I am attempting to get my AC working which I expect to turn into a big project.
Anyway, I was replacing the blower motor and found a hose going into the back of the blower motor. The hose was packed with leaves and so was the chamber where the cage to the motor is.


What is this hose for and where does it go?


I want to blow all that debris out of their but want to know where that hose goes and if there are any other areas I need to dig to get out all the debris.

Thanks

 

You should find a matching nipple on the AC case. The hose provides a little cooling air to the blower motor.

 

Thanks!!

Does anyone have AC that really blows cold or is that a dream?

 

48 degrees

 

That is great!! Are you getting that out of the GM equipment or an aftemarket?

 

the best practice to blow all that debris out of the evaporator box is to remove the box and clean it from inside, its not that hard job (especially if you have a small block) but its time consuming. I used another approuch which is not as effective as the first, but I did got rid of most of the debris out, just remove the small resistor on the side of the box (near the ventelating nipple) and use a strong home vacuum cleaner and push its hose inside to suck everything out, dont push too hard so you dont dent
the evaporator fins.

check that out : http://forums.corvetteforum.com/show....php?t=1726044

I heard so many guys here talking about a very successful stories with their A/C, so its diffenetly worth a try. Good luck.

Hamad

 

I get 40 degrees out of my '76 vents and I live in Florida (R12, BTW). If you're not getting this temp, one of the main things to check, after being sure your system is properly working, is the weather stripping at the rear of the hood that seals against the cowling. This where hot air from the engine compartment can enter that will eventually end up coming out of your a/c vents.
I could never get my system below 45 degrees and I bought my '76 new. It got so bad the temp coming out of the vents was over 100 with the A/C OFF. I then read an article about this seal problem and so I replaced mine ($7.00). The old one looked horrible. I then went for a drive, again a/c off, and the temp was down to 75 or so. I then new I fixed the problem.
A quick way to check the seal is to coat it with grease and then shut the hood. If the grease doesn't transfer to the cowling top, you've got hot engine compartment air coming in. Replace the seal. You'll be glad you did.

 

That is on a 70 SB that I converted the POA to a cycling clutch setup from Ecklers and installed 134.I thought it was pretty decent although below 40 with R12 is not unusual as Jud mentioned.

 

43-45* here on a digital thermometer. Stock system, just rebuilt and on R12. Unfortunately I still have vent temps of 100-115* when the AC is off and I can't figure out why. If I wasn't getting that much hot air in the system, mine might would hit 40. Sometimes if I start it when the car has been sitting in the garage and turn on the ac, It will hit 42* in the driveway..But once the car gets good and hot, I get an average of 45*.

This is on my 71 SB.... I am about to start working on the ac in our 69 BB.

 

As I mentioned above, check the weather stripping on the rear of the hood. I'll bet that is your problem.

 

Yes my weather strippinig is still good on the hood but aside from that, I have my plenum door permanently shut preventing outside cowling air from coming....I mean some might still be seeping in but.... the majority is not. I have gone through EVERYTHING on this thing to prevent heating of the ac system.... nothing has made a significant different in reducing vent temps with the AC off.

 

The seal for my hood needs to be replaced. I will make sure I do that. I have never even had the AC on in this car. I am just attempting to get it working.

I started by replacing the AC hose going to the compressor. It lookes as if someone used it for leverage and creased it causing a leak. I then went to get a pressure test and it passed. I took the car to get a radio installed and the installer broke the blower motor hi/low lever on the AC console. I am waiting for that to come in.

In the mean time I replaced the blower motor and blew out all of the debris I could. I thin I got most of it and there was A LOT.

I will be charging the system and finding out how well it works or does not work before I continue to tear into it.

I am guessing that replacing the control interface for the AC and heater will be easy?? I hope.

 

If you're get 100+ temps from the vents and that is hotter than the outside temp, you must be pulling in engine compartment air. Did you try putting grease on the weather stripping to see if the entire piece is sealing against the top of the cowling? You have the same symptoms as I had and the seal was at fault.

 

Lots of good tips here. One other thing to keep in mind when you are checking the vent temp on any car is to do it at 45 mph or greater to have plenty of air across the condensor. It makes a big difference as opposed to sitting in the driveway.

 

yeah NO DOUBT I am getting engine heat in the AC system....I just can't find where. My seal seams pretty good, yet I could lay a towel over it to ensure a seal... The point is though, when the plenum door is shut, no air is supposed to be getting in from the cowl area(ie. hood leaks). I even removed the blower motor and stuck my hand up in there to make sure the plenum door shuts off all the way.

Basically the longer I drive the car, the hotter the under hood temps get, the hotter the vent temps will get....Even if its 70* outside, I will still get 100*+ through the vents. On the highway it gets about 115*.
Here is what I have done:
1) Sealed plenum door(permanent recirc)
2) Installed two ball valves on heater hoses
3) Sealed all holes in firewall and evaporator box, including the drain on the bottom
4) Installed heat barrier on evaporator box on the engine side and bottom.
5)Checked the caulking in the plenum area where the firewall and fender are glassed together..seal is good that I can tell.
6) Bought ceramic coated headers
7) Have heat shields installed on the footwells under the car

When the AC is on, its completely cool and the car seems to have no other heat sources other then the tranny tunnel, I have 3 layers of dynamat under the carpet. The heat problem is when the AC is off, that indicates that 90% of the heat is coming in through the AC system.

 

You say the seal seems pretty good. Not to beat a dead horse, but again if you haven't done so, I would put a layer of grease across the entire rear hood seal and then shut it completely. After reopening, if there are any areas on top of the cowling where the seal sits against that don't have grease, hot engine compartment air is entering your vent system. You can't just look at the seal and assume it's okay. If I were you, for less than $10, I'd replace it. You can do it in less than 1/2 hour. As I mentioned earlier, my car never ran cooler after I replaced the seal and I bought the car new in '76. If we were near each other, I replace it for you. Even if your seal is good, your hood may not be closing properly. Just trying to help and good luck. Jud

 

I will check the hood seal with grease.... BUT What about when I put the L88 hood on it with the open rear chamber? all that heat is gonna come pouring out of the engine compartment anyway. THATS why I sealed the plenum door shut because I needed to keep the heat out of the plenum area.

Thanks for your help!

 

Build an air box for the L88 hood...cowl induction and hood seal.

 

If you are going to change hoods, there is no sense in trying to seal the one currently on your car. That a look at Batmans thread above and see what you can fabricate. Good luck.

 

Aj, I had your same problem earlier, I was getting a little hot air from the a/c vents (well, it was very hot), today I made the first drive after installing back my evaporaor box, the difference was like day and night, no more hot air from the vents at all, and it was 105F when I was driving it. What I did was fixing a crack in the box and then wrapping it with zero-clearance insulation :