1989 Carrera - A/C assessment

[73pcar]

I am considering a low mile 89 Carrera, and it seems that this forum has endless posts about upgrading the factory unit on this era car. Are the various upgrades really necessary, i.e. is the factory system (assuming its original parts are working as designed) that awful? I am in the mid-Atlantic area so we certainly have hot and humid weather in the summer but the car would see infrequent use only...but I want good operation of the A/C. Obviously I don't expect it to perform to the level of later model Porsches. Thoughts from those still using the factory system (happy or suffering!) would be really helpful. Thank you.

[FrankM_]

I have a perfectly maintained 1985, however the a/c had some small / slow leaks that I wasn’t able to find. Apparently the original hoses do not keep the R134a gas inside. I did blow cold for one to two months though but then the charge was gone.

I did a replacement of the hoses, front condensor and evaporator (all Griffiths) and since that moment it is an adequate airco for where I live (Belgium, not hot/humid for mist part of the year).
At 30C in summer it takes less than 2 min to blow really cold air, after about 8 minutes the temp in the cabin is ‘under control’.

If you really have a humid climate too it might be advisable to add an extra condensor (or two).


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[darrin]

the main problem you're likely to run into is system integrity from the factory. The non-barrier hoses used up and down the length of the car slowly leak freon and, especially given its age, the car's a/c system integrity is likely suspect (even if it were to "blow cold" after a refrigerant top-of) . So, you'll at a minimum likely require a new "barrier" ac hose set and a replacement drier. Once you're in there, you might as well also upgrade the front condenser and evaporator unit with those sold by Griffiths. While I suspect adding Griffiths driver's rear wheel well condensers and other goodies will similarly up the game, I've been very happy with simply replacing the above here in (much drier than mid-atlantic) Denver -- regardless, a 80s Carrera's Ac system isn't going to be great -- heat sink is going to be your biggest enemy, so parking in shade and/or putting up windshield screen, etc. helps.

[isby]

Agree with the posts above. I just installed a Griffiths package on my '84, but left the original front and rear condensers. Personally, I don't think upgrading those factory units gets you much bang for your buck (unless there are leaks, damage, etc.). However, I did upgrade the evaporator, which I think made sense. Also, as others have said, a barrier hose upgrade is almost certainly needed. Of course, even if they are working, you may find the front condenser blower, evaporator blower motor and/or compressor are tired (if original). Ultimately, I decided it was better to bite the bullet and do the whole system rather than struggle with it for years as components gradually fail.

[73pcar]

Thank you all for sharing your experiences and recommendations of what you did to improve your systems.

[darrin]

Isby and 73pcar -- imo, worthwhile to upgrade the front condensor if replacing lines -- as I understand it, our carreras' ac systems are shy on condensor capacity (ability to transfer heat out of system) and griffin's front condensor upgrade increases the capacity of the stock system -- see, https://griffiths.com/product/911-930-kuehl-high-performance-front-cond/

[GH85Carrera]

I have a 1985 that I tried hard to make the factory AC work at peak performance. Yea, it it pretty pitiful if the temps outside are above 85 degrees on a sunny day. If it is cloudy, or at night, it is adequate.

At a very minimum replace the non barrier hoses with good barrier hoses, and replace the receiver-dryer and likely the evaporator.

The big design flaw in the factory system is inadequate condenser area. I live in a hot area, and I take road trips to other HOT areas and I have seen 118 degrees in Needles, CA and 95 degrees and 90% humidity that make a heat index of 147 in Savanna, GA in August. I have driven my 911 in 41 states so far, and plan to get to all 48 lower states.

With the four condenser system from Griffith's, I can stay totally comfortable in the worst heat.

Of all the projects I have done to my 911 in the 26 years I have owned it with no doubt the clear winner is the AC upgrade. I can now enjoy my car all year long, and my wife is happy to ride with me in the summer heat. On a few occasions in the extreme heat on a long trip she will tell me to turn the temp UP because she is cold with all the air vents turned away from her.

[isby]

Yes, definitely agree that condenser capacity is an issue in these cars. I addressed that by adding Griffith's rear fender condenser.

[Tobydog61]

I'm reading that the R134 has smaller molecules and therefore requires a tighter system in order to keep if from leaking. It appears the R12 and R12a which is supposedly compatible with R12 systems, is available. I'm debating on trying to recharge my original R12 system with R12 and see how long it holds a charge.

Any experience with the R12a or would the recommendation be to update the system to the barrier hoses, run the r134 and be done with it.

[GH85Carrera]

Originally Posted by Tobydog61

I'm reading that the R134 has smaller molecules and therefore requires a tighter system in order to keep if from leaking. It appears the R12 and R12a which is supposedly compatible with R12 systems, is available. I'm debating on trying to recharge my original R12 system with R12 and see how long it holds a charge.

Any experience with the R12a or would the recommendation be to update the system to the barrier hoses, run the r134 and be done with it.

You need to use barrier hoses regardless. When new the system needed to be recharged each year. R12 was 50 cents per pound back then.

The old hoses will just leak out any refrigerant you put in.

I don't want to get into a debate about R12a, but I believe you will find it is mostly a hydrocarbon like propane. If you use it, be sure to label it for any future mechanic to know what it is.

https://www.epa.gov/snap/unacceptable-substitute-refrigerants

[darrin]

my concern with R12a and other propane-based refrigerants is that our cars' AC systems were designed to use a non-flammable refrigerant (R12 / R134a). So, think about what would happen if your vehicle is involved in an accident. The front A/C condenser is just behind the front bumper and contains high pressure refrigerant vapor and liquid. If the condenser is ruptured in a frontal collision (which it often is), high pressure flammable vapor will be released, increasing the risk of an under-hood fire.

[Tobydog61]

Great info, thanks. I have a full list of maintenance planned for this winter. May try to charge with R12 in the spring to see if it gets me trough the summer and then updated hoses next winter. Man the list just keeps growing on this car.

[darrin]

Originally Posted by Tobydog61

Great info, thanks. I have a full list of maintenance planned for this winter. May try to charge with R12 in the spring to see if it gets me trough the summer and then updated hoses next winter. Man the list just keeps growing on this car.

if you have ac gauges and/or are planning to get gauges to do the R12 charge, you might want to start with inert nitrogen and see if the system will hold pressure with nitrogen before blowing R12/CFCs through it

[Buckeye]

I have an 1987 which I have had for 11 years. I had collected 25 lbs of r12 and for the first 6 years of ownership I would put around 6-8 oz of r12 in the system in order to get the correct pressure in the system. The system did work and blow cold air through out the summer. At that time I lived in Augusta Ga which has extremely hot and humid summers. Four years ago I replace the hoses, front condenser, evaporator, evaporator fan and added a rear condenser. It was all Griffiths equipment. I now live Florida and it was worth the money to upgrade.

[Coastr]

Don't disagree with most of the assessments above, however some things to take into account with your 89. 1) you have a sanden type compressor and not a york compressor of the earlier models; 2) you have larger side vents in your dashboard that earlier models do not have. I think the safety issues of the propane based refrigerants are overstated as anyone who has tried to light a gas grill in the slightest breeze can tell you. The amount of gas in them is about equivalent to a spray can, not a bbq bottle. However the advise to label it properly is important.

If you want to convert to R134, then you can just re-flll and change the valves, but it's better to drain/flush the system, new receiver/dryer and refill. If you're doing that it makes sense to change the hoses at the same time if you have the budget. And then maybe go for a more efficient evaporator - it depends on how much you want to spend.

It also depends on where you live and what color your car is - the 89 system is not as bad as the earlier systems as porsche did improve it over the years. If everything works and you don't live in a stupid hot area I'd probably start by getting it going with fresh components and see where you are at. You can add extra condensers if you're not getting enough cooling.

Do fix it though - it's there, it might as well be working.

[GH85Carrera]

The gas grill comparison is not real accurate if the car takes a hit from the rear and splits a hose. The full pressure of the system is dumped all at once into the hot engine compartment. A massive fireball will ensue. Unlikely I admit, but very possible and the crash would be bad but a fireball is just adding possible burns to the crash. A gas grill is fed from a regulator and it is slow flow.

In the end, we all drive around with up to 21 gallons of gasoline. It is only really flammable as a vapor and relatively inert as a liquid but still a very flammable product.

Most of us have used a propane blow torch to solder a water pipe.

It is your car, and your risk to use R12a. I will not be using it. Just my opinion.

[thsupernge]

This is such great info guys-love to hear the experiences. If/when I do it I will try and remove the condenser from the deck lid. I hate that thing. Adding more hot air into an already hot engine compartment? I can't wait to get rid of it.

[GH85Carrera]

Originally Posted by thsupernge

This is such great info guys-love to hear the experiences. If/when I do it I will try and remove the condenser from the deck lid. I hate that thing. Adding more hot air into an already hot engine compartment? I can't wait to get rid of it.

All I have is my personal experience. Back in 2007 I was planning a trip from Oklahoma City to San Diego. That meant a lot of miles in the deserts of New Mexico, Arizona and hottest of all, California. The factory AC was pitiful, so I whipped out my credit card, and called Charlie Griffith and ordered his 4 condenser kit.

The only part of my system that remains factory stock are my front and rear condensers. I added the two fender condensers, and all the other parts were replaced.

My cabin was nice and cool and sometimes downright cold, and my engine temps dropped 20+ degrees. A lot of the heat is dumped into the fender condensers and NOT the engine. You will certainly need a bigger front condenser and both fender condensers if you really insist on deleting the engine condenser. Talk to Charlie, and get his input. He knows way more than I do about it.

I love the variable speed fan controller he sells and the LED light for the temp controller to let me know if the compressor is running or not. The hurricane blower moves a lot of air. All these years and many miles later my wife rides with me on long road trips through the hottest places and we stay cool and comfortable.

[thsupernge]

Originally Posted by GH85Carrera

All I have is my personal experience. Back in 2007 I was planning a trip from Oklahoma City to San Diego. That meant a lot of miles in the deserts of New Mexico, Arizona and hottest of all, California. The factory AC was pitiful, so I whipped out my credit card, and called Charlie Griffith and ordered his 4 condenser kit.

The only part of my system that remains factory stock are my front and rear condensers. I added the two fender condensers, and all the other parts were replaced.

My cabin was nice and cool and sometimes downright cold, and my engine temps dropped 20+ degrees. A lot of the heat is dumped into the fender condensers and NOT the engine. You will certainly need a bigger front condenser and both fender condensers if you really insist on deleting the engine condenser. Talk to Charlie, and get his input. He knows way more than I do about it.

I love the variable speed fan controller he sells and the LED light for the temp controller to let me know if the compressor is running or not. The hurricane blower moves a lot of air. All these years and many miles later my wife rides with me on long road trips through the hottest places and we stay cool and comfortable.

Great stuff, really appreciate it! I will for sure!

[73pcar]

Wanted to add my thank you again...tremendously helpful information to my original post. Thank you!