CX-5 heater core issues discussed on another Mazda forum

[Mazdiod2]

If the heater core is replaced per the Mazda manual the AC system has to be opened and then recharged, so maybe the GEICO repair wasn't really done right? Maybe they didn't flush and refill 2x with Mazda coolant either.
I know if I were to try and replace the heater core I would want to use the Youtube method. I guess the problem might be procuring the proper core. I guess the Mazda part is expensive, but it might be worth it to buy the Mazda HVAC unit just to remove and use the core.

 

[dunhillmc]

On my receipt at 92,500 miles they wrote: "Technician was able to verify customer concern and found the heater core to be restricted. Recommended to replace. Technician replaced heater core per insurance authorization. Cleared codes. Checked repair, road tested, and verified all to be okay at this time." Invoice shows they installed a heater core for $501.22 and 2 things of Mazda Cool(ant) at $54.08 each. Why it is failing again at 122,000+ miles doesn't make any sense.

I saw an inspection video which they say shows the broken strut mounts.

I have an appointment tomorrow afternoon at an independent mechanic.

Most dealers would correct that at no charge for a warranty repair. I'd call them and say that what they fixed was broken again

 

[Lharri1467@]

Most dealers would correct that at no charge for a warranty repair. I'd call them and say that what they fixed was broken again

I had my car inspected at a mechanic today. The didn't find anything mechanically wrong with the car to fail it on inspection. However, it failed the emissions portion due to the check engine light. They cleared the light. However, it came back on tonight on the 3rd drive cycle. The mechanic thinks it's a bad thermostat and ECT sensor. It will cost about $450 to fix. However, if it's the heater core I'm going to be upset if I replace the other parts and it doesn't fix the issue. I think I will provide them with TSB 07-007/17 that was posted here. Interestingly, they didn't mention needing to replace the serpentine belt or the rear shock mounts. As far as the heater core, I noticed tonight that the defroster didn't seem to be working properly. The side windows were still really foggy even with the defroster running. Do you think this is a thermostat, ECT sensor or heater core issue?

 

[Kedis82ZE8]

Thermostats are so cheap ($27.06) though that almost not worth the trouble of testing it other than to confirm it was bad or or not.

2012-2018 Mazda Thermostat PE01-15-171 | OEM Vehicle Parts

Thermostat - pe0115171. Genuine Mazda® Parts & Accessories. Manufacturer Warranty. From the Dealership to your Door.

www.oemvehicleparts.com

That reminds me I about replacing the thermostat when I do the hoses in the next two years.

 

[Jmaz]

About 2 weeks ago I replaced the thermostat when replacing the upper and lower radiator hoses. No problems just preventive maintenance. All Mazda parts. For those who aren't aware, never, ever , install one of those cheap, off- the rack, blister pack special, thermostats (IIRC that Stant brand is one) from the auto chain stores. Something as critical as protecting the engine from overheat demands a quality OEM (not "OEM" brand -- more confusing marketing) part.
It takes removing more parts than desirable just to get to the thermostat and there are videos on youtube showing how to do it. It'd be good to view one or two. Here's a few things to know.

1) it's possible to do without removing the battery and battery tray.
2) the rubber support ring, which also acts as the thermostat cover gasket has a protruding tab (goes at 12 o'clock position) that fits in a depression on the engine and cover. This puts the little "jiggler" vent hole at the 12 o'clock position also. Get this correct or there will be a leak. No sealant required for this job.
3) the plastic thermostat cover has metal inserts molded in the bolt holes. These bottom out and prevent cracking the plastic when tightening. Hard to get a torque wrench in there anyway so an appropriate snugging with my 1/4" ratchet was sufficient.
4) a cheap pair (~$6 each@ Walmart or ~$10 set of 2 @HF) of 11" curved needlenose pliers made accessing the hose clamps much easier.

 

[yrwei52]

Thermostats are so cheap ($27.06) though that almost not worth the trouble of testing it other than to confirm it was bad or or not.

2012-2018 Mazda Thermostat PE01-15-171 | OEM Vehicle Parts

Thermostat - pe0115171. Genuine Mazda® Parts & Accessories. Manufacturer Warranty. From the Dealership to your Door.

www.oemvehicleparts.com

View attachment 329308View attachment 329309


That reminds me I about replacing the thermostat when I do the hoses in the next two years.


View attachment 329312View attachment 329313

View attachment 329316

$27.06 for a simple thermostats is cheap? I still remember I paid $5 in early days for an AC-Delco GM OEM thermostats which I though it’s pretty expensive!

Actually we’re lucky CX-5 owners with the 2.5L NA w/o cylinder deactivation. If you have a 2.5L NA with CD, we’re going to talk about $454.36 MSRP coolant control valve, PYFD-15-16ZA, not $27.06 thermostats!

New to the community...Thermostat issue (2020 CX-5 with code PO126)

Hello all, New the community.......
Simple question- I am stumped--- have a 2020 Mazda CX-5 with code PO126-- thermostat--- dealer wanted 1500 to fix this?! I am unsure of the location of the thermostat--- there seems to be security type star bit screws around where I believe it to be but dont want to start wrenching until I am sure of the location- it is an AWD 2.5 gas engine. Sorry for the seemingly simple question, but the vehicle isnt mine and I dont want to do something harmful to their car...... You Tube usually is spot on, but not so much in this instance on a 2020?!?!

So this’s another potential problem for 2.5L NA with CD which is very expensive to fix:

TSB No.: 01-005/23 Check Engine Light On with DTC P0126:00

And additional gasket、washer、o-ring、connector are needed to replace coolant control valve:

 

[Mazdiod2]

I got my FL22 yesterday so I'm trying to decide how I want to drain as much coolant as possible before I refill. I have looked at how to replace the water pump and I'm wondering if that would be a good place to drain coolant, plus from the radiator/bottom hose.

 

[Jmaz]

I got my FL22 yesterday so I'm trying to decide how I want to drain as much coolant as possible before I refill. I have looked at how to replace the water pump and I'm wondering if that would be a good place to drain coolant, plus from the radiator/bottom hose.

The 2 times I replaced coolant by doing 2X drain and fill (once at ~44k miles/6 year mark and once 2 weeks ago) I just opened the little plastic cover underneath the car below the radiator and opened the plastic drain petcock to drain the coolant. Only open enough to get a full stream otherwise it may pop out and create a gusher. No need to pull hoses and there is no drain plug in the engine block. Draining should get almost/or exactly 1 gallon. I drained 1 gallon and added same then drove around to mix with old coolant and then drained another gallon and refilled with fresh. The second time I just ran the engine at 2500 RPM for 5 minutes after it was at operating temperature so the engine was good and hot . Didn't even have to drive around. I used exactly 2 gallons the times I did it. Easy job.

 

[yrwei52]

The 2 times I replaced coolant by doing 2X drain and fill (once at ~44k miles/6 year mark and once 2 weeks ago) I just opened the little plastic cover underneath the car below the radiator and opened the plastic drain petcock to drain the coolant. Only open enough to get a full stream otherwise it may pop out and create a gusher. No need to pull hoses and there is no drain plug in the engine block. Draining should get almost/or exactly 1 gallon. I drained 1 gallon and added same then drove around to mix with old coolant and then drained another gallon and refilled with fresh. The second time I just ran the engine at 2500 RPM for 5 minutes after it was at operating temperature so the engine was good and hot . Didn't even have to drive around. I used exactly 2 gallons the times I did it. Easy job.

Great info! Just want to be sure, you have a 2014 CX-5 with 2.5L NA, right?

It’s unfortunate that we can no longer get OEM FL-22 concentrate but only 55/45 pre-mixed FL-22 coolant. It’d be cheaper to have the FL-22 concentrate and do coolant drain&fill or flush with distilled water and pour in concentrate the last to the Full mark as most of time the distilled water stayed in cooling system after the drain would be about a half of the total capacity of the cooling system.

Now we just have to waste a gallon of fresh pre-mixed FL-22 coolant doing 2x drain&fills making sure we can get rid of as much old coolant as possible which can’t be drained out completely.

 

[Jmaz]

Great info! Just want to be sure, you have a 2014 CX-5 with 2.5L NA, right?

It’s unfortunate that we can no longer get OEM FL-22 concentrate but only 55/45 pre-mixed FL-22 coolant. It’d be cheaper to have the FL-22 concentrate and do coolant drain&fill or flush with distilled water and pour in concentrate the last to the Full mark as most of time the distilled water stayed in cooling system after the drain would be about a half of the total capacity of the cooling system.

Now we just have to waste a gallon of fresh pre-mixed FL-22 coolant doing 2x drain&fills making sure we can get rid of as much old coolant as possible which can’t be drained out completely.

Yep, still have the 2014 CX-5 NA Touring. I just used Zerex Asian green. The factory fill was changed out at 6 years. The second was 2 weeks ago (4 years later). So that's twice in 10 years. I'll keep to a 4 or 5 year changeout. The coolant drained looked great and was clear each time. Hoses (and belts) and thermostat shouldn't need done anymore. Probably not spark plugs either since those were just done also at 71k miles.
I don't like wasting premix coolant either on these drain and fills but dislike even more wasting expensive FZ transmission fluid on a 2X or 3X D&F. Luckily these D&F's are done every so many years. For me anyway, I only drive about 7k miles/yr. Not like oil changes.

 

[Kedis82ZE8]

$27.06 for a simple thermostats is cheap? I still remember I paid $5 in early days for an AC-Delco GM OEM thermostats which I though it’s pretty expensive!

Extremely Off Topic…. I apologize

I was just commenting to the wife today when I could get 5 dozen oysters in the shell for $28 in the ‘90s… not $72 as it is today

I goto the source oyster field store which serves basically serves the entire Puget Sound (WA state) oyster supply

I like to just grill them on the BBQ…that is dinner tonight

They were harvested from the bay yesterday so very fresh

Samish Oyster Bar and Shellfish Market | Taylor Shellfish Farms, Seattle WA

CHUCKANUT ROUTE UPDATE: road is open FRIENds! Officially on Summer Hours! Retail & Kitchen open 11am-7pm JULY 4th HOURS: Open 11-4pm! This location has a limited seasonal menu that updates daily, so there is no online menu available. Parking is limited so please be patient, drive carefully...

www.taylorshellfishfarms.com

Mike Rowe did a dirty job episode at the place back in 2006

"Dirty Jobs" Alpaca Shearer (TV Episode 2006) ⭐ 7.1 | Reality-TV

44m | TV-14

www.imdb.com

 

[Kedis82ZE8]

TSB revision released about a week ago

https://static.nhtsa.gov/odi/tsbs/2024/MC-11003350-0001.pdf

 

[yrwei52]

TSB revision released about a week ago

https://static.nhtsa.gov/odi/tsbs/2024/MC-11003350-0001.pdf

View attachment 329661

So this “thermostat stuck open” in this very expensive Coolant Control Valve saga on 2.5L NA with cylinder deactivation continuous ⋯

 

[Mazdiod2]

I have to figure out what to do with two gallons of fairly clean (but too weak) coolant because I don't think you're supposed to dump it.

 

[HyFlyer]

I have to figure out what to do with two gallons of fairly clean (but too weak) coolant because I don't think you're supposed to dump it.

[Edit to correct... thanks @Kedis82ZE8 ] municipal wastewater system water treatment plant is not the place.

The question has caused me to look up info for my county which is to turn in at our county vehicle maintenance garage or check with local commercial repair facilities. (For all automotive fluids) .

 

[Kedis82ZE8]

In Pueblo County, Colorado, you can recycle coolant by utilizing the services provided by Pueblo RecycleWorks and the Pueblo Department of Public Health & Environment. They offer a Household Hazardous Waste (HHW) program, which includes the proper disposal of automotive fluids like coolant.

Here are the steps to recycle coolant in Pueblo County:

1. **Pueblo RecycleWorks**: This facility accepts various types of recyclable materials, including hazardous household waste. They are located at 1595 Stockyard Rd, Pueblo, CO 81001, and are open Thursday to Sunday. For more details on what they accept and their hours, you can visit their official page at [Pueblo RecycleWorks](https://www.pueblo.us/1668/Recycling).

2. **Household Hazardous Waste Collection**: The Pueblo Department of Public Health & Environment also handles hazardous waste. For information on specific disposal guidelines and to ensure that coolant is accepted, you can contact them directly or visit their website at [Pueblo County Household Hazardous Waste](https://county.pueblo.org/environment/household-hazardous-waste).

For more information on recycling and disposal services in Pueblo, you can check the [Pueblo RecycleWorks Information](https://www.pueblo.us/1668/Recycling) and the [Pueblo County Recycling](https://county.pueblo.org/environment/recycling) pages.

 

[Lharri1467@]

I had my car inspected at a mechanic today. The didn't find anything mechanically wrong with the car to fail it on inspection. However, it failed the emissions portion due to the check engine light. They cleared the light. However, it came back on tonight on the 3rd drive cycle. The mechanic thinks it's a bad thermostat and ECT sensor. It will cost about $450 to fix. However, if it's the heater core I'm going to be upset if I replace the other parts and it doesn't fix the issue. I think I will provide them with TSB 07-007/17 that was posted here. Interestingly, they didn't mention needing to replace the serpentine belt or the rear shock mounts. As far as the heater core, I noticed tonight that the defroster didn't seem to be working properly. The side windows were still really foggy even with the defroster running. Do you think this is a thermostat, ECT sensor or heater core issue?

I haven't done anything with my car yet. My friend let me borrow his OBD scanner. It reads the coolant temperature. The coolant temperature is reading about 237 degrees at it's high point with the A/C running full blast. I ran the heat at full blast and the coolant temperature started to drop. The red temperature light has never come on. Does this indicate a heater core issue or could it still be the thermostat and ECT sensors?

 

[Kedis82ZE8]

@Mazdiod2 Please do not dump coolant into any drains, flushing, etc. Please Recycle it

 

[Mazdiod2]

I think these modern coolants (OAT) can be cleaned and reused as they have a very long life. I guess the Mazda FL-22 is deficient in rust inhibitors but I think it can be re-used. I don't live in Pueblo although I have been to the recycling place they don't want coolant. They have various disposal services but they will charge me because I don't live there. I need to find some place that processes OAT and can reuse it.