Air Conditioning Problem II

[tdf2001]

Today for the third time I noticed a problem with the air conditioning. In rare cases and after one year of ownership and 20,000 miles later I have noticed the first problem with my CX-7.

I went on a 4h interstate drive across the Midwest in 90+ degree weather today. After about 3h of 75mph cruising, fog (eek2) would come out of the right middle air outlet. While driving I turned the air off, waited 2-3 minutes, and turned it back on.

At this point the air conditioner reduced its fan speed all the way down but would still blow some cold air. After getting home and letting the car sit for 1-2h, all returned to normal again.

What conditions cause the fog to come out of vents? Naturally, it was a hot and humid day today in the Midwest but not out of the ordinary for this time a year. Has anyone else experienced this? I did read the other thread with regards to this, hopefully this new one stays on topic...

 

[Zoom49]

What conditions cause the fog to come out of vents? ...

The fog is actually water vapor. The cooling coil is so cold it causes the
humidity in the air to percipitate in to the vapor you see. Running the air conditioner for prolonged periods with low fan speed can cause the coil to freeze over with moisture further reducing air flow. Shutting car off at the
end of the trip allowed the frozen water vapor to melt off the coil allowing full
airflow to return.

Steps to lessen chance of coil freezing
1) Manually select a higher fan speed
2) Use recirculation mode in lieu of fresh air in high humidity

Step to defrost cooling coil
1) Turn off A/C but keep blower on for 4 minutes. The warm air blowing across the coil will melt the ice.

 

[ghost_rider]

Has anyone else noticed that when the car has been sitting in the heat for an extended period that it takes the AC forever to get cool?

 

[07LiquidCX7]

^Yes. But that is normal with 4 cyls. Never had a problem in any of my BMW's inline 6 cylinders and my Mustang's air was insane from the get go because of the V8.

 

[koala]

It was 30-37 celcius here for the bulk of July, and my car sits out in the sun at work... whenever I jumped in to leave the A/C always blew cold very quickly... after 10-15 seconds maybe?

I know I have a lot of complaints and problems with my CX-7, but I have to say the a/c has been awesome.

 

[tdf2001]

Steps to lessen chance of coil freezing
1) Manually select a higher fan speed
2) Use recirculation mode in lieu of fresh air in high humidity

Step to defrost cooling coil
1) Turn off A/C but keep blower on for 4 minutes. The warm air blowing across the coil will melt the ice.

This makes a lot of sense. Thank you! After I saw the fog, I did turn the air off and went to manual mode a couple of minutes later. This took care of the fog bit I could not get the fan to rev up to actually blow a lot of air. For the rest of the trip, the air conditioner would provide cool air but with little air actually blowing out of the vents. From what you wrote, it almost sounds like the fan overheated and turned itself off or on low.

 

[Killer]

^Yes. But that is normal with 4 cyls. Never had a problem in any of my BMW's inline 6 cylinders and my Mustang's air was insane from the get go because of the V8.

This makes no sense whatsoever. The compressor for the AC is belt driven. All engines whether 4, 6 or 8 cylinders Idle and rev at the same RPM's (Roughly). So the compressor (Which feeds the AC Coil with refrigerant ) turns at the same speed. The amount of cylinders has NOTHING to do with AC Effectiveness.

 

[hevysrf]

4,6 or8

This makes no sense whatsoever. The compressor for the AC is belt driven. All engines whether 4, 6 or 8 cylinders Idle and rev at the same RPM's (Roughly). So the compressor (Which feeds the AC Coil with refrigerant ) turns at the same speed. The amount of cylinders has NOTHING to do with AC Effectiveness.
We all know that 6 and 8 cylinder engines have more torque at lower rpm, and the faster you turn a compressor the more torque it takes. So, it is quite possible that a 4 will have different size pulleys and the ac will turn slower at at given rpm.
I am sure that the CX7 computer also cuts out the ac under hard acceleration. MartyD

 

[koala]

The strongest A/C I've ever had was on a 4 cylinder (my '01 S2000 and '04 S2000) both had incredible a/c. (instant freezing cold air, and they blew HARD).

Siginficantly better than the a/c in either of the F-150's I've owned. (both 8 cylinders with massive torque).

I'm not so sure the number of cylinders means much when it comes to the cooling potential of your a/c.

 

[offset_98]

I've seen this on my '87 Aerostar, '96 Explorer and '98 Expedition...cylinder number has nothing to do w/ it. It is the humidity and don't worry b/c its nothing to worry about.

 

[07LiquidCX7]

The strongest A/C I've ever had was on a 4 cylinder (my '01 S2000 and '04 S2000) both had incredible a/c. (instant freezing cold air, and they blew HARD).

Siginficantly better than the a/c in either of the F-150's I've owned. (both 8 cylinders with massive torque).

I'm not so sure the number of cylinders means much when it comes to the cooling potential of your a/c.

My wife's old Civic had the EXACT same A/C problems. And they aren't even problems, they just take awhile to get cold. Neither my BMW or mustang had the issue. I'm sure it has to do with the compressor Mazda uses or something but... we may never know.

To the guy who said it doesn't make sense. Now I'm sure there are other contributing factors to this mystery such as the actual compressor Mazda uses, or something like that, but from personal experiences... the more cylinders, the quicker the AC gets cold. It was a generalization, not an explanation, so don't think I am saying ALL 4 cylinders vehicles experience this issue. Just that it's a common problem with alot of them.

 

[stick]

hey guys im new but i just bought my first mazda and it was the CX 7.
ill introduce myself later but just to add to this topic is that honda/acura are known for their AC systems just like their hi reputation in the shifting department.

so far im pleased with our CX7 AC unit altho we havent been in it long, got it with 8 miles, but it seems to be working great in near 100 degree temps.

 

[07LiquidCX7]

^Stick, welcome. They aren't horrible by any means. You only have a problem when you park the car in direct sunlight for a couple of hours and then try to get the AC going. Here in SA we are always near 100F so the wife and I just try to park in the shade. No big deal really. It's just an annoying thing you have to learn to work around.

 

[mikey1981]

not throwing gas to the fire, but whoever said that 4 cyl take longer to cool?? whaaaaat? the best AC i have ever felt has been the unit in my 2005 Honda CRV hands down strongest HVAC ive ever come across. Thing is throwing cold air/hot air within in a couple minutes wheenver its turned on. Ive never had a single issue with ac cooling from my very first car - 95 Accord 2 Door. Worked perfect over 200k miles. My RDX now contiues the trend of my CRV, incredibly strong and efficient cooling

 

[erhayes]

With my CX7s long black dash and large window, I found that the two piece window reflectors help a great deal.

 

[07LiquidCX7]

where do you live Mikey?

In San Antonio in the summer it is routinely 105+. And not a dry heat either. That's the only problem here. AGAIN, I was saying (I should have clarified) that the 4 bangers I've been in (99 Honda Civic, 2007 CX-7, 96 Honda Accord, 89 Honda Accord) take consistently longer to cool on a hot summer day than my BMW and my Mustang.

 

[tdf2001]

Back on Track?

I am the OP. Does anyone have any input as to why this is happening and what could be wrong with my AC/fan?

 

[ljmattox]

Just posted in another section, I had an a/c problem yesterday on the interstate, near 100F and it stopped blowing cold air, and much air at all.

After having dinner, and resuming, it worked fine on the way home.

There's a TSB that addresses the problem with CX-7s with a build date before 9/06 (like mine). Found it posted a few times on this forum, search "air conditioning" problem and it turns up.

HTH.

 

[koala]

I am the OP. Does anyone have any input as to why this is happening and what could be wrong with my AC/fan?

http://www.mstore2000.com/PDF_Files/07-004-06-1700.pdf

 

[tdf2001]

http://www.mstore2000.com/PDF_Files/07-004-06-1700.pdf

Absolutely fantastic! Here is my one problem and it's already documented and easily resolved!