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Discussion Starter · #1 ·
Hi, I'm trying to troubleshoot and fix my the air conditioner in my son's 2004 6s. It has the auto air conditioner system. Some days it will blow cold air from the vents (approx 45f) but most time is closer to ambient exterior temps.

Most times it is not cool. Works about the same when on auto or manual. I've taken pressure of the A/C system and it looked good on a 90 degree day was 250/32 and checking temp of condenser was around 170f. I don't remember the radiator temps but car gauge was in the normal range. Fans all working but not sure if they run at full power or not. It has never overheated so I'm assuming they are fine.

I haven't found hardly any information about this system, or how to further troubleshoot. Any information or service docs would be much appreciated.
 

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You might want to check if the vent is stuck opened. Have you done any electrical repairs? The fan's connection might be interchanged.
 

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Discussion Starter · #3 ·
I'm not sure of what you mean by vents being open. I'm trying on fresh air and recirculating.

If your saying one of the blend doors may be getting stuck, I agree. I just don't know how to troubleshoot a blend door problem in this car.
 

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Discussion Starter · #5 ·
That would be the best possible situation, but given the compressor is running and not cycling plus the pressures I don't think it is low. It could be but I'd hate to add more without looking at all possibilities.

One of the only videos I found about A/C on Mazda6s was where they removed the whole dash to replace a sensor on the evaporator but they didn't explain what the sensor was or the symptoms the A/C was having.
 

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Fine then, figure it out on your own. No offense, but i hate when new owners ask older owners how to fix something and then poopoo the suggestion. But like its been mention, we are volunteer owners and dont really appreciate our time being wasted "helping".
 

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My 06 would need a recharge about once a year or less. I just used one of those DIY bottles. The system only takes like .6 lbs and doesnt take much to go low.
I was about to suggest that but he said he checked the pressure. I don't know what is the recommended value so I didn't.
 

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I'm not sure of what you mean by vents being open. I'm trying on fresh air and recirculating.

If your saying one of the blend doors may be getting stuck, I agree. I just don't know how to troubleshoot a blend door problem in this car.
Yes, that's it. I don't know where exactly that is on a Mazda but it should be near the evaporator.

It is possible that the evaporator is also dirty, but you mentioned that there are times that it is blowing cold air.

Try adding refrigerant and see if there's improvement. Just make sure you don't go beyond the upper limit of the recommended value.
 

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Discussion Starter · #9 ·
TalonTSI90 not sure what I said to offend you, I thanked you for your suggestion. However I don't think anything in my symptoms points to low refrigerant. While I am new to the Mazda6s air conditioning system but not new to automotive a/c systems. I've fixed probably a dozen systems over the years. Overfilling a system can be worse for a system than being underfilled. Therefore I'd like to explore all possibilities before adding more.
 

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Discussion Starter · #10 ·
So an update, I remembered someone talking about checking the temperature of the hoses before and after the evaporater. Normal would be hot on the high side and cold on the suction line after the evaporator. So I touched both lines and to my surprise the high side and low side lines were both cool. Touching the pressure line between the compressor and condenser was very hot. So I'm suspecting blockage in the condenser.
 

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So an update, I remembered someone talking about checking the temperature of the hoses before and after the evaporater. Normal would be hot on the high side and cold on the suction line after the evaporator. So I touched both lines and to my surprise the high side and low side lines were both cool. Touching the pressure line between the compressor and condenser was very hot. So I'm suspecting blockage in the condenser.
I agree, adding coolant when it is not needed can be a bad idea.
I am assuming that you ave this table but it looks like your high pressure is at the bottom of the lower limit for your ambient.
243305


Maybe it is causing the refrigerant pressure switch to open and close relative to the changes in ambient and relative coolant pressure variation?
 

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Looking at some old pics, the high pressure port in this vehicle is located between the compressor and the condenser. Someone please correct me if I am wrong.
So, if the condenser was blocked, you would be seeing an extremely high pressure (>300), unless the system was low on gas.
Where is the pressure switch located?
 

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Discussion Starter · #14 ·
Looking at some old pics, the high pressure port in this vehicle is located between the compressor and the condenser. Someone please correct me if I am wrong.
So, if the condenser was blocked, you would be seeing an extremely high pressure (>300), unless the system was low on gas.
Where is the pressure switch located?
Yes it's located prior to the condenser. It's not completely blocked since I'm seeing pressures on the suction tube as well. Could verywell be low on gas but won't matter as it needs evacuated to clear the clog. I was asking advice on a mobile A/C forum and they agreed it's likely clogged, actually said sounds like the screen is clogged. The screen is located in the accumulator which is attached to the condenser. They told me to clean the screen and replace bag of desiccant, looking at parts diagram I didn't even see where there was a desiccant bag. After seeing some closer pictures of the condensor the accumulator/dryer is attached and the desiccant bag is replaceable and really cheap. I thought it must have been sealed and I would have to replace the entire condensor. They also said there was someone there asking about the same car a week ago with same issues. I plan on replacing the expansion valve while it's open.

Replacing the desiccant bag or condensor is not a quick procedure though, the front bumper cover, under tray, headlights, actual bumper and core support have to be removed to get to it. Here's a video going through the whole process: Youtube replacing Mazda6 condenser

Also I had been worried about the auto air controls and blend doors etc and not knowing how to troubleshoot. I found a link on this forum to another forum that had a link to a scan of the 2004 Mazda6 service manual. Section 07-02 has all the steps to put the climate control into debug mode - very detailed. You can put it in debug mode and it will spit out codes for any issues by flashing the rear defroster light with long and short blinks, then there is a table with codes.
 

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Discussion Starter · #15 ·
It's also interesting that the service manual makes no mention of the desiccant bag or how to replace. Maybe they assume it's obvious - wasn't to me. All the other systems I have worked on have had a separate dryer/accumulator which was placed near the firewall and easy to see.
 

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Well, hopefully that solves the issue. Take lots of pics and share for others to follow.
 

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I was plagued with problems with my 6 regarding cold ac, must have been a slow leak at a seal or something because a refill would show low to no pressure and once pressure was back up from a recharge it worked great. This desiccant bag is new info to me shrug
 

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Discussion Starter · #18 ·
Jman1200 - will do!

Dr Boom - leaks can be frustrating to find. I'd recommend a UV kit with a decent light, one that's flashlight sized not the little pen light. Mine also came with a dye injector and dye. The injector is like a syringe that connects to the low side service port. Read the instructions - I think system should be off so you don't damage the compressor. I also have an electronic leak detector and it works well but you need to get the tip right next to the components which can be difficult. I ended up with the UV detector when I couldn't find a leak with the electronic one. It ended up being the evaporator. With UV I saw the drain pipe glowing. Electronic one picked it up if I put it in a vent or up the drain hose but hadn't thought of that before hand. I also use nylog on the o-rings - was recommended to me by an a/c guy years ago it's a sticky mess but works.
 

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Discussion Starter · #19 ·
Something like a Master cool 53351-b UV leak kit for $54 at Amazon.
 
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