HVAC woes, 1981 Jetta "special edition" 2-door wit

[dangerous_D]

Hi new friends,

I recently acquired a 1981 Jetta "Special Edition" coupe.  It is a German-made 1.6 diesel 2-door with A/C.  The guy I bought it from bought it from his neighbor after he had seen it sitting in his neighbor's driveway for "a few years."  He bought it and did a lot of work on it, but he didn't fix everything before deciding to sell it.  

The car runs quite well, but the entire climate control system is not functional.  I've spent countless hours searching this forum and the Vortex and I've learned quite a lot.  I have a Bentley and I have the dash halfway out.  I replaced the A/C relay and I have a new heater core and receiver/dryer ready to swap in when I get the dash out, as well as an A/C conversion kit.

I have 2 questions.

First I want to get the heater blower working.  It does not work on any speed setting.  I will test the switch when I get it out.  Every time I turn the blower switch to anything other than level 0 the oil pressure light on the cluster illuminates.  Has anyone seen this symptom before???

Second, I have no idea where to begin working on the HVAC system.  I just realized that the HVAC system MAY be working, but I can't be sure since the blower motor is inop.  The Bentley is weak in this area, to say the least.  I'm curious what are the chances that the HVAC system will be working after being parked for ~5 years?  Is it good practice to replace the lines and valves?  Can someone point me to a diagnostic troubleshooting procedure for the HVAC system?

I greatly appreciate any guidance!!!

[jtanguay]

if the HVAC system works, you're pretty lucky.  what usually happens is that if the a/c is not used, it will fail.  which is why i think automotive manufacturers set a/c on with defrost, and also to dehumidify the air...

me personally i would (and have) switched to duracool or similar hydrocarbon refrigerants.  their product comes with a/c oil in the can so you don't need to add more.  its also not as toxic as r134a and has a single larger molecule so it doesn't leak past o-rings as easily, and apparently gets a few degrees cooler too!

for the blower its probably the switch, or a fuse, unless the blower motor is shot.  are you replacing the heater core out of necessity or just regular 'maintenance'???  mine blew so i was forced to change it, and upon inspection the foam doors were so bad that i had to completely rebuilt my heater box  :x and its a fairly huge job!  but on a mk2 you don't need to remove the whole dash, but i think you do on a mk1/mk3.   its a good learning experience  :lol:

[dangerous_D]

Great, thanks for your input!  I'm replacing the heater core to be thorough in my cooling system job.  The cooling system was neglected in the past so I want to make sure I get 'er done right this time.

As far as the HVAC system goes, should I replace all the vac lines and valves or are they probably ok?  Is there a proper procedure to test the lines and valves?  What about the AC compressor and clutch, are they suspect, too?

Thanks again!

[dangerous_D]

Turns out this one was the blower fan switch AND a problem with the wiring.  When the PO replaced the fuse box he put the X terminal of the fan on G9 instead of G7.  That explains why the oil pressure light came on with the fan switch.  The old blower motor was extremely oxidized, but I was able to get it moving with some WD-40.  I'm replacing it with a new fan for good measure.

I'm nearly ready to put the dash and HVAC box back in.  One thing I'm curious about is those vacuum damper actuators.  Is there a relatively cheap replacement part for these?  ECS Tuning has the double vacuum actuator for something like $125 but they don't have the single actuators.  The rubber diaphragm looking thing is cracking and I have no idea if they will work.

PN for the double vacuum unit: 171 820 677
PN for the single vacuum unit: 171 820 627   (edit: corrected part number)

[jtanguay]

i'm pretty sure they're dealer only

you might want to try some armor all on the rubber to try and extend the life, but it might not do much.  i had a broken gear from a door being jammed (the big front door).  i need to glue that thing back together.

[dangerous_D]

Hey, thanks for your input!  I'll just say I hope the original actuators still work...




Anyone ever rebalanced a blower motor impeller?  Mine is way out of round and scrapes the housing on speeds 3 and 4.

[RabbitJockey]

is that on the old motor or the new one?

[dangerous_D]

The new one.  It's not cylindrical.  There are a few little metal balancing weights on the impeller but I haven't touched them.  I have tried to "mold" the plastic back to round with my hands and it has helped.  I just hope it will maintain it's shape.  When I left it yesterday (Monday) there was no contact between the impeller and the housing.  I'll check again Friday.  Theoretically any change in shape necessitates a rebalance. 

I know, I know, it sounds stupid.  I've got the dashboard out right now and I don't want to EVER take it out again so I want to make sure I do it right and permanently.  If I get everything back together and the blower fan starts buzzing a week later I will become frustrated and I will probably become angry.  If I become angry I may break something, which will only increase the length of my Jetta todo list. 

[dangerous_D]

ECS Tuning carries the double vacuum actuator for $105: http://www.ecstuning.com/Search/171820677/

1stvwparts also carries it, they charge $85.  Go to www.1stvwparts.com and search for 171820677

[dangerous_D]

Finally, I found the single vacuum actuator.  The part number on the actuators from my car must be no longer available.  The equivalent part number is 323820627 and both ECS and 1stvwparts stock it, though 1stvw parts is significantly cheaper.  VWPartsDepartment.com also has it, but they're in San Jose and I'd like to avoid the ridiculous CA sales tax. 

If you're sick of gluing your old-ass vent outlet assemblies back together every time you bump into them those assemblies are available new from the three retailers above.