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Engine Coolant Temp Sensor Options

Discussion in 'Minivans · Pacifica' started by TaxiGirl, Apr 20, 2017.

  1. TaxiGirl

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    Hello, guess who?

    while looking at Carid at options for maintaining engine cooling i am seeing some switches that i do not see looking at mopar parts.
    I have never replaced the ECT but there are also cycling switches or other switches to take control of the engine fan . I do want more control of the cooling since the fan cicuit components are unreliable, etc tipm ect tstat the whole 9 yards and inconsistent.
    Are these options something that i can use on my 2011 dodge grand caravan and will these things work on my van?

    https://www.carid.com/2011-dodge-grand-caravan--engine-cooling-parts/
    Yesterday, i idled at airport off and on all day, and cooling fan came on high like it was supposed to and tstat opened and engines maintained below 212. But, last night when it was in the 70's. driving around downtown with ac on, engine started overheating reaching almost 230. I cycle through the vehicle info diagnostics and i see oil psi initially at 199 and high oil temp.. and very erratic readings of pressure and water temp.
    all i did was turn off the ac and and it straightened out after about 15 minutes. Then i turn ac on and temp is once again maintained under like 204 degrees. This issue is driving me nuts because it only happens when i pick up a passenger. Not only is it embarrassing to have to ask if i can turn off the ac in case my engine overheats but it makes no sense when it decides to act up. If i can strain the system at idling and it maintain correct temp, why in the world when i give it optimal conditions does it want to act up. please please please
     
    #1 TaxiGirl, Apr 20, 2017
    Last edited: Apr 20, 2017
  2. TaxiGirl

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    i Found the ECT. but how does one get to it.? Any tips on how to actually access the ECT and removing it?
     
  3. Doug D

    Doug D Virginia Gentleman

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    What engine? 3.6L? 3.8L?
     
  4. TaxiGirl

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    Never mind got it replaced it was a pain in the rear but not when i start vehicle enven with temp down to 120 when i turn ac on the ho speed fan comes on. it remains to be seen if the coolant temp sensor made any difference. Ever day it is something new
     
  5. TaxiGirl

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    OK IT DID NOT WORK AND HERE IS WHAT I FOUND

    I have power from J19 and on the hot side of K11 when it is supposed to be there. I checked and found that the LOW SPEED SIGNAL IS at 4.9 v on both sides of the coil on K11. the LOW SPEED FAN is not coming on. The high speed fan comes on and tries to cool off the engine but the low speed fan is supposed to keep it cooled off. Since I am getting the signal to turn on the low speed and the fan is staying off, until the high speed comes on and there is only 1 connection to the fan motor, what would prevent the low speed of the radiator fan from coming on? Now, when I was using the thermistor that is on the Murray fan, the high speed fan would not operate.. So, I replaced it with the other thermistor that I had from the OEM fan and now the high speed fan works. It is overheating when I am driving slow and not necessarily at idle because the high speed comes on and cools it down. I am real confused and I need the low speed to work for the radiator fan all of time. Is the fan itself bad.?
     
  6. TaxiGirl

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    Hi Doug same engine 2011 Dodge Grand Caravan 3.6

    I replaced the engine coolant temp sensor but it did not fix the problem and just now I did the below>

    OK IT DID NOT WORK AND HERE IS WHAT I FOUND

    I have power from J19 and on the hot side of K11 when it is supposed to be there. I checked and found that the LOW SPEED SIGNAL IS at 4.9 v on both sides of the coil on K11. the LOW SPEED FAN is not coming on. The high speed fan comes on and tries to cool off the engine but the low speed fan is supposed to keep it cooled off. Since I am getting the signal to turn on the low speed and the fan is staying off, until the high speed comes on and there is only 1 connection to the fan motor, what would prevent the low speed of the radiator fan from coming on? Now, when I was using the thermistor that is on the Murray fan, the high speed fan would not operate.. So, I replaced it with the other thermistor that I had from the OEM fan and now the high speed fan works. It is overheating when I am driving slow and not necessarily at idle because the high speed comes on and cools it down. I am real confused and I need the low speed to work for the radiator fan all of time. Is the fan itself bad.?
     
  7. TaxiGirl

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    I found this post by Allan from an earliar issue I had with the radiator fan. I am pasting it here because i have a question about something that he said.
    Me,. I KNOW THE HIGH SPEED FAN RELAY IS BEHIND DRIVERS SIDE HEADLIGHT BUT, I THOUGHT THE LOW SPEED FAN RELAY WAS K11 INSIDE THE TIPM. '


    ALLAN SAID///Here is a link that shows the electrical schematic for the radiator fan motor. There is a radiator fan motor low speed relay and a radiator fan motor high speed relay and both are located in the TIPM (totally integrated power module). Switch the high speed relay and put it into the location for the low speed relay and test to see if the fan runs in low speed. If it does then you know the relay is good.

    Notice that the power load for the low speed fan motor passes through a resistor. This reduces voltage and allows the fan to run at low speed. The high speed fan relay bypasses the resistor and provides full voltage to the radiator fan motor for high speed operation.

    IF BOTH RELAYS ARE IN THE TIPM WHICH ONES ARE THEY AND WHAT IS THE RELAY THAT I KEEP REPLACING BEHIND THE HEADLIGHT?
     
  8. AllanC

    AllanC Well-Known Member

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    While engine was at idle mode and vehicle stopped, was A C system engaged and operating?

    No gasoline engine in a minivan will have 199 psi oil pressure at idle. What is the reading when you say high oil temperature?

    If an engine does not overheat while at idle but overheats when driving that points to a restricted radiator / partially plugged internal tubes. At slower engine speeds the radiator is able to reject the heat from the coolant. But when driving on the highway you are burning fuel at a higher rate which creates more heat, the water pump is pushing more coolant through the radiator. If it is partially plugged then it cannot reject the higher heat content and thus engine temperature will increase.

    At highway speeds there is more than ample air flow through the A C condenser and radiator to provide cooling. You could remove the radiator fan as it is not needed when driving at highway speeds. So the radiator fan is not causing the overheating at highway speeds.
    Turning off the A C while on the highway reduces the heat load on the radiator and a compromised radiator can just barely keep the engine in the proper operating temperature range.

    It is possible that the water pump could be a cause of the overheating. If the impeller on the pump is plastic, it could be damaged and not providing the flow rate necessary to keep the engine cool at highway speeds. Maybe others can comment and indicate if the water pump impeller is plastic and could be damaged or broken and causing the overheating issue.
     
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  9. Doug D

    Doug D Virginia Gentleman

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    Agree with Allan. If the engine temperature is normal while idling, but overheats while driving it certainly points to a partially clogged or restricted radiator. In addition inspect the radiator for any missing fins. They are critical for transferring the heat.

    At speeds less than 35 mph there is not enough ram air effect to cool the radiator so the fan should come on at the appropriate temperature reading. Above 35 mph there is sufficient air flow that the fan is not needed. If the temperature is above normal at speeds above 35 mph (where the fan may not be on) then this indicates the radiator is clogged/restricted (probably due to scaling) and cannot effectively transfer the heat.

    I had similar symptoms with an Acclaim I had. At idle it would be "normal" and at highway speeds the temperature gauge would creep up to 3/4 or so on the gauge (not quite into the red hot zone). Replacing the radiator solved the issue.
     
  10. TaxiGirl

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    Water pump was replaced a couple of months ago. And, I cannot say that it overheats with any kind of consistency. I can idle with ac running for an hour or more in the heat of the day and temp is maintained at 210. The Oil temp reading may have been the digital readout settling down to a number. idk i have never seen that happening but the oil temp was high as well, i cannot remember what it was. I just changed the oil and filter 1400 miles ago. On the highway, the temp is maintained around 210. It is when I am driving slow and the ac is on like driving though town and stopping at red lights or in traffic stop and go that it starts to over heat. The low speed radiator fan is supposed to be on as soon as you start the vehicle per the schematic. 12 V is reduced through the thermistor to slow down the fan. But, I am wondering how could the high speed be working when it is supposed when the low speed does not work at all? The way it appears to me is that when the low speed is supposed to come on, that I should have 12volts supplied to 1 side of the thermistor and the ground would be already there on the other side to make the fan come on for low speed, I am just saying in theory, I am not looking at the schematic. But, if the fan should be on the whole time when engine is running, all that would take to make that happen is for the control circuit to turn off the low speed signal I think the low speed signal is staying on all the time. Am I wrong about it looking like it should be on the whole time the engine is running, Is that the way it is wired or designed?
     
    #10 TaxiGirl, Apr 21, 2017
    Last edited: Apr 21, 2017
  11. TaxiGirl

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    If I use distilled water only mixed with antifreeze and have never seen any evidence of scale, how could it be clogged?
     
  12. Doug D

    Doug D Virginia Gentleman

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    The additives in the antifreeze can deteriorate over time which can eventually lead to scaling. It doesn't actually have to clog up the rods in the radiator, but if enough scale is there it can inhibit proper heat transfer.
     
  13. TaxiGirl

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    I replace the antifreeze or for some reason I have drain the radiator every 2 or 3 months, so the antifreeze really never has a chance to get old.
     
  14. TaxiGirl

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    I am listening to you, short of replacing the radiator can it be tested?
    Also regarding the oil temp. i have been using 1 quart of marvel mystery oil to 5 qts 5 w20 or 5w30 for the last 6 or 8 months. maybe the viscosity is too thin. what affect could this have ?
     
  15. TaxiGirl

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    OMG my oil temp right now driving is 183 degrees
     
  16. Doug D

    Doug D Virginia Gentleman

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    I have no idea if that is too high or too low or normal? What oil temperatures have you observed in the past? Considering the optimal engine temperature is around 200 F this sounds like it may be okay.
     
  17. AllanC

    AllanC Well-Known Member

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    This points to an extreme heat load generated through the transmission. Stop and go driving with lots of upshifting and downshifting of gear ratios in the transmission will generate a lot of heat. The 4Xte and 6Xte transaxle shifting logic tended to allow more slippage and thus generated more heat on the transmission. This gets passed along to the engine cooling system.

    I remember in a previous post that it appeared the automatic transaxle was overfilled. Too much fluid in the transmission can cause excessive heat generation. Did you get the fluid level set correctly?

    The radiator fan speed selection is controlled by the TIPM and the PCM. If engine coolant temperature is above a certain threshold and / or the A C compressor is engaged, the PCM sends a signal to the TIPM for cooling fan operation. The TIPM determines criteria and then engages either the low speed fan relay or the high speed fan relay. Are you getting a CHECK ENGINE lamp symbol along with diagnostic codes P0480 and P0481?

    Here is a schematic of the radiator fan control circuit and load circuit. There is only 1 radiator fan with 2 control inputs. The TIPM controls both the low speed and high speed through separate relays. When the low speed fan relay is engaged 12 volts is passed through a resistor circuit that drops the voltage to the fan motor. The motor runs at reduced speed.

    Radiator Fan Circuit Control.GIF

    When more air flow is needed through the A C condenser and radiator for greater cooling the TIPM engages the high speed relay. A full 12 volts is applied to the fan motor. At this point it does not matter if the low speed relay remains engaged or not. The 12 volts is higher voltage and overshadows so to speak the lower voltage so the fan motor immediately runs at its maximum designed speed.
     
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  18. AllanC

    AllanC Well-Known Member

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    I really don't think the additive is causing a problem of overheating or excessive wear due to viscosity. The only accurate and scientific way to determine engine wear is to send a sample of the engine oil at drain time to a specialized lab. Excessive bearing wear (caused by too thin / low viscosity oil) will appear as excessive traces of bearing metal in the oil.

    You are within the safe limits of engine oil temperature. In fact oil temperature should be higher so as to evaporate moisture and other liquid condensate contaminants from the oil. I would typically expect engine oil temperature to be slightly below coolant temperature.
     
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  19. TaxiGirl

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    no check engine light and when i stopped a little ago i pulled out the dipstick to see if it felt hot and it did not seem that hot. but now i have been monitoring the oil temp and psi. when driving above 60 oil temp is 199 and psi is 37 psi. when stop at redlight oil temp stays same and oil psi drops to 20psi. i am on my way to buy oiil. but, what else should i do
     
  20. TaxiGirl

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    does a radiator psi test check for bsf radiator or just for leaks. there are too many unknows right now i do not know what to do
     

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