A little while back, I posted up a problem I was having with my AC.

What was happening was when I switched the truck and AC off, a very loud hissing was heard near the front passenger glove box/wheel well.

A number of helpful suggestions as to what the noise was, caused me to do a little more research into how an AC works.

A few guys said the sound was normal. A couple said that it was the high and low sides of the AC, equalising out pressures.

I just had a ****ling feeling, that all wasn't well and that this very loud hissing, wasn't normal.
Also, the metal inlet pipe to the AC condenser was so hot, I couldn't touch it. I remembered that this wasn't like that in the past and It should not be as hot as it was.

Please bear in mind I live in the UK and don't use the AC much if at all, except for the weekly switching on/off for 10 mins or so, just to let the system get the refrigerant circulating etc.

After much head scratching, I found that the AC condenser fan was intermittent.
Also, when I tried to stop the fan spinning, there was hardly any power/torque behind the motor.
When the motor was stopped, a sharp tap with a screwdriver, caused the fan to slowly spin up again.


Anyhow using some suggestions from another fellow Dodge truck owner,I finally managed to pull away the AC condensor shroud and then, after many cuts and bruised knuckles, I managed to get the fan motor free.
The reasons why I didn't uncouple the refrigerant lines and remove the whole AC condenser unit making it easier as per the workshop manual are, that I live in the UK and all this kinda' stuff would be sooooo expensive, like megga bucks for re gassing the system etc. $1000's of Dollars but in my case, £ pounds LOL

I sourced a new fan, but because my 03 has had a fan/shroud/motor and electrical pigtail upgrade, I would have to purchase all of this new stuff, as a new fan motor wouldn't fit my old shroud. All that would cost $572.
I believe a fan in the USA would be around $100 ????

So, money being short, I had to rebuild the original fan motor.
Back to re reading about brushed DC motor theory from my old Electrical background books.

No companies in the area would do the job for me so I resorted to the good old DIY approach.

I split open the motor and found that the brushes and the commutator had seen much better days. In fact, the copper pigtail attached to one of the brushes, crumpled away on dismantling. Things were that bad.
Anyhow, I managed to source a brush set, which in itself was no mean feat to match the originals.
I cleaned up the commutator. Put a "matched to the commutator" profile onto the brush set, using very fine glass paper and generally cleaned up the entire motor.
A quick, temporary re-assembly and test, proved all was well. The motor span up immediately and had bags of torque and indeed, I couldn't stop the fan from turning by hand.
After several more hours on the spanners re installing everything, all was back in the Hemi and I took him out for a road test.
The fan pulls masses of air through the AC condenser now, keeping the temperature of the refrigerant down to normal levels. When I switch off, there is no loud hissing noises, only a very quiet hissing like I remember it used to be and the AC is plenty cold.
The input line to the AC condenser was now cool to the touch and not so hot, I couldn't touch it.
I believe the very large temp difference between the low and high sides of the AC, due to the AC cooling fan not running, caused an unusually large pressure differential between them, and when the AC was switched off, this was what I was hearing as the pressures readjusted themselves resulting in this loud hissing.
I was lucky, in that I spotted this situation early enough and stopped using the AC and the system didn't vent the pressure off, resulting in a low coolant problem.
Any way, a long post but I hope it might be useful to somebody out there at some point.
Al.[/align]

 

Hi Al Thanks for informative message on AC.
Maybe you can help me out. No one has been able to assist me in this. 97 dodge caravan and live in Hawaii so use the air a lot. I have condensation leaking from heater core box by gas pedal. It is clear water not anti freeze. I removed drain hose and there was no obstruction. And absolutely no moisture at hole. All water is being diverted into eater core box. I opened the box a little and made a aluminum shoot to run the water into a pan between the front seats. AC/Heater work fine.
I also removed the wiper pan and ran water into the pan and it ran out of the drain. But nothing from AC drains.
No one so far can help me find a solution to this problem. I certainly do not want to remove the dash and steering column to find it is something I could have done otherwise.

Do you have any ideas or suggestions? Do you have any diagrams of the ac internal vent system? That would at least give me an idea as to where the blockage is.
Many Thanks conramana

 

conramana---

Have you removed the short (I'm assuming) drain hose that comes out the firewall and actually looked inside the drain pipe with a mirror and flashlight??

Quite often these can get plugged/blocked with mold, leaves, bugs,-----spider webs(like your gas grill).

These are an atmospheric drain, so they are easily plugged.
Try that first, before you even begin looking at the HVAC housing and such.

I'm not sure, and I don't have a service manual on your vehicle, but you may also be able to access the area, some, through the cowl inlet at the bottom of the windshield on the outside of the van---where your outside air comes in.

 

Al,

Good to hear you got a good line on your A/C troubles.

I predict that some time in the near future you will be abandoning your current profession and opening a Hemi repair shop that specializes in propane injection and performance mods. You will by default know these things inside and out!!!