The wifes 2008 Mazda5 started over heating last night on the way home, looks like the thermostat is stuck so its being towed to the dealer for repair. I traded cars with her last night so she could take the baby home. I didn't think 100 degrees F would be good for a 4 month old. On the upside the heater was working great hense the 100F interior temps. I was able to keep the temps down with the heater at full blast and all the windows down.
Mazda5 overheating 2.3L MZR engine.
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I must say I notice there are a lot of very lousy T stats hitting the market. In new cars and on the parts rack.
Let us know if confirmed.
Let us know if confirmed.
Clue me in also 
T-stat bad is my bet, too.
Originally Posted By: glennc
Very interesting conjecture. Mentally noted for future reference.
I'd also like to know if it turns out to be the case. Does seem like the most likely cause on an new car like that.
I'm pretty sure thats what it is, this isn't my 1st experience. The water pump was clearly not missing its impeller since I was able to cool the engine using the heater core which shows we still have coolant flow. Once the engine was cooler around 209F the radiator fan was still running and blowing only cool air which is evident of an obstruction in the cooling system since the airflow was clear. The only mechanical obstruction in the cooling system is the thermostat. The only other option is an obstruction else where in the system, plugged radiator (unlikely) or radiator hose/block passage. Last option would be an air bubble at the thermostat which again is unlikely after more then 2000 miles in a closed system.
I called the service manager and it will be tomorrow before they get to the car. FYI the wifes last van an 04 Sedona also had a stuck thermostat except she was hundreds of miles from the house at the time, same situation. I agree with Pablo it seems odd for 1 person to have the same problem twice in 3 years unless the parts are lower quality then they should be.
Very interesting conjecture. Mentally noted for future reference.
I'd also like to know if it turns out to be the case. Does seem like the most likely cause on an new car like that.
I'm pretty sure thats what it is, this isn't my 1st experience. The water pump was clearly not missing its impeller since I was able to cool the engine using the heater core which shows we still have coolant flow. Once the engine was cooler around 209F the radiator fan was still running and blowing only cool air which is evident of an obstruction in the cooling system since the airflow was clear. The only mechanical obstruction in the cooling system is the thermostat. The only other option is an obstruction else where in the system, plugged radiator (unlikely) or radiator hose/block passage. Last option would be an air bubble at the thermostat which again is unlikely after more then 2000 miles in a closed system.
I called the service manager and it will be tomorrow before they get to the car. FYI the wifes last van an 04 Sedona also had a stuck thermostat except she was hundreds of miles from the house at the time, same situation. I agree with Pablo it seems odd for 1 person to have the same problem twice in 3 years unless the parts are lower quality then they should be.
is it bad to drive with a thernmostat stuck open? I believe it is stuck open on my car, as it takes awhile to warm up and goes almost ice cold on the highway even during 70 degree days.
Originally Posted By: parimento1
is it bad to drive with a thernmostat stuck open? I believe it is stuck open on my car, as it takes awhile to warm up and goes almost ice cold on the highway even during 70 degree days.
Yes. But not as bad as driving with a stuck closed stat.
is it bad to drive with a thernmostat stuck open? I believe it is stuck open on my car, as it takes awhile to warm up and goes almost ice cold on the highway even during 70 degree days.
Yes. But not as bad as driving with a stuck closed stat.
Thermostat is most likely, but an inoperative cooling fan, bad pump, pump drive belt system, or low coolant or air pockets, may have to be checked out.
Cars done, 1 new thermostat and an oil change. I'll try and pick it up tonight but the dealership is about 60 miles 1 way. I am also going to find out what brand of oil they use for my planned UOA after a few thousand miles.
Oil change is free from the dealer as the 1st service.
Oil change is free from the dealer as the 1st service.
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Glad it was so simple!
if they are like us Motorcraft bulk oil. we keep the mazda stuff in bottles for warranty purposes.
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