A/C Question - 1986 Carrera

[Newell33]

Hi Guys

I have a question concerning the A/C on my 1986 Carrera. I haven't had a lot of time to diagnose, so I'm really just looking to help narrow down my problem. The A/C currently does not blow any cold air. It has been converted to R134A at some point in its life. When I first got the car I turned on the A/C on the console only to find that the compressor was not kicking in. I decided to purchase one of the "all in one" A/C cans with the guage and proceeded to top off the system. When I hooked up the can I noticed that the system was just on the "needs filled" threshold. After topping off the freon the compressor now kicks on, but I don't have any cold air.

After a little review of the system, I did find that the blower for the front condenser is not working. I have power to the blower when the A/C is on, but the blower motor doesn't spin. I know that this will certainly affect the temperature, but one thing I noticed is that the vent temperature doesn't seem to change whether I'm driving down the highway, or sitting at a stop sign in town. If the rest of the system is operating properly, wouldn't I at least feel some cold or cool air driving down the highway with the air passing over the rear condenser? I realize that I should probably get the system checked with a set of guages, but I wanted to at least determine how much of an affect the front blower has on the system.

Thanks in advance for any insight!

On a side note... If anyone has a good used front blower for sale, please PM me!

Josh

[Josh D]

Your best bet it to have a vacuum pulled on the system and do a rate of rise test to see if you have any gross leaks. If you added refrigerent to a leaky system, or one that has air in it, your just wasting time and money.

Also, I'm not sure how it would be possible to use one of those 'recharge in a can' on our cars. The only way to get the correct pressures are to have the car running, at 2K rpm, and the lid down to get airflow through the condenser. Easy to do with a set of guages with hoses. I've seen those recharge in a can, and the hose is 15-20" at best. How were you able to use with lid down?

If it's been dead for any length of time, you can be certain that it will need at least a new receiver/dryer. As far as the front blower motor, they do fail. I had to replace mine as well. Our host sells them. You should still get cool air even if this blower has failed if everything else is working and ambient temps aren't extreme, but the blower definetely helps, especially when the car isn't moving.

[kuehl]

Josh,

There will be several components of the system you will need to look at, and along the way determine if the system is stock or has had upgrades.

Here are some basics on the ac and your system:
1) Topping off a system seldom works 'ideally', better to evacuate, charge and test.
2) The day the 911 rolled off the factory floor, because of 40 feet of hose, they leak refrigerant. The higher the pressures, the more it is used, the older the car, the more it will leak.
3) If you want to DIY (do it yourself) I'd suggest take the time to research the threads on AC here in Pelican. However, if you don't have the time or patience then its time to find an experienced Porsche Tech nearby you.

In the mean time, read The Mr. Ice Project
You will find the article helpful

[Newell33]

The refrigerant was added with the car running at idle, and with the lid up. The guage on the can was right at the low / normal line when I hooked it up. I added just a bit to get it into the normal range with the car idling in the shop (again, lid up). Thanks for the info on the blower. I'll do a little more diagnosing with the correct equipment and go from there.

[Newell33]

Great article! That will be a great start. Thanks kuehl!

[wwest]

Originally Posted by Newell33

Hi Guys

I have a question concerning the A/C on my 1986 Carrera. I haven't had a lot of time to diagnose, so I'm really just looking to help narrow down my problem. The A/C currently does not blow any cold air. It has been converted to R134A at some point in its life. When I first got the car I turned on the A/C on the console only to find that the compressor was not kicking in. I decided to purchase one of the "all in one" A/C cans with the guage and proceeded to top off the system. When I hooked up the can I noticed that the system was just on the "needs filled" threshold. After topping off the freon the compressor now kicks on, but I don't have any cold air.

After a little review of the system, I did find that the blower for the front condenser is not working. I have power to the blower when the A/C is on, but the blower motor doesn't spin. I know that this will certainly affect the temperature, but one thing I noticed is that the vent temperature doesn't seem to change whether I'm driving down the highway, or sitting at a stop sign in town. If the rest of the system is operating properly, wouldn't I at least feel some cold or cool air driving down the highway with the air passing over the rear condenser? I realize that I should probably get the system checked with a set of guages, but I wanted to at least determine how much of an affect the front blower has on the system.

Thanks in advance for any insight!

On a side note... If anyone has a good used front blower for sale, please PM me!

Josh

"..compressor was not kicking in..."

"..after topping off the freon..."

With the factory system intact the compressor would run regardless of "freon" charge level, it only depends on the thermostatic switch that detects the evaporator "excessive" cooling level to switch the compressor off.

It sounds as if some previous owner not only converted to R134 but also added a refrigernat pressure hi/lo compressor control switch. That will be near the compressor low side connections to interrupt the compressor clutch circuit.

Assuming the compressor is now running, or cycling on/off in accordance with the 2 control functions, yes, you should have cool air coming from the center vents.

It sounds to me as if the blower in the smuggler's box isn't working. That's the one that moves air over/through the A/C evaporator to provide cooling.

Personally I wouldn't worry much about anything getting into the system, having refrigerant that is ALWAYS under pressure leak out is NOT the same as atmosphere, or atmospheric mositure getting in. Even <1 PSI of remaining refrigerant would prevent that.

But yes, the conditions under which you use the aftermarket product to recharge the system are well defined in the previous post. But...provided the front lip blower is working you can get by with the engine lid open.

Or you could go ahead and add two 12 volt auxillary cooling fans for the engine lid condensor as I have suggested elesewhere.

[zippy_gg]

If your 86 is anything like mine you will find that your evap motor is just as seized as your front condenser motor, just as wwest suggested.
This means that even if everything else was brand new you would not be getting any cold air through the AC vent.

[Josh D]

Originally Posted by wwest

"..compressor was not kicking in..."

But...provided the front lip blower is working you can get by with the engine lid open.

Not where I live, unless in the dead of winter! I opened the lid on mine with guages on it while running and my discharge pressures where climbing above 300psi pretty quickly! That was at 90* ambient.

[brads911sc]

Not with ambients above 90 unless you want to blow a hole in your condenser due to high pressure...

Still selling Spal fans i see. this is not a solution for every AC problem on the planet. In fact it will do little with ambients over 90. LOL Some of these issues do actually require some thought.

Originally Posted by wwest

But...provided the front lip blower is working you can get by with the engine lid open.

Or you could go ahead and add two 12 volt auxillary cooling fans for the engine lid condensor as I have suggested elesewhere.