My Mazda 3 got a first CEL

Status
Not open for further replies.
Joined
Dec 23, 2006
Messages
12,373
Location
Canuck - moved to —> California —> Texas —> ???
Yup, it finally happened after 7.5 years and 110k miles. About two weeks ago my wife informed me that the CEL light came on. I disconnected the battery and the cel went away for over a week. Few days ago the cel came back and I knew that it must be coming on for a reason.
As my luck would have it, CT has a 50% off sale for their OBD2 scanner, so I got it for a $100 which is not bad considering it has few extra features such as data logging and ABS codes.
Anyway, the code is P1026 and it's insufficient coolant temp. which means I need a new thermostat. The car warms up as usual and the temp. needle always reaches the usual centre position. So there are no other indication of the thermostat being stuck open.

This brings me to another point. And it is about some members mantra of changing thermostats when certain mileage is reached. Well, in any modern car it is totally not needed because the car will detect longer warm up times far sooner that the driver looking at the dummy gauges. This pretty much removes all guess work and unneeded part changes. Neat if you ask me.
 
Last edited:
Kris, If you will need some deeper diagnostics please let me know ...
I have hardware that does it on dealer level.

I'm in TO from time to time....

Good luck!
 
Last edited:
Originally Posted By: KrisZ
Yup, it finally happened after 7.5 years and 110k miles. About two weeks ago my wife informed me that the CEL light came on. I disconnected the battery and the cel went away for over a week. Few days ago the cel came back and I knew that it must be coming on for a reason.
As my luck would have it, CT has a 50% off sale for their OBD2 scanner, so I got it for a $100 which is not bad considering it has few extra features such as data logging and ABS codes.
Anyway, the code is P1026 and it's insufficient coolant temp. which means I need a new thermostat. The car warms up as usual and the temp. needle always reaches the usual centre position. So there are no other indication of the thermostat being stuck open.

This brings me to another point. And it is about some members mantra of changing thermostats when certain mileage is reached. Well, in any modern car it is totally not needed because the car will detect longer warm up times far sooner that the driver looking at the dummy gauges. This pretty much removes all guess work and unneeded part changes. Neat if you ask me.


There may be more than one temp sensor. I would verify that before changing the thermostat.

And some people consider a thermostat a maint. item and replace every 3-5 years. Its important for the engine to run at the designed temp. Rather than replace it only if it overheats or you get no heat in winter.
 
I used to replace the t-stat at every timing belt change on the old Accord (90-100K miles). Not a bad scheduled maintenance item, actually.
 
There might be another sensor, but 99.99% of the time it is the t-stat. The factory one comes with the housing, sensor and gasket all as one piece ready to put in. I sell a ton of these.
 
I've put a TON of thermostats into Mazda 3's to correct the same code. It seems like every other check engine light on a Mazda 3 that rolls into my bay is the P1026. Order from dealer and you'll get entire assembly, 30 minute job. Good idea to replace your serpentine belt and tensioner if needed, as both are coming off.
 
Originally Posted By: ComfyShorts
I've put a TON of thermostats into Mazda 3's to correct the same code. It seems like every other check engine light on a Mazda 3 that rolls into my bay is the P1026. Order from dealer and you'll get entire assembly, 30 minute job. Good idea to replace your serpentine belt and tensioner if needed, as both are coming off.


The serp. belt was changed last summer, however I think the tensioner has to be changed because it shifts slightly to the left under tension and it's not perfectly aligned, therefore I get a slight belt squeak when cold.
I think I'm going to leave this job for early spring and change the thermostat housing, the tensioner and drain and fill the coolant while I'm at it.

Also, I read somwhere on Mazda forums that the thermostat and the housing were revised several times over the past few year. Do you know if the new thermostat holds up longer? Did you have to change the revised one yet?
 
You have the scanner with the data logging. So you look at the live data to actually find the coolant temperature before deciding to buy a new thermostat.
 
Last edited:
Originally Posted By: KrisZ

Also, I read somwhere on Mazda forums that the thermostat and the housing were revised several times over the past few year. Do you know if the new thermostat holds up longer? Did you have to change the revised one yet?


I haven't had to replace a revised thermostat yet.
 
Update:

I changed the thermostat this morning. Nothing really to report other than the job is not difficult, but a bit time consuming because of the location of the thermostat.
The new thermostat does look a bit different and better made, so let's hope it's the last one I change.

Here is the old one.


And the new one.

 
Status
Not open for further replies.
Back
Top