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Discussion Starter #1 (Edited)
I live in Michigan and the temp has dropped a lot lately but my temp gauge barely gets up above a quarter of the way I have the radiator kinda blocked with a piece of cardboard meaning its about 6 inches from the radiator is it normal to run this cool on the highway or with the heat on? The reason I ask is my gas mileage has ranked on the highway

This is cruising on the highway


And this is sitting idling and sometimes during city driving with the heat off.
 

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Looks normal to me.

I was running temps like that during the summer.

If you think those are too cool you should see mine right now. I think my thermostat is stuck open, it takes forever to build up some heat in the heater, and it barely reaches 160 even after cruising around for a while.

Did you install the cardboard because it wasn't building up temperature?
 

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OEM LOL
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Sounds like your thermostat failed.

Most thermostats have a fail safe so they fail open instead of closed. That way you dont overheat your motor and blow it.
 

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Could be, but this time of year in MI, I wouldn't expect it to get that warm anyway. How long does it take to get to that temp?
 

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Discussion Starter #6
Yeah that's what I was wondering because its pretty nippley up here but it takes it a pretty decent amount of time to warm up like a good ten miles if I get straight on the highway before I added the cardboard my highway temp was directly at the quarter mark and city driving I could get to where it is now when I cruise on the highway with the radiator block. My thing is I don't understand I literally have the whole radiator blocked granted towards the bottom there's about a 6 inch gap between the radiator and the cardboard. I've had the thermostat replaced 3 times already so I was wondering if it failed again but if you all say its normal I'll just live with my mpg drop til summer. The heat coming out of the vents is just under 160 degrees
 

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I changed my thermostat last night. I knew my old one was stuck open because when I would start up the car (cold), as it warmed up I could feel the heat build up in the upper radiator hose.

Swapped in the new one (195F OEM) and I could feel that the thermostat was doing its job and staying closed until engine warmed up to 180F I believe.

Now, regardless of street/fwy my operating temp is pinned right at about 190, about where your 2nd photo indicates.

Heater works extremely well now too.
 

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Discussion Starter #9
I changed my thermostat last night. I knew my old one was stuck open because when I would start up the car (cold), as it warmed up I could feel the heat build up in the upper radiator hose.

Swapped in the new one (195F OEM) and I could feel that the thermostat was doing its job and staying closed until engine warmed up to 180F I believe.

Now, regardless of street/fwy my operating temp is pinned right at about 190, about where your 2nd photo indicates.

Heater works extremely well now too.
It's a factory temp thermostat. So would you think mine is stuck open?
 

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OEM LOL
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I would say yes but if you have had it replaced 3 times.

Either there is some corrosion or something blowing your thermostats
Or
The thermostat isnt the problem.

Have you ever had the coolant flushed or anything.
 

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Discussion Starter #11
I would say yes but if you have had it replaced 3 times.

Either there is some corrosion or something blowing your thermostats
Or
The thermostat isnt the problem.

Have you ever had the coolant flushed or anything.
Yes it has been flushed every time the shop replaced them the first two failed within 2 weeks of each other the place they ordered from had faulty parts they are a very reliable shop the coolant was flushed more than once when the coolant elbow broke 3 times too haha. I've had absolutely nothing but problems with this car.
 

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My impala did the same same thing a couple weeks ago. It wouldnt ge tup to temp and the gas mileage went way down. The car knew it wasnt getting up to temp so it was feeding it self a richer mixture of gas. Upon initial start ups you could smell it was rich. Once i changed my thermostat the mileage was even better than before and i had better heat.
 

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OEM LOL
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I really think its the thermostat even though after 3 flushes and three thermostats it keeps happening and it shouldnt be.

Maybe try a different shop or use a oem thermostat like ac delco
 

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It's a factory temp thermostat. So would you think mine is stuck open?
There is one way to be sure: Start the car cold and constantly monitor the upper (driver side) radiator hose as the engine warms up.

If the hose slowly becomes warm while the car warms up: stuck thermostat

If the hose stays cold while the car warms up and when the temp needle reaches about 180ish it becomes instantly hot: good thermostat

I use my hand to feel for warmth, or you can use a laser thermometer if you have one.

I'd also agree that if you are blowing thermostats on a regular basis there is something else to look for. Ironically, my thermostat failed after I put some stop leak stuff in my radiator on my last long distance trip. We'll see how long this one lasts as I've yet to do a flush.
 

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Just got done flushing out my cooling system this past weekend because my heater wasn't working as well as expected and the anticipated outside temperature dip deep. (-5 as it turned out).
First I disconnected the heater core hoses and flushed them out in both directions. I got some cruddy water/coolant the first two times but ran clear the third time. Next I looped a piece of hose from the water pump outlet to the water pump inlet. Then I removed the radiator cap, the T-stat and drain plug and captured the coolant in a pan. Placed the cap and plug back into their respective places. Next I filled the radiator with water from the garden hose in my garage. Ran the engine with the heater set to wide open (or number five) until it got up to temp. Allowed engine to cool. Removed the radiator cap and plug, drained into pan three times. By this time the water/coolant mixture was pretty clear.
With the radiator empty I put the plug into radiator and a new NAPA brand 195 degree T-stat in the motor. I filled it with distilled water (1 1/2 gals) I removed the temperary hose from the water pump and connected the two heater core hoses back to their original locations. Next I started the engine with the heat on and waited for it to get up to temp again adding water as needed. Let engine cool and drained again.
During the time the engine was warming up and then draining I had removed the coolant overflow tank and cleaned out all of the crap inside and placed it back to its original location.
After all this I filled the coolant overflow tank with Prestone extended life antifreeze/coolant (150,000mi/5years) to the cold markings then added another 1 1/2 gals of Prestone to the radiator. I opened the pet cock on top of the T-stat housing elbow, blocked the rear tires and raised the front end of the vehicle about a foot. Next I started the engine and waited for the water to stream constantly out of the T-stat petcock at which time I closed it tight. I continued to monitor the fluid level in the radiator and added distilled water until the T-stat opened and the radiator was full.
Now my car throws heat as if it was in AZ on the 4th of July. Good thing because like I said it got down to 5 below zero 36 hours later.
Thanks to Kingnutin.
 

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If that don't do it, nothing will!
 
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