AC evaporator drain hose installation

[jangell]

A while back I completely replaced the AC system, including lines, compressor, condenser, heater core, etc. it’s been sitting at vacuum (and holding it quite well), and I’m filling it today. But there’s one detail I still need to do: reinstall the evaporator drain hose.

I know where the hose used to exit over the frame near the accumulator, as shown in this image (https://images.app.goo.gl/e25sQq5ougYb5v5N6). I just can’t figure out how I re-install that hose in the first place. I mean, I’m not sure how I can get my hand in there with the accumulator in the way.

I’m also wondering how bad it is to not install the hose at all. I assume it’s there for a reason.

Thanks!

— Joe

[Michael]

There is a rubber boot that sandwiches between the evap drain and the underbody and it is TIGHT! I believe the rubber pipe attaches to that boot from underneath but I am not sure how to access it other than from top and getting that boot back in place is magic. All the rubber hose drain does is redirects the water off the frame.

:Cue long winded posts about coil boots:

[eight8toy]

This brings back bad memories of working on the AC system. I think as long as you have the rubber drain port at the bottom of the HVAC box directed properly in the fiberglass hole in the passenger footwell then the water should at least drain out of the car. Maybe down the frame but at least not on the passenger's feet.

My guess is that you'd have to pull the HVAC box out to get that rubber drain hose back on.

[jangell]

The good news is that I know the drain is going through the body correctly. I know this because I forgot to remove the defrost duct and broke the bottom of the evaporator box when I forced the box free. I had to fiberglass it back together, tested that it’s water tight, and made sure the drain is going back through the body, so I SHOULD be good. I definitely don’t want to take all of that apart again.

I feel like the hose cane off when I pulled the box out of the car, but I don’t remember anymore. I definite didn’t put the hose back on before re-installing the box.

So it looks like I’m just going to let it drain onto the frame.

Thanks!

— Joe

[EdR5150]

I couldn't find a way to get the drain back on. It's also prone to clogging. That's why I made this one-piece clear drain:

59898

I was able to slide it down through the body hole, then pull it up onto the box. I then angled the drain down, away from the frame.

Blog post: http://www.16908.info/?p=3072

I had plans to make some extra drains tubes, but those plans fell through.

[Bitsyncmaster]

Nice. I did something similar.

[81dmc]

I think I used a spark plug boot though the original hole... My car's an early car though, and I had to pull out the ac box a second time to enlarge the hole in the fiberglass body.

Damn, I never want to do that again, that day sucked ass.:mecry:

[JBaker4981]

Ed,
I commend you for your instructions on your website. How hard was it to get it to feed through the spot where the original hose was?

Also, any idea how large the diameter of the original elbow is where it connects to the bottom of the Evap box? Would like to find something similar to that at Lowe's that does not have a 90 turn.


I couldn't find a way to get the drain back on. It's also prone to clogging. That's why I made this one-piece clear drain:

59898

I was able to slide it down through the body hole, then pull it up onto the box. I then angled the drain down, away from the frame.

Blog post: http://www.16908.info/?p=3072

I had plans to make some extra drains tubes, but those plans fell through.

[EdR5150]

Ed,
I commend you for your instructions on your website.

Thanks! I spend too much time on it.



How hard was it to get it to feed through the spot where the original hose was?

Not hard. The tygon material is soft, but holds it's shape well. I was able to cram it down under the evap drain, then back up onto the drain. Maybe once I accidentally shoved it down completely through the underbody. I just tried again carefully, and it worked.



Also, any idea how large the diameter of the original elbow is where it connects to the bottom of the Evap box? Would like to find something similar to that at Lowe's that does not have a 90 turn.

Looks like the internal diameter is around 3/4 inch. Not sure how large the hole in the underbody is.
60629

I had planned to make some more drains from regular vinyl tubing, but vinyl is hard to work with. The tygon tubing is expensive, so the project is on hold right now.

[JBaker4981]

Thanks for the additional info man! I've ordered a replacement drain tube last night from DMCH as a back up (for $6.28 I cant pass on having a backup) however I have already placed an order at Lowe's for similar tubing. Definitely going to give your directions a shot this week and use the DMCH as a backup in case I get frustrated or waste all of my Lowe's tubing.

I assume you fed it through the inside of the car first? The gap between the Evap Case and the center of the underbody is so small - just curious how to tackle it best on my early VIN car. Also, what is below the opening? Is it hollow or is there a cavity that leads directly to the opening in the front right wheel well?

[EdR5150]

I figured now is a good time to publish some video I shot of the drain replacement. This video was meant to me more polished and thorough, but I never found the time. Big thanks to my buddy who helped me with the video and let me manhandle two of his Deloreans. This is a rough cut, but this should answer most questions:


https://www.youtube.com/watch?v=mDlu7V61zcg


Thanks for the additional info man! I've ordered a replacement drain tube last night from DMCH as a back up (for $6.28 I cant pass on having a backup) however I have already placed an order at Lowe's for similar tubing. Definitely going to give your directions a shot this week and use the DMCH as a backup in case I get frustrated or waste all of my Lowe's tubing.

I assume you fed it through the inside of the car first? The gap between the Evap Case and the center of the underbody is so small - just curious how to tackle it best on my early VIN car. Also, what is below the opening? Is it hollow or is there a cavity that leads directly to the opening in the front right wheel well?

[JBaker4981]

You are the man! Thank you so much for uploading that!

[Bitsyncmaster]

FYI:

The drain hose or elbow on our car and all GM cars I've had has a pinch to limit the air flow loss through the drain. I've had to get rid of that pinched hose on all my GM cars and the DeLorean to keep the drain from clogging.

[EdR5150]

FYI:

The drain hose or elbow on our car and all GM cars I've had has a pinch to limit the air flow loss through the drain. I've had to get rid of that pinched hose on all my GM cars and the DeLorean to keep the drain from clogging.

Good to know. It seems airflow lost would be minimal, but you could always pinch the end of the tube, and not the elbow.

[Helirich]

I'm reserecting another old thread to ask a question. Today I had some water drip off my AC evaporator housing on the pax carpit. I was looking for the drain tube and mistakenly found the "cooling tube" for the motor. I pulled it off the motor and sprayed some compress air in it. When I looked under the car, some water had come out of the real drain tube.

At first, I thought maybe I unclogged it, but it didn't seem right that the drain would be off the motor. After a lot of searching, I think what really happened was I pressurized the whole evaporator box and blew some air out the real drain hose.

I later found the real elbow/hose and, of course, it looks tough to remove as everybody says. The fact that I was able to blow some air through it makes me think it's not completely clogged. But I'm sure it has some mold/algae in it. I could blow air backwards through the tube from the out side, but that seems like I would just be delaying the clog.

So finally my question. Is there a place that I could introduce a bleach/water into the box? I figure it would wash the rest of crud out.

[81dmc]

So finally my question. Is there a place that I could introduce a bleach/water into the box? I figure it would wash the rest of crud out.

If you pull the blower motor, you can see the evaporator in the box.

Use a turkey baster to suck up bleach water solution and inject it towards the evap.

[Helirich]

If you pull the blower motor, you can see the evaporator in the box.

Use a turkey baster to suck up bleach water solution and inject it towards the evap.

That sounds like a plan. Tomorrow I will try it. Thanks!