Not Jeep But is Chrysler... Overcooling

DadOSix

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Swag -

Can you scanner do real time data?

Maybe have a look at all the other temp related items. Iat / map

Also - fuel trims long and short.

If there is a fault in these other temp sensors, intake air temp - it MIGHT result in what you are seeing.
 

kejobe

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Swag -

Can you scanner do real time data?

Maybe have a look at all the other temp related items. Iat / map

Also - fuel trims long and short.

If there is a fault in these other temp sensors, intake air temp - it MIGHT result in what you are seeing.
Yes, it can do real time. Honestly though, I'm tired of messing with it. 195* is good enough.

I'm just baffled as to why.
 

Michael Wolfe

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You've just solved global warming. Just hook your cooling system up to the planet.

So, in theory, the T'stat stays shut until it reaches opening temperature. Normally, you see this as the temp rises and then drops, as a slug of cold water from the radiator enters the engine. the temp stabilizes as the thermostat and temperature of water exiting the radiator find a happy median. If you have excessively cold water exiting the radiator, then by the time it flows through the engine and gets ready to exit by the thermostat, it cools the engine too much, and the thermostat throttles down the flow until it warms up. If it never gets up to temperature, then the thermostat isn't closing properly, or the coolant is finding some other path through the radiator.
Are you confident that the temperature sensor is accurate? Have you verified it by some other means? Does the radiator get hot?
As far as the A/C goes, it's normal for it to engage at any defrost setting, as it also de-humidifies the air, making it good to defog windows.
Does the heat not work as well? I would also check for proper operation of the fan clutch.
 

kejobe

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You've just solved global warming. Just hook your cooling system up to the planet.

So, in theory, the T'stat stays shut until it reaches opening temperature. Normally, you see this as the temp rises and then drops, as a slug of cold water from the radiator enters the engine. the temp stabilizes as the thermostat and temperature of water exiting the radiator find a happy median. If you have excessively cold water exiting the radiator, then by the time it flows through the engine and gets ready to exit by the thermostat, it cools the engine too much, and the thermostat throttles down the flow until it warms up. If it never gets up to temperature, then the thermostat isn't closing properly, or the coolant is finding some other path through the radiator.
Are you confident that the temperature sensor is accurate? Have you verified it by some other means? Does the radiator get hot?
As far as the A/C goes, it's normal for it to engage at any defrost setting, as it also de-humidifies the air, making it good to defog windows.
Does the heat not work as well? I would also check for proper operation of the fan clutch.
I'm on the 3rd thermostat since this started. Checked sensor with OBD scanner. Was reading correct. Figure what the h3ll and changed sensor anyway. Still got the same readings.

Before this the needle would go just above the center line and settle just below as the hot and cold coolant mixed. This was at the 200* mark. Now it settles at 195*. All this verified with the scanner.

Everything appears to be working properly, it just decided to drop its operating temp a few degrees.

Heat still works good as it always has.
 

Ksat

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Sounds like you're splitting hairs here. Not seeing a real problem in what you presented. Also, as already stated here, the electric rad/condenser fan (on KJ's anyway) is meant to always be on when the selector is in the defrost setting.
 

Michael Wolfe

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Since everything seems normal, perhaps something had been restricting the cooling system somewhere, and either dissolved or otherwise moved along. I assume it's been the same in the non 12F degree days (I'm in Erie, PA). My CRD is a bit lower than normal lately.
 

CRD28

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Not KJ related but still looking for opinions/options. Please move if there's a better place for this.

2008 Ram 1500 SLT 5.7L 4WD

Past week the truck has been overcooling. Thought thermostat was stuck open so replaced it on Saturday. Same issue. Replaced the temp sensor today even though my scanner was giving correct readout of the temp. Still overcooling/not getting to full temp, or taking A LOT longer than normal to reach full temp.

I did notice that the AC fan is running constantly with the selector in defrost. Switch to vent and it will shut off. Turn blower fan/system to off and fan will stop. Problem is I always keep the selector in the defrost/foot position.

This whole time the temp selector is in the hot position. AC button is off.

With this said, I was thinking the TIPM connections could be corroded causing the fan to constantly run. With it running, I'm thinking it's pulling cold air in across the motor and cooling the motor itself. I cleaned them with contact cleaner and put some dielectric grease on. Issue continues.

I'm thinking the TIPM is bad somewhere or something is going on with it.

Anything I may be missing? I unplugged the AC fan for now. Haven't ran truck yet to see if it helps.
Personally and I’m not a qualified mechanic, quality motor vehicle parts stores Keeper
I think possibly three options
Head
Cylinder cores in the head for the water ways .Sludge
Radiator cores ( Sludge
Collapsed water pipe
Unfortunately could be anything that unfortunately you need to do a eliminate series.
Best of luck
 

Michael Wolfe

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Personally and I’m not a qualified mechanic, quality motor vehicle parts stores Keeper
I think possibly three options
Head
Cylinder cores in the head for the water ways .Sludge
Radiator cores ( Sludge
Collapsed water pipe
Unfortunately could be anything that unfortunately you need to do a eliminate series.
Best of luck
I believe those would be contributors to overHEATing, but the issue appears to be running cold.
 

gayle.woods

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Almost every modern vehicle uses the AC compressor (winter & summer) in defrost and defrost/floor mode to remove unwanted humidity from the inside air so the windows don't fog up. When the compressor is commanded on it also commands the fan to run to pull a sufficient amount of air across the condenser which in-turn depending on ambient temperature may cause the coolant temp to fall a few degrees. Since the temp gauge located in the instrument cluster is a relative reading based on voltage it is possible for it to read different from the scan tool.
 
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Johnny O

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Since everything seems normal, perhaps something had been restricting the cooling system somewhere, and either dissolved or otherwise moved along. I assume it's been the same in the non 12F degree days (I'm in Erie, PA). My CRD is a bit lower than normal lately.
Another Erieite!?!? What are the odds?
 

kejobe

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I know it's not detrimental, but it was/is just buggin me. At this point, I don't really care. Still have heat and is within "range" of operating temp.

Thank you to all who has helped.
 

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