4ocious

Since I'm relatively new to 911TT ownership I don't have a lot of experience with the air conditioning now that it's getting warmer here on the east coast. My car is a coupe and the A/C doesn't seem to cool very effieciently, effectively or consistently when it's set to "auto" i.e. on occasion it will even blow warm air. Is this normal? I don't know if the coolant has ever been checked and now that the car is 5 years old is this something that should be looked into? Thanks.

jhbrennan

I'm in Texas and A/C cools just fine. Probably should have your's checked.

dianic

what is the temp setting that you have?

4ocious

It's set at 72 but in order to get it reasonably comfortable I manually set it to 68-69 and even that doesn't do too well.

dianic

I am pretty sure that you need a freon charge... It doesnt sound right. When working properly, and assuming that the car is not parked in the sun (where for the first few moments its normal for the air to be warm) it should be pretty cool inside very quickly...

Macster

A cooling system that has the right level of coolant and can hold pressure is critical to the engine's health. Less much less so to the A/C system and its performance.

Regardless if the A/C system is suspect or not, you should check the coolant level (cold!) once in a while.

There's a possibility air flow through the radiator ducts has been affected by a build up of trash (mainly plant debris) that collects in the radiator ducts and between the A/C condensor and the radiator that sits behind this. While this may not affect the engine's running temp (at least to the point the engine too hot warning light comes on) it can affect the performance of the A/C system.

The 'fix' for this collection of trash is to remove the front bumper cover and clean out the radiator ducts/between the condensor/radiator.

Once thoroughly clean then a preriodic cleaning with compressed air or a leaf blower can keep the build up down. I have my Turbo's oil changed every 5K miles which comes around several times a year. Each time the tech blows the trash out of the radiator ducts.

Anyhow, the auto climate control system can blow warm air from mainly the vents under the windshield to keep the glass from fogging up from being too cold in warm/humid conditions.

If the system is truly blowing warm to hot air that is not part of the autoclimate and the normal varying of temp and vents to keep the cabin temp at the 72F setting the system can be low on refrigerant.

You can have the system checked out. What this involves is the system is connected to a machine that will remove the refrigerant/oil and pull a vacuum on the system for IIRC 30 minutes to remove all this. It also gives a chance for any leaks to show up.

Then the system is refilled with the proper type, amount of refrigerant and oil pump. The system is tested to ensure all is well and there are no pressure leaks.

If leaks are found they have to be fixed.

If you continue to drive the car use the system if it is low on refrigerant this can ruin the compressor. The oil this needs is carried by the refrigerant. If this doesn't flow in sufficient amount through the system the pump essentially runs dry.

There is a DIY test, but I caution you you really need this system checked by an expert. If you insist I will post the steps by which you can determine to some level if the A/C system is working ok or it is suspect.

The test is for a 996 Turbo but the steps are probably the same for the 997 and its A/C autoclimate system as are the cooling numbers.

Sincerely,

Macster.

Terry Adams

Thanks Macster.

Our Lexus IS 350 has been leaking coolant and oil mix on the garage floor. Intermittent, about every third short trip. About 1/2 cup combined each time.

At first I thought they were unrelated leaks. Water from the AC condensation - normal - and oil perhaps from overflow on a recent oil change our son did at Jiffy.

Making appointment with the Lexus dealer today.

4ocious

Thanks Macster for your excellent informative post! I'm taking the car in Thursday for a complete A/C check-up. BTW, I also checked the other items you mention and found no issues.

rrm

I also am in central Texas and can attest to the fine cooling the 911tt a/c puts out. It favorably compares to a ZO6 I had a couple of years ago that would freeze the passenger even with the temp being 110 outside.
Really a good system...rrm

planoturbo

I own a a/c company and agree for the most part with the posts. If the a/c system is low on refrigerant it should not effect the engines cooling, but could shorten the life of the a/c compressor. I would also check the cabin air filter. If it's real dirty it can restrict airflow. I live on Texas and agree the a/c system does work very well when operating properly.

See Ya,
Steve

yemenmocha

Assuming we have same A/C but my 6yr old Carrera's A/C blows too cold at the lower number settings so I always set it mid 70's to be comfortable. The temp inside gets down fast, especially if the car is moving (no stop and go traffic).

You should have this problem too.

atcbi5

If all checks out with preasures, Freon, Oil, etc, next thing is the A/C control unit. It has a small fan at the back of the unit itself. This fan samples air temp via a sensor. Sometimes the sensor's fan quits and this will cause the unit to malfunction. A new one is about $600.00. It has to be coded so dealer visit more than likely.

4ocious

I recently replaced the cabin air filter so that's not the problem. I hope it's the temp control unit because that's covered under my warranty. I'll know and post a lot more tomorrow after my visit to the Porsche indy I'm going to.

4ocious

My indy found no visible reason why my A/C was not cooling correctly so I had the system evacuated. As I thought, it was low on refrigerant and had not been serviced since new. My A/C works fine now. Thanks for all your responses!