Heater Core

I just did a pretty extensive search on this and, as you know, there is VERY LITTLE info available on this repair. I get the distinct impression is not a DIY job. Good luck on this!
 
Called a couple dealerships and downloaded a bunch of manuals. Looks like I should be able to piece together the info. I found dash removal steps and it references other removals which I was able to find. Also got some info from the dealership. Once I get all the parts I'm going to dive in head first.
 
paris1 said:
I think if I lived where you do I might consider going without heater!(sun)
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I would, but I have to SMOG the vehicle and the bad core is causing a P011A error code. I'm sure I could bypass the sensors somehow, but I do regularly drive to work at 5am and it would be nice to get a little heat.
 
They say cars are built around heater cores. Meaning that to get there you have to take half of the car apart.
Is it clogged? Did you try to blow it or flush with garden hose?
 
It's been flushed, both sensors that trigger the CEL have been replaced, the thermostat has been replaced and I bit the bullet and had a dealership diagnose the CEL. It's a bad heater core. Only 70k miles, it actually started acting up at the tail end of last winter. I called and emailed Mazda to see if there was any way they would help with the repair but they "respectfully declined." Unfortunately this problem isn't all that uncommon.
 
This is looking more and more like a weak point on CX-5s (maybe early models-hard to tell) as I'm seeing it pop up more and more on various internet venues. Most seem to be 2013-14 at this point.
 
FSM definitely doesn't make heater core an easy part to service. Really unclear...at least with docs I have one would be somewhat on their own.
 
I have found all the steps in shop manuals, there about 30 individual components that have their own sub instructions.

I bought mine in 2012, it was one of the first shipments the dealership got. I think it's the same part through 2016.
 
Curious to see what your heater core FSM docs show... my '15 docs are abysmal and not worth posting

Screen%20Shot%202019-01-08%20at%206.47.32%20PM.jpg
 
Quite a chore, eh? Pretty much everything must go. All the trim, levers, steering wheel and A/C... What a pain. I wish you best of luck.
Nowhere it is specified what causes the blockage. Wonder if it has to do with this specific coolant, or assembly debris, or ?..

By the way, to pass SMOG, disconnect both hoses from heater core and plug them together under the hood, with a piece of pipe or a couple of fittings and some hose, that should take care of the check engine light. If the core is a problem.

As for having the heat... I thought I read in another thread that you saw water going through the heater core when you and the dealer flushed it. If so, try driving around with the core disconnected for a while. Whatever clogs this thing may just dry up and you'll be able to blow it out with compressed air? Then connect the hoses and see what happens.
 
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Kedis82ZE8 said:
Curious to see what your heater core FSM docs show... my '15 docs are abysmal and not worth posting

Screen%20Shot%202019-01-08%20at%206.47.32%20PM.jpg
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You actually use the AC unit removal instructions. The heater core and evaporator are colocated. Which means the refrigerant also has to be evacuated and recharged.
 
yugrus said:
Quite a chore, eh? Pretty much everything must go. All the trim, levers, steering wheel and A/C... What a pain. I wish you best of luck.
Nowhere it is specified what causes the blockage. Wonder if it has to do with this specific coolant, or assembly debris, or ?..

By the way, to pass SMOG, disconnect both hoses from heater core and plug them together under the hood, with a piece of pipe or a couple of fittings and some hose, that should take care of the check engine light. If the core is a problem.

As for having the heat... I thought I read in another thread that you saw water going through the heater core when you and the dealer flushed it. If so, try driving around with the core disconnected for a while. Whatever clogs this thing may just dry up and you'll be able to blow it out with compressed air? Then connect the hoses and see what happens.
Click to expand...
I wasn't present for the flush, not sure what came out. The dealer said they have had other cars with the same issue and the flush has only been a temporary fix.
 
Hiflyer731 said:
I wasn't present for the flush, not sure what came out. The dealer said they have had other cars with the same issue and the flush has only been a temporary fix.
Click to expand...
They want the job, don't they... And flush means everything is wet inside the core. If it's sort of molasses that plugs it, it may or may not dry up to be blown out with air. Dealer didn't try to blow it out, because if plugged solid and full pressure of the shop air is applied, this may rupture the core.
I mean, I'd pass the smog test and let it dry for a while. Then use pancake compressor to blow it, without sealing the inlet.
 
Order has been placed. $410.77 shipped for all parts plus one gallon of coolant. The dealership quoted $454 for just the core. Only additional cost should be a flush kit and refrigerant recharge. Mazdas techs have told me it's about 7 hours if you know what you're doing. I have another vehicle i can drive so i don't need to do this quick. I imagine it will take at least double the time. Likely will start after the MLK holiday. I will post the parts list and steps when i'm done in case something was omitted.
 
It's done. Did it solo over the last two days. Took 7 hours to get to the core and 5 hours to put it all back together. Relatively straight forward, just time consuming. Still have to drain and refill the cooling system after the flush and get the AC recharged. The old core seemed about 70% blocked just based on me trying to blow through it.
 
Wonder what is the core blocked with. Sediment from the coolant?
Look into the vacuum coolant system refill. Relatively inexpensive device, works every time with no air lock. Many shops have that too. Reduces time and headache.
 
Hiflyer731 said:
It's done. Did it solo over the last two days. Took 7 hours to get to the core and 5 hours to put it all back together. Relatively straight forward, just time consuming. Still have to drain and refill the cooling system after the flush and get the AC recharged. The old core seemed about 70% blocked just based on me trying to blow through it.
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Although Ive been trying to DIY on my vehicles all the time for many years, but I dont know if I have the courage like you to replace the heater core in my CX-5! Thumbs up to you! (cool)
 
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