Warranty extension for fail-safe thermostat

[yrwei52]

Maybe @badanth has a 2024 NA model that does not have CD?

it’s possible. But we don’t know if those 2.5L NA’s in 2024 CX-5 has all the CD plumbings (hence it has collar control valve) but got disabled by the software, or it’s the previous 2.5L NA used in 2017 or prior CX-5’s. The VIN could have indicated the existence of the CD, but we still don’t know how the Mazda handles this. The latest TSB does say 2024 CX-5 has coolant control valve.

TSB No.: 01-005/24 Check Engine Light On with DTC P0126:00

 

[badanth]

That is correct!

 

[stickerbush]

My 2024 NA with no CD seems to have a problem keeping the motor at a constant temperature. Starting from cold the needle will fairly quickly rise out of the blue area then to the hash mark between 120 and 210, then it will creep back down 20 or 30 degrees. Then it will go back up a bit. It continues going up and down, even once it reaches the fully warm temperature just below the 210 mark. This is observed while driving on 40mph rural roads in 70F degree ambient temperature.

I've had the car a bit over a year, don't think it behaved this way when I got it, I recall the gauge steadily rising to just below 210 and then staying there, steady as a rock. I could be remembering my 2020 though.

This isn't normal is it?

 

[stickerbush]

My 2024 NA with no CD seems to have a problem keeping the motor at a constant temperature. Starting from cold the needle will fairly quickly rise out of the blue area then to the hash mark between 120 and 210, then it will creep back down 20 or 30 degrees. Then it will go back up a bit. It continues going up and down, even once it reaches the fully warm temperature just below the 210 mark. This is observed while driving on 40mph rural roads in 70F degree ambient temperature.

I've had the car a bit over a year, don't think it behaved this way when I got it, I recall the gauge steadily rising to just below 210 and then staying there, steady as a rock. I could be remembering my 2020 though.

This isn't normal is it?

Any comments on whether this behavior is normal?

I got the letter about warranty extension. 2024 without CD, no check engine light, no stored DTCs.

 

[elementCX5]

Any comments on whether this behavior is normal?

I got the letter about warranty extension. 2024 without CD, no check engine light, no stored DTCs.

Mine did something similar, but not quite as bad. It would go up to 210, then creep back down to around the 1/3 mark sometimes. Usually when cold out.

What finally triggered the CEL for me was taking it on the highway. I work right next to one and take it home. The car warmed up1/4-1/3 of the way and stayed there for a solid minute before it started creeping towards 210f. It was Maybe 45⁰f out when this happened IIRC. When it stayed stuck for that minute is what finally triggered the CEL.

Maybe the computer has to see that the car has been steady accelerating, hit X speed, but coolant temp hasn't increased in X time to throw a code? I really don't know what parameters have to be met to help you there as it just seemed like dumb luck for my car.

Since I've got the Thermostat replaced, it hasn't been as cold out, but the car will always warm up to 210⁰f and then stay one notch below, or at 210⁰f. It doesn't go up and down like it used to. Hope that helps..

 

[stickerbush]

I spoke with dealer and they agreed to have a look at it, will bring it in tomorrow. I have had good service with this dealership in the past.

I know the TSB requires CEL for warranty extension but since my car is still under warranty I will argue that the problem should be remedied even in the absence of CEL as something is clearly wrong with coolant temperature regulation. Maybe that logic doesnn't make sense...I just don't want to end up having to deal with it when I'm on a long road trip in about 6 weeks from now.

 

[stickerbush]

I spoke with dealer and they agreed to have a look at it, will bring it in tomorrow. I have had good service with this dealership in the past.

I know the TSB requires CEL for warranty extension but since my car is still under warranty I will argue that the problem should be remedied even in the absence of CEL as something is clearly wrong with coolant temperature regulation. Maybe that logic doesnn't make sense...I just don't want to end up having to deal with it when I'm on a long road trip in about 6 weeks from now.

Dealer just called and said that technician found that there was a problem with the thermostat and they will be replacing it under warranty. That's about all I know at this point, will update if/when I have more information.

There was no CEL displayed.

 

[stickerbush]

 

[kdaug]

I just received the letter from Mazda (Canada) so dropped in to see what my dealership was experiencing. They have already replaced a few thermostats, but confirmed that they would only replace mine, when, and only when I got the designated CEL error code. They said to just file the letter away and keep an eye out for the CEL in the future. I have yet to experience any unusual temperature gauge readings.