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Hi guys
I just had my AC refreshed and I have the original compressor, hoses and condenser/evaporator.
New Parts: Freeze switch (1 adjustment made to move probe a little farther away from evap for colder air...no freeze ups yet), New Drier from Roger (original one was in the car), condenser flush (a nameless someone put stop-leak in...)...btw the condenser flush can be done in place...there's a product that apparently can clean it out then you vacuum it back out. Also a new pusher fan...FF Dynamics (no affilliation except a satisfied customer) 1,500 CFM 13" that only draws 6 amps...its triggered to run when compressor comes on...in contrast to the original pusher fan circuit for AC that is pressure activated.
We also removed the compressor so several o-rings were refreshed. The air coming out of the vents is incredibly cold....really cold.
Seth I'm not sure if anything above has been done to yours but wanted to share the great result I got with the standard evap with the actions taken above...
Cold...really really cold...like your hand gets too cold.....I've been running it on recirc at fan speed 2 and 1 to hopefullly do a really good stress test to see if it freezes up....so far so good...
The AC in the Red Witch had been cold...enough. It had an r134a retrofit back in the late 90’s.
Here is what I have bought:
-reman compressor from Roger
-new drier for r134a
-new expansion valve for r134a
-all new hoses
-new AC pressure switch
-new 75C(?) radiator switch for aux cooling fan
-new r134a fittings
-all new O-rings and schrader valve cores
Here is what I have done:
-had long passenger’s side engine compartment AC line rebuilt
-flushed evaporator and added oil
I am considering buying a Spal 16” pusher fan to mount in place of the aux fan.
I am considering trying to add new silicone fluid to the viscuous fan clutch. Engine never ran hot, just think it might be a good idea.
I want another condenser because mine has a little damage. One of the upper rubber stand-off mounts for the aux fan broke, allowing the aux fan frame to rub on the condenser.
It did not wear a hole in the tube, but it is dented.
If I need another condenser, might as well try to find a more efficient one.
The Forgotten On: Very good to know that the parallel flow condenser will fit my 1986.5. Thanks!
The AC in the Red Witch had been cold...enough. It had an r134a retrofit back in the late 90’s.
Here is what I have bought:
-reman compressor from Roger
-new drier for r134a
-new expansion valve for r134a
-all new hoses
-new AC pressure switch
-new 75C(?) radiator switch for aux cooling fan
-new r134a fittings
-all new O-rings and schrader valve cores
Here is what I have done:
-had long passenger’s side engine compartment AC line rebuilt
-flushed evaporator and added oil
I am considering buying a Spal 16” pusher fan to mount in place of the aux fan.
I am considering trying to add new silicone fluid to the viscuous fan clutch. Engine never ran hot, just think it might be a good idea.
I want another condenser because mine has a little damage. One of the upper rubber stand-off mounts for the aux fan broke, allowing the aux fan frame to rub on the condenser.
It did not wear a hole in the tube, but it is dented.
If I need another condenser, might as well try to find a more efficient one.
The Forgotten On: Very good to know that the parallel flow condenser will fit my 1986.5. Thanks!
Speedtoys: Sorry to hijack your thread.
You are going to get frozen out of that car....I am just amazed at the temperature of the air coming out of the vents...one thing to note...the freeze switch...the capillary tube has a "holster" that slides over the end of it...however there isn't anything inside the evap chamber to guide that into a specific place...so it may take an adjustment or two to make sure you're pushing out the coldest air you can without freezing up....I bent mine slightly upwards (away from the evap coil) and was rewarded with a drop from 40 degrees to what must be low 30's and frankly I am a little concerned about it freezing...which is why I'm really trying to get it to freeze while I have ability to tinker with it rather than be on 1-35 coming home from Dallas and having to switch the AC off to thaw the evap! The attachment point to the evap chamber is is right up against the little holster..so just a small bend there makes a big diff....its about 4 more inches of sensor after that attachment point...
Be vigilant about the adjustment...freezing up of evap coil can damage compressors....the pusher fan in front of the condenser made a mega difference...the pullers on the engine side of the radiator just couldn't move enough air through the condenser...now I sit at a traffic light...where usually you feel the air get "less cold"...and so far it's just as ice cold as if I was going down the road.
Right now so far the only issue of concern to me is that with the AC on in stop and go traffic the temp guage goes up to almost touching the upper white line...however that is within the normal operating range. Visually yes it's a little disconcerting but normal range is normal range...another issue is it wasn't very hot here yesterday so we're going to keep an eye on it and if necessary we'll be paying another visit to FF for their Stage 4 Extreme kit for the 928...not sure what that means but ....sounds kind of extreme....
I did some google searching on the benefits of a parallel flow condenser ... some folk claim up to 30% more efficient that tube and fin style in removing heat from the compressed refrigerant - CP.
Also when people are claiming temps at the vent, doesn’t that really depend on the intake temp and how long it been running? The WSM recommends testing the temps after 10min of running at 2000 rpm
Last edited by Michael Benno; 06-22-2018 at 02:20 AM.
I am considering trying to add new silicone fluid to the viscuous fan clutch.
If you don't address the reason it left in the first place, you are wasting your time at least that was my experience. I don't know anyone that has found or fixed this problem.
I am considering trying to add new silicone fluid to the viscous fan clutch. Engine never ran hot, just think it might be a good idea.
Seth, I agree with SteveG, a leaking viscous clutch (do you _know_ you have a leak?) is like an A/C system low on freon- you can refill it, but it'll still leak out again.
Anderson has a beautiful replacement for the viscous fan clutch that is a fraction of the current left-nut price that Porsche is charging. 928 106 112 AM on the website
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I am NOT JOKING. It's not hot...maybe 72 in my garage...but still... honestly I don't know why it hasn't frozen solid...I swear I've been driving around trying to make it freeze...I know it has to be a matter of time...but this is what it's putting out with the work I've detailed above...
You are going to get frozen out of that car....I am just amazed at the temperature of the air coming out of the vents...one thing to note...the freeze switch...the capillary tube has a "holster" that slides over the end of it...however there isn't anything inside the evap chamber to guide that into a specific place...so it may take an adjustment or two to make sure you're pushing out the coldest air you can without freezing up....I bent mine slightly upwards (away from the evap coil) and was rewarded with a drop from 40 degrees to what must be low 30's and frankly I am a little concerned about it freezing...which is why I'm really trying to get it to freeze while I have ability to tinker with it rather than be on 1-35 coming home from Dallas and having to switch the AC off to thaw the evap! The attachment point to the evap chamber is is right up against the little holster..so just a small bend there makes a big diff....its about 4 more inches of sensor after that attachment point...
Be vigilant about the adjustment...freezing up of evap coil can damage compressors....the pusher fan in front of the condenser made a mega difference...the pullers on the engine side of the radiator just couldn't move enough air through the condenser...now I sit at a traffic light...where usually you feel the air get "less cold"...and so far it's just as ice cold as if I was going down the road.
Right now so far the only issue of concern to me is that with the AC on in stop and go traffic the temp guage goes up to almost touching the upper white line...however that is within the normal operating range. Visually yes it's a little disconcerting but normal range is normal range...another issue is it wasn't very hot here yesterday so we're going to keep an eye on it and if necessary we'll be paying another visit to FF for their Stage 4 Extreme kit for the 928...not sure what that means but ....sounds kind of extreme....
928NOOBIE, that is my intent. I work 12 hour shifts leading a maintenance crew in a hot-*** manufacturing facility. I want my AC to be arctic!
Thank you for the advice on repositioning the freeze switch capillary tube. I will definitely do that.
Originally Posted by SteveG
If you don't address the reason it left in the first place, you are wasting your time at least that was my experience. I don't know anyone that has found or fixed this problem.
Very good point, SteveG. I do not know that my viscous clutch has a leak. I have replaced the bearings on it, and saw no residue implying escaping silicone. The Red Witch never ran hot in the SC summer that I drove it. I just thought trying to add more silicone fluid might be a good idea based upon age.
Thanks!
Originally Posted by Rob Edwards
Piling on the thread re-direct:
Seth, I agree with SteveG, a leaking viscous clutch (do you _know_ you have a leak?) is like an A/C system low on freon- you can refill it, but it'll still leak out again.
Anderson has a beautiful replacement for the viscous fan clutch that is a fraction of the current left-nut price that Porsche is charging. 928 106 112 AM on the website
Rob, I don't actually think it has a leak. See my above comment to SteveG. However, having said all that, I will just look into the replacement from Mark Anderson and be done with it.
Thank you for that! I am almost sorta becoming somewhat numb to the pricing. I now see $100 as, 'hey, that's cheap!'
Originally Posted by DR
Seth,
I have you covered if you want a new one.
Happy Friday,
Dave
Hi Dave! Already contacting Jeannie.
Originally Posted by 928NOOBIE
Seth...
I am NOT JOKING. It's not hot...maybe 72 in my garage...but still... honestly I don't know why it hasn't frozen solid...I swear I've been driving around trying to make it freeze...I know it has to be a matter of time...but this is what it's putting out with the work I've detailed above...
Seriously....why isn't the evap a block of ice???
SWEEEEEEEEEEET!!! I want my AC to blow snow out of the vents. Good to know it is possible.
Thanks guys for all the information!
Thanks to speedtoys for bringing this up!
I am NOT JOKING. It's not hot...maybe 72 in my garage...but still... honestly I don't know why it hasn't frozen solid...I swear I've been driving around trying to make it freeze...I know it has to be a matter of time...but this is what it's putting out with the work I've detailed above...
Seriously....why isn't the evap a block of ice???
Maybe the low humidity in Kansas?
Seriously, as long as there is sufficient air flow through the evaporator, it will not freeze.
Great stuff in this thread. I will note that at 70f, any AC system should be able to blow super cold. The big question is how cold does it blow at 95F; I've seen a difference in cool down ability at 85F to 95F, is there a tipping point in there?
Also how do you know if your fan clutch is going out? Mine seems to be ok, but it's the original one and maybe I should have a spare for when/if it does go.
Car in shop having paint fixed, so I'm stuck with the 944S. That car really has the engine get to hot (top line on the temp sensor) and it has an odd vibration right at 4k RPM with the AC on. Does blow very cold (R134 refit with replaced non parallel condenser) which is nice, but it seems to dump a lot of heat into the engine to do it.
Seriously, as long as there is sufficient air flow through the evaporator, it will not freeze.
I was just about to suggest low humidity, but Kansas can be humid in summer. The good airflow through the evaporator is probably the reason it hasn't frozen....especially if all the lint was cleaned off. I noticed better airflow after I cleaned mine.
06-21-2018, 12:07 PM
