Heater blowing cold air in front but back is fine (2017 CX-9)

Yes, very unfortunate (but not at all surprising) that Mazda is not going to offer any goodwill help with this issue. Have you decided yet what you're going do? I believe the dealer's 5-6K CAD estimate is just for a new head installed, with a new engine being more like 8-10K CAD.

The one thing I do recommend staying away from is a replacement engine from a wreck, because of the much higher than normal probability of the replacement engine having the exact same problem that happened to your engine.
 
Service manager priced out the repair, which is replace the cylinder head. Said on paper it would be $6,300 plus tax but then got it down to $5,250. 1 year parts and labour warranty. He said the cylinder head part has been updated since my 2017 so hopefully that means less of a chance of it happening again. Actually they're on the third different part number now for this generation (2016-).
 
I am defitely thinking of making this more visible in Ontario. My lawyer cousin said to google any lawyers in Ontario regarding this issue to see if any are advertising looking for clients. I did not find anything. But he said if you try to initiate it, be careful about being the lead plaintiff - you could be on the hook financially if you lose (in Canada, we have a loser pays litigation system - if you sue someone and lose you will on the hook for a portion of their legal costs. Same in reverse).

Probably could email some auto news sites as well now that you mention it.
 
So... I got the car back March 10th. Service Manager is very professional but the mechanics keep doing what so many do. Left greasy handprints all over the tan coloured A pillar. Undertray was hanging down 1 cm and the bolt clearly was not tightened up. Unplugged the dashcam from the camera, which is behind my mirror so I didn't notice until a couple minutes later. They did this last time and in the feedback survey I mentioned I'd appreciate it if they unplugged it from the 12V instead and left the power cord lying near the shifter so it's obvious it needs to be plugged back in. And it had multiple dings on the door. It was at the dealer for five weeks. The lot is huge. They could have parked it in the back but I'm pretty sure they always had it parked around other cars. All these things were taken care of over the next few days.

However, two weeks after I got it back, I started the car in the morning, used heat for 5 minutes and then turned it off as it was no longer needed. Yet it would still blow heat where I could feel it with my hand about 15 inches away. It was blowing like as if there was one setting below the minimum fan level. Two weeks after that it happened again. Both those times, this stopped later in the day.

Yesterday, drove it at 4pm for 10 minutes with windows opened as it was about 30 C/90 F and sunny outside. But then my wife drove it and she needs AC. It was blowing hot air for the 10 minute drive back despite being on AC. This morning I start it up and then tried AC and it was working fine. But dealer said to bring it in after I told them the above mentioned. Service manager said a small leak in the condenser. They did the test and the freon is very low. He said that could be a $1,000 CAD job. But in the meantime he's putting some JB Weld on it and then they'll test it again after that sets.

And as many of you surely have noticed, there are rock chips where the roof meets the windshield. I posted about this last November. I dremeled those spots to the bare metal and then put the paint pen on. There's also a nickel sized rust spot in the middle of the roof. I did the same thing but somehow it kept rusting. So I did it again. And once again, it has rusted again. As I walk through the dealership I look at so many CX9s, CX5s, CX3s and CX30s. So many of them have the chips in the same spot. I mentioned that to the service manager weeks ago and he showed me his newer model CX9 today and he got a couple now. He said he was driving behind a dump truck and heard the pebbles bouncing off his car.

He said if there's enough people complaining about this then he hopes Mazda will take of it for people. He said he feels like the paint is too soft.
 
Hello Brother.
I am a 2017 CX-9 owner, and I experienced exactly the same symptoms as you today and found your post. There's been a long thread about this problem but I'm curious how you finally solved this.

It seems to be a front blend door actuator issue, but I get cold air coming out of both fronts and the rear is fine. The fact that hot air is coming out of the rear dismisses the possibility that it is a heater core or other problem. Is there only one blend door actuator at the front or on both sides? Anyway, I would appreciate it if you could share how you solved this.
Ultimately, it was the cracked cylinder head on my engine. They replaced that, which is a big job. As far as I know the actuators were working all along.
 
Ultimately, it was the cracked cylinder head on my engine. They replaced that, which is a big job. As far as I know the actuators were working all along.
Oh....
Ultimately, it was the cracked cylinder head on my engine. They replaced that, which is a big job. As far as I know the actuators were working all along.
I checked the actuator this morning and it seemed fine. But it's leaking coolant just like you.

I really hope not, but...

Interesting. How could a leak from a cracked cylinder head be related to the front heater?

Were there any problems with the heater core? I am so devastated right now.
 
They made no mention of touching the heater core. I also didn't understand how a coolant leak caused the heating issue.

As for diangosing it, I know they inspected it closely. I'm not sure what else they would have done. I myself couldn't find the crack just by standing in my driveway and looking with a flash light.

You say you bought it used. Private or a dealer? Is there some kind of warranty considering it's been not even three months? How much mileage on it?
 
It seems to be a front blend door actuator issue, but I get cold air coming out of both fronts and the rear is fine. The fact that hot air is coming out of the rear dismisses the possibility that it is a heater core or other problem. Is there only one blend door actuator at the front or on both sides? Anyway, I would appreciate it if you could share how you solved this.
There are separate front and rear heater cores. The front one might be plugged. I'd try a strong cooling system cleanser to see if the deposits plugging the core can be cleaned out. The final option is to take the dash apart and put in a new front heater core. CHANGE THE COOLANT MORE OFTEN THAN MAZDA ORIGINALLY RECOMMENDED.
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There are separate front and rear heater cores. The front one might be plugged. I'd try a strong cooling system cleanser to see if the deposits plugging the core can be cleaned out. The final option is to take the dash apart and put in a new front heater core. CHANGE THE COOLANT MORE OFTEN THAN MAZDA ORIGINALLY RECOMMENDED.
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wow! Thank you very much for your answer with professional knowledge.

The front heater did not work well, and looking at the symptoms of a coolant leak, it seems certain that there is a leak somewhere in the pipe connected to the front heater core.

Thank you again for answer.
 
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I did indeed mention the possibility of a cracked cylinder head in advance because I did a lot reading online after I noticed a coolant leak on my driveway. But at first I didn't realize there was a leak because I rust proofed both my cars shortly before my problems started. So that grease was dripping already onto the driveway.

I kept a detailed journal of the issues and what happened each day for a few days with the heat before I noticed the coolant leak. Then at the end of the journal I wrote that I noticed a coolant leak and wrote down the possbilities based on my research. It was for myself and the mechanic. I presented it to the dealer the same time they were doing the diagnostic to figure out what the problem was. They confirmed cracked cylinder head.

I kept the journal for myself in case it might help me in the future if there's a class action lawsuit perhaps. Not sure it will be useful but keeping just in case.

Let's hope it's not as serious as you fear it to be.
 
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