Magnesium

2nd day of driving the nice 8 around. It was a little hotter day today so I needed to turn on some air cruising around town. The A/C seems to work fine for a little while, then starts cycling cold/warm/cold. It cycles so fast that it keeps me from getting hot, it just doesn't cool me down like I am used to. Nobody here can tell me that this is going to be normal because sometimes it is fine, sometimes it's not. I have a feeling that it has something to do with the 65% cutoff for power, but shouldn't be this sensitive being I am still driving like grandma during the breakin period... Any suggestions?

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XK4

The RX-8's A/C seems to be sub-par, at best. Tinting your windows will help a lot. I've been driving around the D/FW area for the last four days with the A/C fan set to "2" and have been quite comfortable. Prior to tinting I needed "3" or "4" on the fan.


Dave

Magnesium

I am thinking that maybe my A/C is undercharged or overcharged. Dealer here I come...

sferrett

So I'm interested if the trip to the dealer yielded any results on the quick a/c cycling. I picked up my black sports '8 a couple of weekends ago and one thing I've noticed is that the a/c seems to spend about as much time blowing tepid air as it does cold air...

Curious if the dealer did anything and if it resolved it or not.

Cheers,
Simon.

dcfc3s

I had a thought about this the other day...

Part of the problem might be the AC working *too* well. All auto AC systems have temp senders in the evaporator (the "radiator" under the dash that cold freon flows through and blower air goes through - it removes heat from the air). If the evaporator gets too cold, frost will form. This can lead to a sticking expansion valve, frost blocking the fins of the evaporator, etc. So, a temp probe is in there to cut the AC compressor off until the evaporator warms up, then the AC compressor kicks back on.

If the system works too well, it's hovering around the cutoff temperature and cycling constantly. It could also be a hypersensitive temp sensor in the evaporator itself.

My wife's '90 convertible RX-7 has VERY good working and super cold AC, and I have noticed it cycling every now and again. I don't know how pronounced the problem is on the '8. Part of the deal too is the RX-8 uses R-134a as a refrigerant (the ozone-friendly stuff) - only a few of the last RX-7's had 134a. Don't know if that makes a difference or not - an AC system has to be designed around the refrigerant.

Dale

brownchiro

Mine works great. I never have to use it above 1 or 2 fan speed. It is 105 here today. You must keep the AC on recirculate; never on fresh air or you will get hot and cold blasts.

91vert

You should not be getting hot and cold blasts even if the recirc is not on. I agree that something is major wrong with the way they have the compressor setup to cycle. It is coming on a few seconds too late in between cycles, and during that time you get a few seconds of warm air.

I think the A/C in my car absolutely sucks.....and it hasn't even been that hot and humid here in St. Louis over the past week since I have picked it up.

I'm planning on making an appointment to get it in to the dealership to have it checked out as soon as I get some time. I'm sure they will tell me it is operating to spec, but you never know. Maybe they will find something wrong.

msrecant

I agree the AC system seems weak, at least compared to other cars I have driven recently (626, Saturn L Series and my Miata) all of which I would characterize as having acceptable but not outstanding AC. When used in fresh-air mode the RX-8 does not seem to cool well at all.

As noted above, I have also seen that using RECIRC fixes the problem. It provides plenty of cool in that mode which implies that it is not a flaw like improper charging.

Hopefully this is a Version 1.0 bug that will be fixed shortly.

Wing

Mine works WAY better than in my Tiburon. It's COLD on fan 1 and right as soon as I start it almost. No hot cycle. It was 30 C today and sunny no problems.

Shamus

In the 2 test drives I've done on very hot days here the A/C has been flawless AS LONG AS the air is not being pulled from the outside. It has to be recirculating inside air only. This is nothing different than any other car I've owned though. To get the coldest air, just recirculate the inside only.

msrecant

You miss the point. The AC really is terrible when it is NOT on recirc. Last night it was only 80 degrees outside and the AC, in fresh mode, continually cycled every 20-30 seconds from very cold to warm, which did not do the job of keeping the interrior reasonably cool. Not comfey ... you need to try it to believe it.

eccles

I have tried it, and I only partly believe it.

When I run mine on Fresh, I occasionally notice the cycling. It never gets warm but I notice it starting to get less cool, and just as I notice it, it kicks back in and blows cold again. But it doesn't happen anywhere near all the time, and it's happened infrequently enough that I have yet to determine if there's a common thread between the times it does happen, except that it's always in Fresh mode, never Recirc.

It's obviously not caused by excess demand, beacuse it's been 108 degrees here the last couple of days, and my AC has performed flawlessly.

msrecant

Since my AC works fine in RECIRC I have had a tendency to leave it there. It has performed poorly on FRESH the times I have tried it.

I will try living with FRESH for a couple of days and see if the poor performance is consistent or not. My plan is to complain to the dealer when I take the car in for its first service. This will let me complain more intelligently (oxymoron?).

8_wannabe

Same problem here, I've had the car about 3 weeks. Always on recirc, always turned to the coolest temp, but it cycles warm and cool air. It won't blow cool long enough to really cool down the cabin. don't tell me I'm operating the A/C wrong; I know how to set a/c. those of you not experiencing the problem: Good for you, you got lucky somehow. But some of us have got bum a/c units. Can over/under charging with coolant cause this? Has anyone yet had a dealer render an opinion?

pelucidor

On three test drives of different RX-8s I thought the AC was OK in Houston weather. Actually I didn't notice it because I was more interested with how the car drove.

Now that I own an RX-8 I will say that the AC is buggy for sure. On RECIRCULATE mode it is poor, on FRESH AIR mode it is even worse - I only use recirc mode. On recirc I find speed 1 is too faint to feel at all (face vents only), at speed 2 it is too strong and the cold air cuts in and out continously every few seconds (gentle driving at 3000 rpm). Temp is always left at lowest setting. Even my 120k mile '91 Integra had better AC behavior, and all 5 of my new cars since then have been vastly better.

After I got my Huper Optik tint things are better (double the heat rejection of other tints) as I can leave it at speed 1 after the car is cooled down a bit. But it is a major flaw for those in hot climates like Texas.

rx8racer

I just talked to my dealer about the AC cycling problem. He called the Mazda "tech line" and was told that this is "normal." The car is programmed to cycle the AC on and off. He said that Mazda acknoledged that they have received comments about it but they are not getting "complaints." They did not give a reason for this. (improve gas mileage I'm guessing) He also commented that when set to fresh air, it will cycle more than when set to recirculate.

Mazda would be able to fix this with a quick update to the ECU if they wanted. If everyone starts complaining about it, maybe they will fix it. I think it is stupid to run the AC at 50% when you are sweating to death! I'm considering hard wiring my own switch to override the ecu control.

msrecant

Agreed! I have a service appointment at which point I will lodge a "complaint".

rx8racer

I did a little experiment with my AC last night. It was annoying me to death listening to the clutch kick in and out while I had the car idling with the air on. Here was the test:
I started the car and let it idle. I turned on the AC with fan speed 1 and fresh air on. The clutch kicked in for about 30-45 seconds then it continuously cycled on and off about every 7 or 8 seconds. This is very annoying and would be very hard on the clutch. It also doesn't cool nearly as well as it could. Does everyone experience similar results when idling? I think it does the same thing while cruising but it's not as niticable. I also tried reving to 2-3000 rpm and the same thing happens.

Zoom49

Yes the clutch cycles even at idle with the interior temp still hot.
This is the reason I dont think it is related to the 65% throttle.
I also connected an A/C guage set and it does not appear to cycle on any pressure control. Tried adding and reducing refrigerant charge with no effect. I believe it is controlled by the ECU or a temp sensor on the coil.

Len

That's exactly what the AC did in my '92 Prelude too. That clutch lasted for > 10 years, so hopefully the RX-8 one will too. The cooling in my RX-8 seems at least a bit more effective than the Prelude.

rx8racer

I made an appointment with the dealer to check it out this week. I want to get my "complaint" logged so hopefully Mazda will fix it someday. I am also going to log my complaint about a loss of power above 6000 rpm and see if the tech can give an explanation.

Wing

I finally noticed this, I was just cruising and I felt my arm get less cold, not hot just less cold.

This is the first time I use the AC on a day that really didn't warrant it. I believe I had it set to fresh air.

It was somewhat annoying.

pelucidor

I will definitely lodge a complaint about the AC - it is so much worse than on any other car I've ever had (Lexus IS300, Acura MDX, Lexus RX300, Jeep Grand Cherokee, Acura Integra, Toyota 4 Runner, Honda Prelude - even cars 10 years old). Heck - it is even worse than Chevy Cavaliers, Pontiac Grand Ams, Hyundais, Mustangs, Sebrings etc I have rented. I only use recirc and it continuously cuts in and out even whilst driving around fairly gently.

jonalan

I noticed there is no mention of any Mazda vehicles.

As a previous owner of several Mazdas, I can say that they have always lacked in the A/C department. IMO - not that this helps or anything.

Spin9k

Here is YAT (yet another theory). I think mine seems to match the symptoms we are experiencing almost to the letter, however.

1. FIRST PROBLEM - OUTSIDE air coming into the car through the vents is HOT. With out the air conditioning on, the air with blower on is way hotter than ambient temp. SOMETHING in the engine passthrough is HEATING the air and it definitely needs more insulation along the way.

2. I belive the RX-8 has what is other cars is called ECONO A/C vs FULL A/C. I have another car w/switch for ECONO vs FULL and the manual says the following:

ECONO POSITION - Use this position when the humidity is low. It is economical as the air conditioner compressor OPERATES ONLY WHEN NECESSARY (caps mine).

FULL A/C - Effective when the humidity is high or when it is very hot. The air conditioner compressor OPERATES CONSTANTLY FOR ADDITIONAL COOLING. (caps mine)

NOTE: I have never been happy with the ECONO mode in the car, always use FULL, as it does what the 8 does, even though the outside air is not superheated in THAT car 1st.

SO when the COMBINATION of an air conditioner that is PERMANENTLY in ECONO MODE (cycling compressor) and HEATED AIR from the ENGINE compartment being used when NOT IN RECIRCULATE, the result is cool, then not cool *almost immediately* as the compressor coils 'lose their cool' due to the hot air. Then the air comes on again... A VICIOUS CYCLING so to speak!!

Why ECONO A/C in our car? Well economy is at issue it appears, maybe a little too much. And so they tried to compensate in any little way possible.

Any one agree or see a problem with this hypothesis??

PS If we could get a shop manual we may find the answer to whether this is in fact... FACT!