[DML] Re: Poor airflow thru heater-A/C

["Dave Swingle" <swingle@xxxxxxxxxxx>]

Any of this is possible - to find out you'll have to go look at the 
car. There is no way to tell which of the things it could be based on 
only a written description. Here are some thoughts on what to look 
for:
---
If the drain hose is plugged you get wet carpet. It does not impact 
the air flow. The end of the drain hose is visible if you remove the 
access panel under the spare tire. When the A/C blower is operating 
you should feel some airflow from the hose. You should be able to 
blow thru it.  

---
Air flow can be slowed by many things - you could have an inoperative 
vacuum-controlled door, a reversed/bad motor, an evaporator full of 
leaves. The only way to tell will be to go thru some troubleshooting 
and eliminate things. If you remove the motor you can get your hand 
in the evap case and see how much gook is in the bottom. Clean it out 
as best you can, anything in there holds moisture and will cause the 
evaporator to corrode just that much faster. 
---
Trace the vacuum hose routing to make sure that everything is in the 
right place. There is a great diagram in the tech manual (not the 
service manual). Use a mighty-vac (hand vacuum pump) to manually 
operate the vacuum doors in turn. 
---

A quick check on the fan is to remove the fan from the mount but 
leave it connected. Turn it on while holding it in your hand. Facing 
the blower it should turn counterclockwise. 

You can easily reverse the fan to see if this is the problem. The fan 
is under the dash on the right side. There is one red wire and 
several black wires that terminate there. To reverse the motor you 
only have to swap the wires. There is only one lug where the red wire 
oes, so to hook up the three black wires there you'll have to make up 
a jumper from spade connectors. Then you can connect the one red wire 
to the original ground, and the three black wires to the 
original "hot" lead. This will reverse the motor, if your airflow is 
suddenly a lot better then someone used the wrong fan at some point 
(there's a fan on most of the cross-ref lists that does this!). 
If you decide to leave it this way keep in mind that the case of the 
fan motor is now "electrically hot". 
---
Another thing to consider - why did the original fan motor fail? 
Heater fans normally last a pretty long time, normally the life of 
the car. BUT - if the drain is clogged and the evap case fills up 
with water, in addition to eventually soaking the carpet on the right 
side it will splash over into the fan motor which makes it get rusty 
and lock up. 

----

AC not being cold enough is a refrigeration problem. Get the airflow 
right first, if it's still not cold you're going to need to find 
someone who can check and/or recharge the system. 

Dave Swingle


--- In dmcnews@xxxxxxxxxxxxxxx, "sweetp01569" <paul.sweet@xxxx> wrote:
> Perhaps I have the same issue.  With my blower on the highest 
> setting (with AC on or not), it seems like mediocre flow through 
the 
> dash and door vents, but hardly any air throught the floor.  I 
> didn't even know there were floor vents until I read these posts!  
> Also, AC is not that cold,either.
> 
> Could I have clogged evap and drain hose, or could my blower also 
be 
> reversed?
> 
> Also, where is the end of the drain to attach a vac?  
> 
> Thanks,
> 
> Paul
> 
> --- In dmcnews@xxxxxxxxxxxxxxx, Jake Kamphoefner <jakekamp@xxxx> 
> wrote:
> >  
> > Dave,
> >  
> > I was recently in the same situation.  Here's a couple things I 
> checked to fix my problem:
> >  
> > - Make sure the blower and squirrel cage are correct.  There are 
a 
> lot of GM equivalents that fit perfectly, but the blower motor 
> either turns the wrong direction, or the squirrel cage is cut to 
the 
> mirror of the DeLorean (that is, it is made so that turning the 
> opposite direction causes the air to flow the same direction).  
> After I replaced my blower with an OEM that I bought amongst a hand-
> full of other parts, my air flow highly increased.
> >  
> > - I also resealed the infamous foam on the back of the A/C box
> >  
> > - Cleaning the evap?  Here's how I did it.  I taped a wet shop 
vac 
> on to the drain hose.  Then I removed the blower motor and the 
> resistor to give extra room to get my hands in, and pulled back my 
> carpet to lay down some old towels.  Start by dumping a little 
water 
> into the evaporator box, then use your contortionist skills to 
reach 
> into the box and pull that gunk out.  Keep pouring water through it 
> and make sure it's making it to the vac.  You may have to stop to 
> unclog the line a couple times.  Then I put a length of clear hose 
> on the end of my garden hose, and fed it into the box.  With the 
> hose on *slow* (it's a lot more water when coming out of the small 
> clear hose), I nozzled the tube with my thumb and sprayed the 
> evaporator for a long time.  Be careful not to get more water in 
> than the drain hose can handle.
> >  
> > Oh yeah, and this job sucks.  But it's better than removing the 
> evap.
> >  
> > Jake







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