What would you do, engine code for Thermostat?

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Yuk

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Edmonton, AB Canada
2007 Mazda 6 2.3L 4 cylinder

Engine light came on after driving 25 minutes on the highway. Engine is running fine. As much as I can tell, fuel economy is normal.

Code indicates a problem with the thermostat. There is heat in the interior and the engine temperature remains normal.

Have now driven about 50-75 km since reseting the light. That car continues to run well.

Question:
Would you change the thermostat now, or wait for the car to show a code again?
 
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I'd get one of those ELM327 dongles, download Torq for my phone, and then see what temp the engine is running at. If not something for the smartphone then something that can read what the ECU thinks the engine is running at.

If the car is overdue for a coolant exchange, or you have other reason to touch the cooling system, then sure, mess with the t-stat. Otherwise I'd wait for the diagnostic tool and confirm it.
 
Originally Posted by Warstud
What Temp is it running ?


Don't have an actual number, just a Hot/cold gauge. The needle has been sitting in the middle the whole time.
 
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Originally Posted by Donald
The thermostat should be considered a maintenance item. I would replace it. It's cheap enough.

Has the coolant been changed recently?


Coolant was probably changed 3-4 years ago (approx. 50,000 km) with a 5 year mix.
 
Which thermostat code is it? Not getting up to temp fast enough?

An ELM327 dongle is inexpensive and in minutes it will let you know if your problem is just a minor "taking too long to get to temp" which can probably be ignored if you need to or if it's something more serious like the temp running too hot or too cold for long periods of time. Many times a high or low temp won't show up on the temp gauge as most modern gauges are just glorified idiot lights (thank you Ford for starting that!) So you might be running 220F, which isn't overheating, but still hotter than the OEM intended and the gauge a lot of times won't reflect that. Same if the engine is running 160F, it's still technically "warmed up" and might show normal on the gauge, but that temp is too cold for the engine to run at peak efficiency.

I consider any coolant temperature problems to be semi-serious and would put thermostat replacement on my high priority to-do list if I were getting a thermostat code.
 
Originally Posted by 92saturnsl2
Which thermostat code is it? Not getting up to temp fast enough?.....
I consider any coolant temperature problems to be semi-serious and would put thermostat replacement on my high priority to-do list if I were getting a thermostat code.


I didn't scan it, the neighbourhood shop diid, so I don't know.

I have the thermostat, so I can change it. Since the light hasn't come on again, I thought maybe I'd wait for a nicer day. It's a tight, knuckle scraping squeeze to get to the thermostat. Serp belt has to come off and the power steer pump has to come out. I'm probably just being lazy.
 
I forget the code, but my Mazda 3 had the same thing, reaching temperature taking too long. I reset it and it came back after few days. The dummy temperature gauge was behaving normally. Change the thermostat. In rare cases it may be the temp. sensor, but most of the time this code is for the thermostat.
 
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Originally Posted by KrisZ
I forget the code, but my Mazda 3 had the same thing, reaching temperature taking too long. I reset it and it came back after few days. The dummy temperature gauge was behaving normally. Change the thermostat. In rare cases it may be the temp. sensor, but most of the time this code is for the thermostat.


If you have thermostat code and the gauge appears normal, 90% of the time it's the "taking too long to reach operating temp" code. Those can be safely ignored, but even though you might not notice it, emissions and fuel economy will suffer, the degree of which depends on how much longer the engine is taking to reach operating temp, if it's even reaching full operating temp at all.
 
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