Mazda5 - A/C Suddenly Erratic (Mostly Doesn't Blow Cold Air - Then Suddenly Does)

R

reMarkable

Member
I have a Mz5 2008 with approx. 75,000 miles on it. The A/C has always worked very well. Suddenly today at 88 degree F it got erratic. It stopped blowing cold air (just ambient temp air instead) most of the time. As soon as we were convinced the A/C was absolutely dead - then it would give us a cold blast for a 30 seconds to a minute - before it would kick out for another 5 minutes or so. We experienced this with the recirc on and off - and both at highway and city speeds. Anyone have this in their Mz5 before?

I hate to bring it to the dealer for the difficulty getting it there and the obscene pricing. I also can bring it to my local garage around the corner from work, where they are honest and I'm a regular for maintenance. Other facts: I subscribe to alldatadiy.com for my Mz5 and I have checked through the TSBs and whatnot there - haven't seen anything that sticks out. One other fact - I have an extended repair warranty through my insurance with a $250 deductible.

Any thoughts on what it might be and how best to proceed? Thanks in advance.
 
How is the airflow from the vents when this occurs?

Do you have an ear for your vehicle? Is the a/c compressor cycling normally and the radiator fan speed running/increasing as well?

These are the indicators of what might be wrong. If you aren't accustomed to servicing or testing the a/c yourself, I would simply take it to your neighborhood mechanic.
 
flcrusing-
Thanks for the response. To answer your good questions:
- Airflow is fine
- a/c compressor stops when a/c stops running, resumes when a/c resumes
- fan is running fine

As it is - I brought it to the local mechanic, who tested the a/c coolant pressure and ran the car idling w/the a/c for a good long time - and nothing showed up - a/c stayed cold (he didn't charge me - let's hear it for the local guy!) I took it home and continued driving it with the a/c - and discovered the beginnings of a pattern - the a/c would run from a cold start for about 20 minutes - and then cut out AND I could drive without the a/c and it wouldn't work if I tried to start it after 20 minutes or so. Then last night - with the a/c quit, I was parking at home and noticed the temp gauge running high. Sure enough, today on the way to work (with my Torque Android app logging the OBDC data all the way this time) I watched the temp gauge make several runs from its normal position (perfectly mid-way between Cold and Hot) up to about 80% of the way to Hot and back down to almost normal. If it ran hot for too long - the a/c cut out and stayed out for many minutes. I brought it in to the mechanic in this condition and he diagnosed a bad thermostat - nothing directly to do with the a/c - just that the a/c is designed to cut out when the engine runs too hot. Drove it 25 miles since the repair today - seems to have solved the problem. I'll keep a good eye on it for the next number of days - but I think he got it.

Anyone else have to replace the thermostat in an Mz 5 - and if so at what mileage?

Thanks in advance for sharing your thoughts and experiences.
 
Very common symptom of low refrigerant.
Cheap fix it just to get DIY R134 recharge kit. Get the one with additional leak sealer and most of the time it would be good to fix this problem.
 
though this is not the cause for reMarkable's a/c problem, his was a bad thermostat....

I would not suggest using Freon with the sealer additive. Have heard from many mechanics that it can cause some expensive problems. It's a poor man's way of fixing things, like the radiator sealers...it just clogs up things that shouldn't be clogged up. The best thing to do if you have a leak is to replace the bad parts.
 
rkhanso said:
though this is not the cause for reMarkable's a/c problem, his was a bad thermostat....

I would not suggest using Freon with the sealer additive. Have heard from many mechanics that it can cause some expensive problems. It's a poor man's way of fixing things, like the radiator sealers...it just clogs up things that shouldn't be clogged up. The best thing to do if you have a leak is to replace the bad parts.
Click to expand...

I've been told the same by trusted mechanics. I would use it as a last resort on vehicle that is no longer receiving thorough maintenance (i.e., last legs).
 
Sounds like it was already diagnosed / fixed (bad thermostat). If it wasn't diagnosed, here are some things to check (per Motor Week):

1. Cabin filter, replace if dirty or if you haven't replaced it in a while
2. Radiator / condensor coils - if it looks dirty, clean with a garden hose and engine cleaner
3. Make sure the cooling fan is spinning - if it isn't, it may be the relay
4. Look at the AC belt and make sure the center part is spinning when the belt is spinning.
 
Ok, all you knowledgable A/C guys, I've got a slightly different A/C problem that diagnosis assistance would be greatly appreciated.

Background: '06 with just under 60k. Just replaced tranny fluid and engine oil right before 1500mi vacation last week (shouldn't be relevant, but try to document everything just in case).
During vacation, A/C starts acting erratic. Unlike reMarkable, my engine temp thermostat is staying pegged mid-range, but 20 minutes into the drive, the A/C goes from cold to VERY WARM. In one instance (after sitting idling in a drive-through line for a few minutes) when we got out on the highway, the air out of the vents was 15 degrees WARMER than the outside air - per rough hand out the window check. This was during 75+MPH drive through TN and KY hills/mountains, so thought maybe it was because I was working the vehicle pretty hard.
Several times I was able to 'reset' the A/C by turning off and back on, then it got cold. Today, that trick didn't work either on a 25 minute trip around town today for errands - in relatively flat Wisconsin.
As I've mentioned before my 3yo gets car-sick very easily, and a not-cool car makes this much more likely, so I'll be trying Heat's list tonight. Any other thoughts as well, such as clogged drain line for condensation? Any other things I should be checking while I'm in there?
 
reMarkable - I'm glad you got it fixed as a failing thermostat could have caused a much worse problem. It seems now that an intermittent a/c should be a clue to watching the temp gauge, which leads to my next question...

How often do you check your coolant level and was it low?

othercarsasaab - How is the operation of the a/c compressor? If you don't know how to use refrigerant gauges, I would take it to somebody who does.
 
Just found this thread, and have a problem that is similar but different. :)

We were on the road in our 2006 Mazda 5 for a couple hours in this recent heatwave, when we noticed that the A/C was becoming markedly less effective. The air that was coming out of the vents was still cold, but the fan seemed to moving very little air. The Auto climate control was responding as it should (the display would show the fan at full power when we turned the desired temperature down), so I don't think it is a sensor issue. And because the air was still cold I don't think that we've lost any refrigerant. The engine temp remained steady at a moderate level. After stopping for a while the A/C returned to normal function, and still works fine for short trips. The behaviour has reappeared a couple times since, but only after driving a long distance in high ambient temperatures.

I know that running the A/C adds to engine temp, but I don't know if there is a safety feature that reduces the A/C power to protect the engine. Has anyone else observed this kind of behaviour, and is it possibly a normal function?
 
I think the problem is your evaporator icing up blocking air flow because this only happens after running the AC for a long time on a hot and humid day. Also, as you have mentioned, the AC will return back to normal after you have turned the AC off. With the AC off the ice will melt from the evaporator and it will start to work normally again. To test this theory, when it happens the next time while you are driving, just turn the AC off for a few minutes and then back on and to see if this will fix the problem.
 
We just started having the exact same problem as CrashCDA. Coming back from Colorado,the air had been on for hours. We were in Illinois when I felt the temperature in the vehicle rise. I dismissed it as we were driving directly into the sun. About 20 miles from our next gas stop,we notice the air was cold coming out of the vents,but no matter what fan speed it didn't pick up. We shut it off for the rest of the return trip since we were only about 60 miles from home. Wife drove car into town the next day and air worked as normal. WTH?
 
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I am chiming in a little late on the subject, but it seems as though the various issues could be related to needing a recharge. Each vehicle mentioned is at least three years old. With regular usage, this is about the life expectancy of many newer vehicles. The new systems hold very little refrigerant. The old r12 systems would work for a decade or more.

I would recommend that these systems be recharged by a shop that has the correc equipment. I've used the cans in the past, but with these newer vehicles, without a gauge, you can overcharge the system. If that happens, the air will blow warm. The machines can be inputed with the exact amount the vehicle needs as stated on the sticker under the hood.

Good luck to you guys.
 
I have ahd a similar problem as the original poster. I have a 2002 Pro5 with 66,000 miles and this summer the AC became markedly less efficient, to the point that it would be cold for 5 minutes and then no cool air at all. The fan is blowing hard. I took it to my local guy, who did an evac/recharge. When they did the recharge, they used a dye and told me to come back in a few days so they could check it out. On my way home the AC seemed to be working, but it was 100 degrees in the car when i got in it and started to cool down just as i was getting back home.

He said that the AC system is CLOSED, so loss in refrigerant is due to a leak. Is that true? Your help is appreciated!!
 
dont mean to hijack the post but I a had similar problems as the first person but I know I had something to do with it as problem came after I tried to recharge the system - just posted a new thread on it.
 
Interesting. We picked up an 08 Mazda5 last spring. Once in a while I've notice intermittent issues with the A/C not performing adequately. Sometimes it does not blow real cold and seems to struggle to cool the car down during a 30 minute commute. When I've noticed it, it is usually really hot, 90+. But, the ambient temp display on the dash is wrong, and s-l-o-w-l-y changes.

Specifically, it can be 100 out. But the dash ambient temperature reports 78. During my 30 minute commute, the dash ambient temp will slowly raise to about 95 by the time I get home but not get to the actual outside temperature. The car's ambient temperature display frequently exhibits this symptom, maybe 1 out of 8 to 10 times of driving.

I may buy another ambient temp sensor and see if that is the problem--I hope so. Otherwise, there maybe a logic problem in some controller version, or a controller / computer going bad.
 
Thanks user "reMarkable"! I have similar problems with my 2008 Mazda5. Since my car only has 50,000 miles, I am taking it to the dealership to see if they will replace the thermostat for free under the powertrain warranty.

Update: After an argument with the acting manager and telling them how to diagnose the car, the Mazda dealership replaced the thermostat without charging me.
 
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Same problem. How did you resolve it?

reMarkable said:
I have a Mz5 2008 with approx. 75,000 miles on it. The A/C has always worked very well. Suddenly today at 88 degree F it got erratic. It stopped blowing cold air (just ambient temp air instead) most of the time. As soon as we were convinced the A/C was absolutely dead - then it would give us a cold blast for a 30 seconds to a minute - before it would kick out for another 5 minutes or so. We experienced this with the recirc on and off - and both at highway and city speeds. Anyone have this in their Mz5 before?

I hate to bring it to the dealer for the difficulty getting it there and the obscene pricing. I also can bring it to my local garage around the corner from work, where they are honest and I'm a regular for maintenance. Other facts: I subscribe to alldatadiy.com for my Mz5 and I have checked through the TSBs and whatnot there - haven't seen anything that sticks out. One other fact - I have an extended repair warranty through my insurance with a $250 deductible.

Any thoughts on what it might be and how best to proceed? Thanks in advance.
Click to expand...
 
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