Mac

My '95 has suboptimal cooling at times. Here in East Texas, the heat and humidity are stiff demands but my wife's S320, and my prior RX7 did better than my 993. Have mounted a digital thermometer in the front outflow vent, and with the blower on full and recirc on (on a typical July day, same time of day and temps during summer are unfortunately very constant) will notice sometimes good cooling and temp down to 47F. Sometimes, after extended driving, it will climb back up to 57-59F, and the car is clearly not cool enough inside. I saw in the archives (yes, Ray, I looked) that someone in Miami had their evaporator sensor relocated and a similar problem resolved. First, does this sound like that, and second, where is that sensor and where do I move it? (checked the shop manuals, and, as usual, I find them less than helpful).

Thanks, Mac (sweating in Texas)

Robert.

I'd be interested in hearing any suggestions too. I am in the panhandle of FL and am experiencing the same problem.

This is my third Porsche and none of them provided the same degree of cooling that my wifes car or my truck does. Is this something I'm just going to have to live with in extreme heat/humidity?

Thanks,

RHM

STLPCA

Yes! It'll never cool as well as an American or Japanese economy car. You should try my black/black coupe on a St. Louis day like today (100+ w/high humidity).

P.S. The 996 does better.

Pete911air

Mac,
The A/C condensor fan has a two speed fan. Porsche has a problem with the fan resistor and if one of the stages is not working your A/C will not work efficiently.

Pete.

Ray Calvo

Mac, I'll go along with Dan's comment. Air-cooled 911s just don't have the evaporator size and air flow needed to cool the car like a Detroit-based product (or my Audi A4, for that matter). 993 is far better than old '84 Carrera (surprisingly, about matches dealer installed unit on old '76 911), and good enuf for Steelertown weather, but I wouldn't want to count on it keeping me cool if I was in a Houston or Tampa summer day.

However, your temperature variance doesn't seem right. Bring the car in and have it professionally checked. I have topped up the R134 refrigerant (successfully) myself on the 993, but wouldn't recommend it to anybody else. Seems old-fashioned top-ups based on measuring compressor discharge and suction pressures (or even using a sight glass) are verboten per the shop manual (they talk about a total purging and recharging).

Ran

I find the AC quite a bit more noisy in "MAX" mode. In the regular mode, it is reasonably quiet but not as great cooling wise as on my M3. I dont think even the MAX equals the M3 airconditioning (any BMW owners care to comment to compare notes on what is normal in a 993) but its pretty cool though noisy. Its also my only complaint after a few months of ownership as it distracts from enjoying music or enjoying the car sound. Thus, I dont enjoy it as much in over 95 degree days as I do otherwise.

911-TOUR

I'm going to have to post a different opinion...I have no problems with the A/C in my 1995 993 even in the high heat + humidity of Houston. To be honest, I was worried about this when I moved from CA a few weeks ago, but the A/C has been more than adequate. I rarely turn my fan speed up past 3, and with Max A/C and recirc on the thing screams like a tornado (not to mention rapidly cooling off the cabin) In fact, I sometimes have to turn the AC down to prevent condensation on the windshield.

No complaints here...

sean

Pete Lech

I always keep a thermometer in the center vent of my cars, and my 993 runs a consistant 40 degrees after driving for 10 minutes or so, no matter what the fan speed. So far, I haven't had to use higher than 3 however. 47 degrees is too high, and indicates something is amiss, IMHO.

My "amurrican" cars typically ran closer to 35-38 degrees, plus have a lot of vent area. The best of the lot is the '95 BMW 525i however, which has a lot more vent area, so it can cool without a lot of noise of rushing air.

Mac

Yikes! Sean (in, of all places, Houston) has no problem then I should definitely be better here. For the non-Texans, Houston defines HOT AND HUMID. Hmmmmm, I've checked the compressor pressures and they're normal. Have washed the bugs out of the front coils as well. If 47F is too high, then I'll ask the dealer to check it out AGAIN. Anyone else measured the vent temps???

Ray Calvo

Mac, one cheap check. Is the condensate drain clear? This is the hole under the car where the condensed water is drained out. If it is blocked (even partially), could allow water to build up around the evaporator and block performance, Generally, this causes a mist to come out of the vents, but the symptoms you have (good performance initially, then gets worse with time) makes it a possibility.

You should be getting a fairly regular stream/dripping of water out the drain if AC is going full bore on a hot humid day.

Mac

I haven't checked the discharge yet, excellent idea! Thanks to all, and still wonder about normal range for vent temps if anyone else has/can measure theirs that would be very helpful in trying to get the dealer not to blow this off. M.P.

PETER

My 95 993 does not cool well once the interior gets warm in the Houston heat.

Where do I find the drip line? Will I have to pull a bottom pan off? Can I simply clean it out with a small pin or stick?

Any advise appreciated; the car sure gets warm when the temps are 90 plus.

Ray Calvo

Peter, oh brother!!!!!!

Turn on the engine and A/C, run it at full blast, then look under the car and see where the condensed water is dripping down from. Might take a few minutes for the water to start showing from a cold start, but you should have a pretty good stream if you pull car into garage after a drive. Guess what - where the water is dripping down from is the drip line discharge!!!!! I would bet it's up around where the firewall is, in back of the front tires. I don't know exactly the location - sorry.

I haven't had to work on this on my 993, but on my old '84 there was a little rubber flapper valve about 1/2" in diameter protecting the discharge and was flat with the car underbody. Road dirt had sealed it to the body. A little scraping with my fingernail between the flapper and the car underbody and some scrubbing around it with degreaser got the discharge line clear and the AC working again - well, as well as it did ever work on this 911. I don't think you'll need a matchstick or toothpick - line is about 1/4" inner diameter, as I remember.

911-TOUR

All,

On 993's the A/C condensate filter may have never been opened at the factory. (it's a little rubber flipper as described above) If this is the case, you must open it for proper cooling. I found this out when going through the PPI for my '95 - it seems that the previous owner had almost never used the A/C - could also be the reason why mine seems to be so unusually cooool. In any case when the mechanic and I opened the filter, we drained 2 quarts of water !! I'd hate to think what this might do if left unchecked, as the overflow is right onto your feet under the dashboard !

Just a little more info that I remembered reading the previous posts.

sean

cecil

Mac I had the temp sensor relocated on my car. I'm in Tampa. The temp sensor was at the top of the evaporator and the system was icing up. If this was your problem you would have no cooling after it iced up. It was only doing it on the highway. Moving the sensor fixed it.