911purist

So we're just getting into summer, which is great and usually more fun when you go out for a drive in most parts of the world, unless you live in Dubai or somewere similar. Its mid day end of May now and temperature is currently hovering around 42C / 107F . This can easily hit 50C / 122F by the time we are in July August timeframe!

So the question is this, apart from the regular maintenance for my 1999 C2 996's AC, is there any way to make it run cooler than what it was designed for? Any aftermarket parts that could help? Would appreciate feedback from anyone who's done any kind of upgrade to a 996 AC.

Gonzo911

Have you had your car through a Dubai summer yet? I live in Arizona were our summer temps are usually over 110F for a good part of the summer. My car rarely runs hotter in July than in December, although the engine deck lid fan runs more often. Standard set up, no third radiator, etc.

Zanzibar Red 996

The question was about A/C
Not the running temp of engine

Gonzo911

I should never post before 8am!

Imo000

Is everything in your system up to spec? Rads and condenser clear of any debree, evaporator clear of any dust, etc?

kromdom

Not aware of any aftermarket mod to the AC to make it run cooler. Meanwhile, items below might help:
1. when was the last time radiator was cleaned?
2. coolant flushed and filled?
3. refrigerant recharged?

Macster

How does the A/C perform in that heat? Both my 02 Boxster and my 03 Turbo have been in up to 118F heat and while for instance in one high heat event in the Turbo going from Flagstaff west on I-40 past Kingman and over to Needles CA and beyond the glass was hot to the touch the auto climate temp was set to 72F and the cabin temp was quite comfortable. More than once after noting the outside temp display on the dash of my Turbo I'd have to glance over at the A/C display and was pleased to note the cabin fan speed was not even at the halfway point. The A/C was able to maintain cabin temperature in spite of the heat and blazing sunlight without having to blast air into the cabin.

In short you may be trying to fix something that ain't broke.

For upgrading the A/C I'm not sure what you can do, easily.

More pressure at the compressor could aid cooling but the system at times already operates at its highest (safe) pressure so to get more pressure you'd have to upgrade to a different compressor and then worry about the system holding this pressure.

More cooling capacity at the front would be needed too. The condensers have to remove the heat compressing the refrigerant creates.

Bigger (more surface area) condensers are probably out of the question so you are left with increasing the air flow through the existing ones. Under some high ambient heat and A/C load conditions the fan speed gets bumped to high so you'd have to find fan motors that run at a higher speed and of course find fan blade/hub assemblies that could take the higher speed safely.

Best I think would be for you to ensure the radiator ducts are clean, clear of any debris and the condensers and radiators are clean and free of any grime that can interfere with cooling.

Be sure both fans are running and switch from low to high when they should.

Keep the cabin air filter fresh.

As best you can avoid letting the car sit in direct sunlight and thus build up a big heat load that has to be removed by the A/C. Even if you have to park the car in a parking garage out of direct sunlight and walk a bit to where you are going I think is better, though of course there's your comfort to consider.

Be sure the car's engine cooling system is in tip top shape. The coolant tank cap can be the source of a coolant leak and if the coolant tank is "old" it can be at risk of developing a crack that can turn into a severe coolant leak at any time.

Inspect the water pump for any sign of failing seals. A bit of coolant stain is ok on the pump flange but the stain size should be small and there should never be any sign of wet coolant.

Also when the engine is cold and off check the serpentine belt for any signs of sharp edges developing. This can be an early sign an accessory drive is developing play in its bearings/shaft and in my experience the accessory drive guilty of this is the water pump.

Oh, you might consider window tinting in your situation. Cutting down on the amount of infrared energy that gets into the cabin can only help the A/C perform better.

wwest

Other than window tint...a MUST!

Temporary, QUICK, fix..!!

1. Turn the system down lo the lowest setpoint, MAXIMUM cooling.

2. Use the recirculate mode ONLY.

3. Use the blower speed to moderate the cooling level.

To avoid exterior windshield fogging in a HUMID climate always CLOSE the windshield defog/demist/defrost airflow path.

The above procedure will bypass the system's reheat/remix airflow path and as an added benefit the FE will improve slightly and the engine might run cooler due to the lower heat loading on the radiators.

Long term fix.

In the US I would suggest going to home depot and buying/installing a manually operated water flow shutoff valve to install in the coolant line flowing into the heater core.

911purist

Hey Gents,

Thanks for the feedback, much appreciated. To answer a few questions / points;

I've had the car for almost 2 years now, I've had the AC checked / maintained by a specialist and have used it all last summer and almost throughout ever since. It’s not that the AC doesn’t cool, it does, it’s pretty decent, but in peak summer / mid day, it barely cuts it.

Maintenance done included cleaning, coolant flushing and filling, as well as change of belts. Fans are running fine.

Engine cooling system is running fine, no signs of leakage / loss of coolant, or running hot. Will double check water pump.

I have had tinting windows on my to do list so that is a must. I'll pull out the tool box for that radiator / condenser cleanup job this weekend.

Would adding a 3rd / center radiator help? I know it would with the running temp but any impact on AC?

Thanks

Macster

Don't see how adding a 3rd radiator would help the A/C. The condensers are located ahead of the radiators so the condensers already get the as cool of air as there is.

You might look into an aero kit for the car. I'm thinking one that comes with a front air dam that reduces the amount of air that goes under the front of the car.

These generally help air flow when the vehicle is moving through the radiators as they lower the air pressure under the car.

For an example look at the front air dam of a 996 Turbo. The one on mine hangs down really low.

If you enjoy high speed driving though you want a kit that is balanced front and back. I'm always loathe to slap a big old air dam on the front of the car without proper modification at the rear of the car to balance downforce so the overall balance of the car is kept the same as stock.

Without access to a wind tunnel you will have to rely upon the reputation of the company to know you are getting a good system one that offers real aerodynamic improvements other than simply stating it does on the box.

The only company that I know of off hand that I would rely upon is TechArt.

See link:

http://www.techart.de/en/techart-sho.../exterior.html

My info is when a company sells something that it claims offers aerodynamic benefits it has to provide something to back this up, like I guess how the pieces/parts decrease lift or increases downforce.

If this holds any interest for you you'll have to do your research, see what's available, and what it claims to offer.

There might be some benefit to fitting an overdrive pulley to the A/C compressor.

But where you would get one -- other than having one custom made -- and what the ramifications from doing this are I can't say.

911purist

Macster you are a data bank, I like your thought process! And agree on all points, but honestly, if it hasnt been tried and tested, I'm not gonna take a chance with a custom pulley. Same concept as with the aero kit; either its all from a reliable brand which has been tested and works well together, or keep things stock.

Appreciate all the feedback, I'll do the radiator / condenser clean up and the tinting and take it on from there.

Thanks

Hal

In the air cooled world, Griffiths is a well respected a/c vendor. I notice that on their website, they mention 996 parts. I have no idea if they will help your situation, it is probably worth a call or email to hear what they say. http://www.griffiths.com/porsche/

wwest

I have little doubt that tinting the windows, rear especially, wille of great help, maybe even "enough" help.

Modern day automatic climate control systems, 996/997 inclusive, are as much about avoiding driver and passenger DISCOMFORT, as they are about COMFORT.

With my 2001 RX300, or even my 1995 LS400 I find I have to interact with the system manually in many situations.

In the wintertime in order to bring the cabin up to a more comfortable temperature quickly I turn the setpoint up to maximum heating (blower follows as does footwell ONLY air outflow) until the cabin reaches my comfort level.

Then I switch it to fully automatic but ALWAYS disable the A/C compressor. My '01 C4 has an added switch to open the compressor clutch circuit throughout the winter period.

In the summer the opposite is true, the system initially gets set for maximum cooling...

Capt. Obvious

When you tint the windows, spend the extra money for ceramic tint, this will significantly reduce the amount of heat in the car from the sun's rays.

Imo000

There is no aero kit or smaller electromagnetic clutch for the compressor, on the planet that will make the factory perform any better than when it came off the assembly line. The system is limited by the evaporator inside the cabin. Therefore, this is as good as it gets.