obviously different when compared to the top of the unit we are talking about.


This is the top of the six hole unit we have been talking about.



My blower/squirrel cage is vertical, as seen to the right of the first photo in this post, and verified by an inspection camera fed through the passenger vent.

I suspect I have a similar design to this six hole box. Refrigerant enters and exits from passenger wheel well. Receiver dryer is on passenger side also.

[wwest]

Similar design.... Not even close. Maybe CG has seen one of those?