2018 CX-9 Overheating
- Thread starter chris76
- Start date
You would think that Mazda would want to offer an incentive to buy their products, being that they are a small company. Service advisor told me that he had another customer with an engine that was just past the 60k powertrain warranty, and Mazda was giving him a difficult time with covering the classic TSB 01-012/21 cracked cylinder head failure with external coolant leaking (which was slightly different than my car's issue.) If you're reading this, Mazda USA, this is not a good way to make first time Mazda buyers (like us) repeat Mazda buyers. I wonder how many of these 2016-2018 (and perhaps later) 2.5Ts had bad casting. I'm beginning to think it's a huge percentage. I'd never buy one on the used market.
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- 2017 CX9 GT AWD
I've owned three Mazdas, but my 2017 had the coolant leak. It was within warranty so Mazda did cover it with a new engine. I love the CX-9, but it bugs me with such a major defect they're not covering their own engineering mistake even out of warranty. They should step-up and just do it, no questions asked.
Mazda posted a loss, and a rather sizable one at that, in their most recent quarterly results posted on June 30. The blame was pinned on production shortfalls, but one can't help but wonder how much warranty claims are hurting their bottom line.
The company announced price hikes across the board. I suspect Mazda Corporate will be increasingly stingy if their profitability does not improve. Their next quarterly update is due at the end of September...
Jack Rabbit
Banned
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- 18 Mazda CX5 AW
But these cracked cylinder heads that are showing up shouldnt be across multiple years. Where was the quality control?
They designed a high pressure high temp engine and then apparently the bolts were overtorqued causing micro-cracks which eventually expand to become a problem, hopefully before the warranty is expired. And the high pressures will only exert more force on an already defective head.
I've seen comments on 2014 to 2019 having these cracked cylinder heads across the CX5 and CX9 platforms. At what points did they check the robotic torque machines?
I've never had a non-mazda vehicle crack a head.
It's just not that common on passenger vehicles. Cracked heads usually only occur on race cars and very old vehicles.
They really should have been on top of this. Especially since this was designed as a high pressure engine... Last things you need is a weak cylinder head.
I don't think you can conclude this problem was due to over-torquing bolts, although it may have contributed. Mazda changed the head design to mitigate the problem. If it was solely down to a bolt torque issue, they would not have required a head casting change.
As far as how this could slip past QC:
1. It took several years of service before these issues started appearing. I'm sure Mazda did some sort of life testing, but it may not have reproduced the combination of heat cycles, mechanical loading, and other effects that real life use placed on the cylinder head.
2. The prototype and qualification blocks and heads were likely cast in a different foundry and then post machined in a different shop than the production blocks and heads. Small differences in alloy composition, mold fabrication, melt pour, post heat treatment and other processing could have yielded different material properties in the metal. It's possible that the testing blocks all passed with flying colors, only for the production blocks to have slightly different material properties which led to the cracking issues now.
And head cracking is a lot more common than you seem to think. If you crack open a Subaru block, for instance, they are notorious for cracking from the spark plug hole to one of the exhaust valves. However, the crack doesn't penetrate the water jacket so most people remain blissfully unaware that there is any issue. Honda has also had an engine or two where this was not unheard of, but again, most people would not realize there were any cracks.
I just went through this myself. I was at 60.5 months and 59,780 miles on my 2017. Noticed a strong coolant smell during a cold start when backing out of the garage. Scheduled an appointment with the selling dealer for diag. They found that coolant was leaking internally into the cylinder after pressure testing the cooling system. No overheating, no misfire codes. No signs of external leaks anywhere. Oil was not contaminated since the leak was still in the early stages.
The selling dealer also included 100k power train with all vehicles they sell. I paid a total of $350 deductible for the repair. The extended powertrain warranty verbiage stated a $200 a deductible. Apparently my service records of parts receipts and spreadsheet of what was done with the mileage was not acceptable.
Not sure exactly between the dealer and mazda who paid for what. New cylinder head, water pump and all associated gaskets in the TSB was replaced. Total time was just over a week.
Jack Rabbit
Banned
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- 18 Mazda CX5 AW
Thanks for explaining the manufacturing process. It's nice to learn how things are made.
Still, the broken head wouldn't exist without both a & b. A strong head could take some overtorque while correct torque on a weak head might be as ok as well.
Both appear to have contributed to the problem.
Didnt the TSB say overtorque caused the problem hence the redesigned head ?
the cracked head is both a design flaw and a manufacturing flaw.
I haven't owned a subaru so am not familar with their engine problems.
However have owned many fords and toyotas without any engine problems that lasted for 14 + years. Likewise I dont know of anyone else who had these kinds of engine problems with fords or toyotas.
The Mazda is a nice car and handles well and looks great. But at the end of the day, imo, it appears problems like these(and not standing behind the defective product past the warranty period) is what prevents it from being a Top 10 car maker.
Maybe Toyota can help them with quality control at the new toyotas/mazda plant.
Hopefully Toyota learned it's lessons after the gas peddle problems.
The only things we can do to protect our investment before warranty expired is have an ultrasound inspection or other test to find the micro-cracks and prove defective so they'll replace the head. Because theyve clearly taken a catch me if you can position.
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Created an account to say our situation is identical in nearly every way to yours. 2018 Mazda Signature. 75k miles. Geico mechanical insurance paid for the fix, but the “fix” was resurfacing, because they mechanic saw no evidence of cracked cylinder head as indicated by the service bulletin.
Well, collected my car, it’s still overheating. They said there was air in the line, so they drained it. Collected and it’s still overheating. They’ve changed the thermostat. Collected and it’s still overheating.
Dropping again off on Monday (4th time).
We loved this car. But I’m done. Mazda btw didn’t do s***. They should replace the motor.
Hello, I'm new to this forum, I have a Mazda, 2018 CX- 9 Touring,. I bought it certified pre-owned from Mazda, I've had it 4 years, driven 80k miles, total miles now are 126k. I take it to Mazda dealership for all maintenance. I noticed the heater not working properly, so I immediately checked the coolant level and it was almost empty. I never had lights come on to alert me of any problems, so I immediately took it to the dealership, and they replaced the thermostat, and said problem fixed!
A few weeks later, Heater not working again, and coolant low again, so I took it back to dealership, and after 3 hours, the technician said he ran all tests, can't find any problems, and the heater is working fine. As I was driving, 3 weeks later, my first warning light lit up, and flashed an alert saying "coolant low, pull over." I immediately pulled over and had it towed back to the Mazda dealership, This is the 3rd time at Mazda for the same overheating issue! The technician said he was in contact with Mazda corporate, daily, to help him find the issue. On day 7, They finally decided there is a crack and I need a new engine!, I'm noticing many others with the exact same problem that I have, and there is a TSB out on similar, if not same issue. I would think there would be a recall out on something like this? ! I have spoken with Mazda Corporate and have a claim #, and should hear back from them within 4 to 5 days. I still owe $8,000 on the vehicle, and the estimate Mazda gave me, for a new engine, is $10,000. Also, I feel the need to mention that the Mazda dealership, working on my vehicle, only has one mechanic (short staffed). At the very least,, with an issue this big, a second person should inspect it,, I'm stuck without a vehicle as I cannot afford to pay it off, and get a new engine. Any information, or suggestions, would be greatly appreciated! Thank you for taking the time to read,
A few weeks later, Heater not working again, and coolant low again, so I took it back to dealership, and after 3 hours, the technician said he ran all tests, can't find any problems, and the heater is working fine. As I was driving, 3 weeks later, my first warning light lit up, and flashed an alert saying "coolant low, pull over." I immediately pulled over and had it towed back to the Mazda dealership, This is the 3rd time at Mazda for the same overheating issue! The technician said he was in contact with Mazda corporate, daily, to help him find the issue. On day 7, They finally decided there is a crack and I need a new engine!, I'm noticing many others with the exact same problem that I have, and there is a TSB out on similar, if not same issue. I would think there would be a recall out on something like this? ! I have spoken with Mazda Corporate and have a claim #, and should hear back from them within 4 to 5 days. I still owe $8,000 on the vehicle, and the estimate Mazda gave me, for a new engine, is $10,000. Also, I feel the need to mention that the Mazda dealership, working on my vehicle, only has one mechanic (short staffed). At the very least,, with an issue this big, a second person should inspect it,, I'm stuck without a vehicle as I cannot afford to pay it off, and get a new engine. Any information, or suggestions, would be greatly appreciated! Thank you for taking the time to read,
Yes, you most definitely have a cracked cylinder head causing the coolant leak. You have 2 options because the chance of Mazda paying for any part of the repair is pretty much gone at your mileage.
1) Trade in the way it is to another Mazda dealer and purchase a new one of the same or trade in at another brand dealer. You can also sell direct to carmax, carvanna, vroom etc and get a check for the difference of what is offered and what you owe and they will pay it off. You can also trade in at those places as well.
2) Check the oil dipstick and see if it looks like any coolant made it into the crankcase and mixed. If the oil looks like a milkshake, you are done and need a new engine. If it looks like regular oil color and consistency then you got lucky and ONLY need a new head which is much much less expensive. An indy repair shop can do it or dealer can. A new revised head is under $1k plus a lot of labor.
Hope that helps.
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Anytime! 🙂
Btw welcome to the forum, we are all here to help one another and collectively share our knowledge, enthusiasm and experience for all to learn and help solve problems while enjoying what we love to drive.
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Brandi, first, get your money back for the first two services. They did not fix your problem, which was the cracked and leaking cylinder head. It certainly was not a bad thermostat.
If you trade the car in, have a different shop flush the radiator then refill with the correct Asian green antifreeze (doesn't need to be Mazda branded) and some stop-leak compound. Have them rinse any old dried coolant off the back of the engine under the leaking spot. Then promptly trade it in. Have the oil and filter changed as well after the stop-leak is added. I'd look for a dealership group that has both a Mazda franchise and other brands, and trade it at one of their other brands.
Interest rates are high, so car payments are high. Used car prices have started to drop very slightly, but they're still high. Good luck.
If you trade the car in, have a different shop flush the radiator then refill with the correct Asian green antifreeze (doesn't need to be Mazda branded) and some stop-leak compound. Have them rinse any old dried coolant off the back of the engine under the leaking spot. Then promptly trade it in. Have the oil and filter changed as well after the stop-leak is added. I'd look for a dealership group that has both a Mazda franchise and other brands, and trade it at one of their other brands.
Interest rates are high, so car payments are high. Used car prices have started to drop very slightly, but they're still high. Good luck.
Thank you so much for your helpful information!
It's a breath of fresh air to have you kind people helping out this stranger 🙂.
I also feel I should get a refund on services performed that were not needed, so thank you for reinforcing that!
A friend mentioned a stop leak compound, but I was apprehensive, so I will definitely look into that. Mazda tells me I can only use their brand coolant, but I did use one I bought at advanced auto, and I made sure it was correct, as did service.
We can now sadly say goodbye to the good old days of low interest rates, I was enjoying my 1.9% rate, until my vehicles early demise! Thanks again, I will use the information you shared, and am grateful.
Asian vehicle green coolant is available from several makers including Prestone and Valvoline's Zerex (and NAPA labeled). It is probably chemically the same as the Mazda green stuff. I buy the Zerex Asian green for my Mazda and Asian red for my Toyota, because that's easiest for me to buy.
2016 CX-9 with 91,000 miles.
I noticed the coolant level in the tank was consistently low, even after adding more. After a week of repeatedly topping off the coolant every other day, I removed the engine undercover and discovered a messy green residue all over the place. I contacted MazdaUSA and confirmed that my 2016 CX-9 is still covered under the CPO Limited Powertrain Warranty until 7/28/23 or 100,000 miles, which is just about another two months in my case. Initially, I suspected a leaking water pump or gasket when I brought it to my local dealer. However, they informed me that it's actually a crack in the cylinder head. Fortunately, this issue will be covered by my CPO warranty, but I'll have to wait for a week to get the replacement part. In the meantime, I'm using the dealer's courtesy vehicle for free since the loaner car is not covered by Mazda. I'm uncertain about how long I should remain optimistic. I had plans to continue driving my CX-9 for a long time, but now I'm not sure what to expect.
I noticed the coolant level in the tank was consistently low, even after adding more. After a week of repeatedly topping off the coolant every other day, I removed the engine undercover and discovered a messy green residue all over the place. I contacted MazdaUSA and confirmed that my 2016 CX-9 is still covered under the CPO Limited Powertrain Warranty until 7/28/23 or 100,000 miles, which is just about another two months in my case. Initially, I suspected a leaking water pump or gasket when I brought it to my local dealer. However, they informed me that it's actually a crack in the cylinder head. Fortunately, this issue will be covered by my CPO warranty, but I'll have to wait for a week to get the replacement part. In the meantime, I'm using the dealer's courtesy vehicle for free since the loaner car is not covered by Mazda. I'm uncertain about how long I should remain optimistic. I had plans to continue driving my CX-9 for a long time, but now I'm not sure what to expect.
