Replaced coolant thermostat today.

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The check engine light came on 3-4 weeks ago and it was the thermostat. I have noticed the heater was very slow to warm and the new one has made a huge difference. This was on the Focus.
 
I bet gas mileage will improve quite a bit if the problem has persisted for a while. The OBD2 codes usually appear when the car has had three or more warm-ups where temps haven't exceeded 165F.
 
The thermostat failure was due to the 0W-20 AFE. 20W-50 Would have protected the T stat better!
laugh.gif
 
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Originally Posted By: 92saturnsl2
I bet gas mileage will improve quite a bit if the problem has persisted for a while. The OBD2 codes usually appear when the car has had three or more warm-ups where temps haven't exceeded 165F.


Man good thing my cummins doesn't do that. Takes a good 7 miles or 15 minutes of driving to warm up.
 
Originally Posted By: motor_oil_madman
Man good thing my cummins doesn't do that. Takes a good 7 miles or 15 minutes of driving to warm up.


There's a time interval for what the ECU considers a warm-up cycle. If the drive time is under that amount, it's not counted.

Your Cummins has a code for low coolant temp, but likely a much longer time for what it considers a warm-up cycle.
 
Originally Posted By: motor_oil_madman
Originally Posted By: 92saturnsl2
I bet gas mileage will improve quite a bit if the problem has persisted for a while. The OBD2 codes usually appear when the car has had three or more warm-ups where temps haven't exceeded 165F.


Man good thing my cummins doesn't do that. Takes a good 7 miles or 15 minutes of driving to warm up.


Yeah, at this time I hate driving my truck. Takes FOREVER to get heat and warm up. High idle and exhaust brake seems to help a bit. But being deleted really kills the warm up side, I guess that is the one downfall of being deleted.
 
Originally Posted By: CT8
The thermostat failure was due to the 0W-20 AFE. 20W-50 Would have protected the T stat better!
laugh.gif


Exactly what he says, no doubt

Smoky
 
Originally Posted By: Smoky14
Originally Posted By: CT8
The thermostat failure was due to the 0W-20 AFE. 20W-50 Would have protected the T stat better!
laugh.gif


Exactly what he says, no doubt

Smoky


Nah, Lucas oil stabilizer would win on this one.
 
I had the same thing happen about a year ago in my Mazda 3. The coolant temp needle operated as normal, even the heat seemed about the same, but the check engine light came on.
It's pretty neat because it can take along time to see the low temperature on the dummy gauge, which means getting worse fuel economy. The ECU can detect this much faster.
 
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I replaced the thermostat in my 2.3 Mazda a couple months ago. It seems to be a known problem with these duratec engines. My engine temp rarely went over 170f (scanguage II) and gas mileage dropped to 25-26 mpg. Now I get 27-29 depending on how much A/C I use. What brand thermostat did you buy? I ordered an OEM Mazda from Amazon.
 
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I still have the original thermostat on my Grand Am. Its been bad for 5 years now. If we are going to have a long stretch of cold weather I just put a piece of cardboard over the radiator. Sometimes I will have to pull over after driving 10 minutes just so it hits that 190 degree mark. If I don't pull over and don;t let it hit 190 degrees, then I start getting codes(temp gauge wont work and cooling fan will stay on until computer is reset).
 
Originally Posted By: mike7139
I still have the original thermostat on my Grand Am. Its been bad for 5 years now. If we are going to have a long stretch of cold weather I just put a piece of cardboard over the radiator. Sometimes I will have to pull over after driving 10 minutes just so it hits that 190 degree mark. If I don't pull over and don;t let it hit 190 degrees, then I start getting codes(temp gauge wont work and cooling fan will stay on until computer is reset).



And you haven't replaced a $5 thermostat why?
 
How hard was it to replace on your 2007. I got a text from my mechanic that it was a major PITA with all the stuff that had to come off.

DEFINITE improvement on my Focus.

Which temp did you go with?
 
Originally Posted By: Miller88
How hard was it to replace on your 2007. I got a text from my mechanic that it was a major PITA with all the stuff that had to come off.

DEFINITE improvement on my Focus.

Which temp did you go with?


It is hard to get to. I have a bad left hand that was crushed 14 years ago, so it can't manipulate tools it tight places the way I once could. So I had the thermostat done at a local garage, but do not know what brand it was. Seems to be working well at this time.
 
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