How often are new thermostats bad?

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CorDog009

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Replaced the water pump and radiator, installed a new 190* thermostat instead of the 203 that was stock. Put truck on ramps to help burp any air out of the system. Truck finally got to operating temp with no more bubbles coming out. Put radiator cap back on and let it run a little longer, then noticed temp gauge climbing past halfway, got close to 3/4 of the way in the black operating range and I shut it off. T-stat to radiator hose isn’t very warm. Radiator has some heat but not hot. I’m thinking I got a bad new thermostat.
 
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CorDog009

CorDog009

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Purged a good bit more air out of it after I took it off the ramps. Fingers crossed.

Topped it off and let it run, upper radiator hose finally got hot so I knew thermostat was open. Temp settled below halfway and staying there. Seems to be fine now.
 
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Different Drummer

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Purged a good bit more air out of it after I took it off the ramps. Fingers crossed.

Topped it off and let it run, upper radiator hose finally got hot so I knew thermostat was open. Temp settled below halfway and staying there. Seems to be fine now.
Did you happen to notice any drop in Engine oil Temp. and Transmission fluid Temp. with the 190* degree thermostat?
I assume the running stabilized engine coolant Temp. was reduced?
Edit: any problems with weird codes etc?
 

Snake15eyes1998

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Did you happen to notice any drop in Engine oil Temp. and Transmission fluid Temp. with the 190* degree thermostat?
I assume the running stabilized engine coolant Temp. was reduced?
Edit: any problems with weird codes etc?

The tranny temp won't change with a lower thermostat. Its all independent on these trucks. The transmission oil doesn't run into the radiator, oil temp i don't think would change either.
 

Different Drummer

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The tranny temp won't change with a lower thermostat. Its all independent on these trucks. The transmission oil doesn't run into the radiator, oil temp i don't think would change either.

The oil cooler on my 3.6 is a fluid to fluid heat transfer device ( heat exchanger ) with the engine coolant. So, theoretically if the engine coolant Temp. is reduced the oil Temp. would be reduced also. Maybe the 5.7 has a different way of cooling engine oil.

On the transmission, yes the Trans. fluid is cooled via the cooler in the top of the A/C condenser. In this instance using air flow as a cooling mechanism. However, before it gets to the transmission innards it is routed through another fluid to fluid heat exchanger that uses engine coolant to add heat to the transmission fluid. Again in theory if the engine coolant is cooler it would have less capacity to add heat to the transmission fluid.
I was wondering if in actual practice there was any measurable change in Temps.
 

pacofortacos

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The tranny temp won't change with a lower thermostat. Its all independent on these trucks. The transmission oil doesn't run into the radiator, oil temp i don't think would change either.


It will drop once you drop to a 160 deg. thermostat anything above that it doesn't affect the trans temp really at all.
 

pacofortacos

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Did you happen to notice any drop in Engine oil Temp. and Transmission fluid Temp. with the 190* degree thermostat?
I assume the running stabilized engine coolant Temp. was reduced?
Edit: any problems with weird codes etc?

On the 3.6 truck, unless you removed some of the AGS shutters, I don't think you would see much of a change in temperatures other than wider temp swings as the shutters will control the temp.
You might see a bit cooler temps with the AC on as it will turn on your fan and open the shutters more often.
I don't think much change in oil temps will be seen.
 

Snake15eyes1998

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The oil cooler on my 3.6 is a fluid to fluid heat transfer device ( heat exchanger ) with the engine coolant. So, theoretically if the engine coolant Temp. is reduced the oil Temp. would be reduced also. Maybe the 5.7 has a different way of cooling engine oil.

On the transmission, yes the Trans. fluid is cooled via the cooler in the top of the A/C condenser. In this instance using air flow as a cooling mechanism. However, before it gets to the transmission innards it is routed through another fluid to fluid heat exchanger that uses engine coolant to add heat to the transmission fluid. Again in theory if the engine coolant is cooler it would have less capacity to add heat to the transmission fluid.
I was wondering if in actual practice there was any measurable change in Temps.


On these years of hemi. The transmission cooler is a separate deal. It sits right in front of the ac condenser. Its 100% separated from any engine coolant. They did that to avoid cross contaminating, if that where to happen. Never understood why some vehicles have it routing into the radiator then to a aux cooler. If living in super cold climate, i get it. But for the most part. Just a big cooler, separated from all engine coolant in my opinion, should be sufficient to cool. Just add an inline thermostat and until the tranny reaches your desired temp. It won't run through the cooler. That's better than having it run through the radiator in my opinion because then you run the risk of cross-contamination fluids as the vehicle ages.
 

Different Drummer

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On these years of hemi. The transmission cooler is a separate deal. It sits right in front of the ac condenser. Its 100% separated from any engine coolant. They did that to avoid cross contaminating, if that where to happen. Never understood why some vehicles have it routing into the radiator then to a aux cooler. If living in super cold climate, i get it. But for the most part. Just a big cooler, separated from all engine coolant in my opinion, should be sufficient to cool. Just add an inline thermostat and until the tranny reaches your desired temp. It won't run through the cooler. That's better than having it run through the radiator in my opinion because then you run the risk of cross-contamination fluids as the vehicle ages.
On the 3.6 it is also isolated from engine coolant, and also sits in front of the radiator.
It is dependent upon airflow.
 
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CorDog009

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Did you happen to notice any drop in Engine oil Temp. and Transmission fluid Temp. with the 190* degree thermostat?
I assume the running stabilized engine coolant Temp. was reduced?
Edit: any problems with weird codes etc?

I haven't driven it yet, probably will drive it to work tomorrow. Just idling, the coolant temp appears to be a good 10* or more cooler. Like stated above, tranny cooler is separate from the radiator. I have a trans temp gauge with the sending unit in the pan, didn't feel like splicing into the cooler supply line, and a small electric fan on the cooler. No codes or anything yet, it probably has about an hour of idle time and some slight revving, so good so far. I don't have any way to measure engine oil temp, but I assume it would be a few degrees cooler.
 

Different Drummer

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I haven't driven it yet, probably will drive it to work tomorrow. Just idling, the coolant temp appears to be a good 10* or more cooler. Like stated above, tranny cooler is separate from the radiator. I have a trans temp gauge with the sending unit in the pan, didn't feel like splicing into the cooler supply line, and a small electric fan on the cooler. No codes or anything yet, it probably has about an hour of idle time and some slight revving, so good so far. I don't have any way to measure engine oil temp, but I assume it would be a few degrees cooler.
Thanks for the Info. I just realized that your truck is a 2005. Most likely there are differences that exist between the various fluid cooling systems through the years. I need to get in the habit of looking at the member information box when replying. I hope I can get the years of service from my truck that yours has provided.
 
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CorDog009

CorDog009

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Thanks for the Info. I just realized that your truck is a 2005. Most likely there are differences that exist between the various fluid cooling systems through the years. I need to get in the habit of looking at the member information box when replying. I hope I can get the years of service from my truck that yours has provided.

No problem. Mine had sat for a couple years while I was overseas working, and I've had a couple Mustangs that I've used for a few years as daily drivers, so it's helped to stretch the life of the truck out. It still has 173k miles on it, but has held up decently so far besides the usual wear and tear items. Power steering rack is leaking and I have a new one at home, just haven't felt like doing it just yet. Overall no complaints besides gas mileage lol.
 
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