anyone makes a lower temp thermostat ?

Maverick909

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LOL, running no thermostat is a terrible idea, even in warmer climates. You’re keeping the oil from coming up to temperature for significantly longer, which speeds up the wear process and could lead to early failures.
300K on my motor before i opted to do a swap out for more power. also had a k5 with 330K when it sold... no stat in that truck either..... not to worried about a possibility of pre-mature wear. motors will last if you take care of their maintenance, fluid levels, and drive respectfully. i plan on putting 250K or more on the v-6 in my jeep.
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Demonic

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I'm still trying to follow the logic here. The thermostat doesn't determine the operating temp of the car. It determines at one point during the warm up of the engine the cooling switches from closed loop (no radiator) to open loop (through the radiator). A lower temp thermostat would just make the engine take longer to reach operating temp. Once it's open, it doesn't affect the cooling.
 

Fire Burns

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Some of the naysayers here are missing the OP's point. He's looking for a cooler thermostat for a variety of reasons. He's not saying he's an FCA Jeep engineer, but neither are any of the nanny's here so far as I can tell. In a above posts, both myself and @m3reno gave a couple of legit real-world examples where a cooler thermostat showed real benefits. So who's to say without any empirical evidence one way or the other if this is worth doing.

As I said before, it does no good for the OP to NOT try this mod and then upon reporting back his findings, perhaps we all learn something here in our community.
 
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Demonic

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Sure, just as well as he could change his left rear tire and report back on his engine temps. Even if they changed it doesn't mean the tire was the causative agent. A thermostat in a car is not like a thermostat in a house. It doesn't set the running temperature of the engine. It sets the engine warm-up point.
 
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garkoi

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I went out to look for a thermostat today the oem one has the thermostat fixed to the housing and those made for the grand cherokee that have the thermostat held in by a retaining clip can be swapped and will fit but doesnt have the temp sensor so i wont be able to monitor the results and that will keep me from posting results and monitoring it so im going to keep looking for one.



I'm still trying to follow the logic here. The thermostat doesn't determine the operating temp of the car. It determines at one point during the warm up of the engine the cooling switches from closed loop (no radiator) to open loop (through the radiator). A lower temp thermostat would just make the engine take longer to reach operating temp. Once it's open, it doesn't affect the cooling.

you are right, the thermostat doesnt determine the operating temp, however it closes when the temps are below what they are rated at, so the oem rated at 203 will be closed and stay closed till it reaches 203 then it will open and allow cool coolant in from the radiator the temps will drop at say 190 then it will close, open and close multiple times, the radiator, the fan and the thermostat all help maintain "minimum" operating temps, if you are pushing the car hard beyond the capacity of the radiator/fan capacity the temps will climb no matter what u do however hit 230 and the fans goes into high speed pulling more airflow and cooling your system at max capacity, depending on the load it might lower ur coolant temps or it might continue climb.

however if it gets too hot, you pull over and wait, the temps will go down and eventually it will reach 190 thats when the thermostat will close again so the engine stays within the range determined by the thermostat.

the 3.6 Has a 203 thermostat it should be able to maintain that temp at idle since higher you get open loop and it pulls the temp down till it reaches the closing threshold and then cycle maintaining that temp

a lower thermostat (180) will reconfigure the designed operating temp it will open at 180 instead of 203 and you get open loop sooner, it might help, if with a 203 thermostat i start going up a steep grade road starting at 203 and end up with 230 and the high speed fan kicks in, the 180 thermostat gets me started at 180 and i may not hit 230 and the high speed fan might never kick in.

again this is all assuming the capacity of the radiator and the fan speeds can handle keeping the temps at 180, the jt has 850watt fans we have the 650watt fans same radiator, but while towing they will push their temps higher, the faster fans will pull more air thus they have more cooling capacity, if we install the 850watt fans we will be able to keep the temps closer to 203 than with 650watt fans, we cant reach a temp lower than 203 because thats what the thermostat is doing, it prevents us from going below a set value.

if you temps are running around the temp of the thermostats rating AT IDLE then your system is working fine, however id like more headroom by lowering the operating temp from 203 at idle to 180 then i doubt you will get any issues it might help it might not.
 
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garkoi

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Sure, just as well as he could change his left rear tire and report back on his engine temps. Even if they changed it doesn't mean the tire was the causative agent. A thermostat in a car is not like a thermostat in a house. It doesn't set the running temperature of the engine. It sets the engine warm-up point.
A thermostat is a component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint. This is the definition of a thermostat, In a car, house or submarine it works the same way turn a system on off to regulate a set temp, a person using his car in sub zero temp will have his thermostat shut most of the time the car is running, take the same car to 140+ weather the thermostat will be open most of the time, the thermostat help keep the engine at temps set by the thermostat itself, if you have the cooling capacity (radaitor/fan) thats why the JT has bigger fans with the tow package cause while towing the temps were far from 203 so bigger fan kept it there.
 

Demonic

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Ok, but it would also mean that you don't mind it potentially messing with you AFR's too. An engine doesn't run as efficiently at lower temps and the ECU typically richens the mixture at lower temps to compensate. I don't know enough about the jeep ECU to be certain.
 

CoolTech

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From cold start, a modern ECU will be in warm-up mode until a minimum water temp is achieved - typically well below the thermostat setting (blame emissions programming). At this point, the ECU exits warm-up and will be in closed-loop mode using its O2 sensors to deliver an ideal 14.7:1. In most vehicles, this mixture (while in closed-loop) will never change. (O2 sensors are only accurate to say you are above or below 14.7:1... so you can't just decide to target another A/F ratio.) If temps go to extreme, the ECU will back off of timing - but leaves A/F's alone.

Under heavier throttle, the engine will need a richer mixture and the ECU will exit closed-loop mode (reliance upon O2 sensors) and will go to open-loop. In open-loop, the ECU is running off of pre-programmed tables..... remember that the ECU can't just target another (richer) A/F because the O2 sensors on only reliable at 14.7:1.

A 180F thermostat would most likely result in the Jeep running at 180F in cooler weather. I wouldn't expect the electronics to complain. But, as op has noticed, in extreme temps, the Jeep is already at max capacity for cooling so max temps will not be any different... maybe delayed for seconds, but not minutes. If the op's aspiration is to have 180F op temps in cooler weather, he will accomplish that. The benefit of having achieved that? Not sure.
 

Mrchams

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Your "taste" is irrelevant in modern vehicles, changing the thermostat temps will send the vehicles computer (the only opinion that matters) into a fit, good luck with all those check engine lights...
Mine runs as high as 116 deg c (240 f) which is way too high.
The oil temps get over 108 deg c (226 f)
Again way too high.

If there is an alternative thermostat I’m all for it.
 

SavannahAL

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Garkoi - I'm with you. I bought my 2018 JL Base in the summer of 2018 and it overheats. I haven't hit 244 but I've reached 238 (at least what the digital temp is telling me) with boiling in the coolant reservoir. I bought mine with the intention of towing an A-Liner to West Virginia but I never tow anything with it for fear of being on the side of the road. Mine runs 205-238 routinely.

I'm still glad I bought mine, it is my retirement gift to myself. If you find a successful fix please let me know.
AL
 
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garkoi

garkoi

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Mine runs as high as 116 deg c (240 f) which is way too high.
The oil temps get over 108 deg c (226 f)
Again way too high.

If there is an alternative thermostat I’m all for it.
How hard are you pushing your jeep to see those temps ? I see your from Australia so are you at max payload, roof rack, towing ? But a lower thermostat won't help you here since ur waaay past its open set point and your temps are going up cause your thermal load is more than your cooling capacity in whatever situation you saw those temps, i recommend
1. JT 850w fan.
2. a bypass switch, flip it on and it goes into high speed bypassing factory fan mapping.
3. JT grill inserts, i dont know how much it will effect cooling but every bit helps.
4. Removing the heat shield under the hood.
5. Converting the fake hood vents into real vents.

As to a lower thermostat i still didnt find any, i dont think i will find any since i looked into all the cars that share the same part number and none have a lower thermostat available, so option 2 which will most likely fix the issue with heat under load, is to keep the temp at oem minimum running temp by upgrading the cooling system.

Garkoi - I'm with you. I bought my 2018 JL Base in the summer of 2018 and it overheats. I haven't hit 244 but I've reached 238 (at least what the digital temp is telling me) with boiling in the coolant reservoir. I bought mine with the intention of towing an A-Liner to West Virginia but I never tow anything with it for fear of being on the side of the road. Mine runs 205-238 routinely.

I'm still glad I bought mine, it is my retirement gift to myself. If you find a successful fix please let me know.
AL
The same upgrades above should apply to any jl, do you have the tow package ? I know the tow package comes with a 240amp alternator and 850w fan on the gladiator, i assume its the same on the jl not sure about the fans. So if you bought the tow package i would check the fan if it says 600w or 850w. Its a white sticker.

44715EC6-7D26-4015-88F8-B8CF1088A317.jpeg
 

mwilk012

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How hard are you pushing your jeep to see those temps ? I see your from Australia so are you at max payload, roof rack, towing ? But a lower thermostat won't help you here since ur waaay past its open set point and your temps are going up cause your thermal load is more than your cooling capacity in whatever situation you saw those temps, i recommend
1. JT 850w fan.
2. a bypass switch, flip it on and it goes into high speed bypassing factory fan mapping.
3. JT grill inserts, i dont know how much it will effect cooling but every bit helps.
4. Removing the heat shield under the hood.
5. Converting the fake hood vents into real vents.

As to a lower thermostat i still didnt find any, i dont think i will find any since i looked into all the cars that share the same part number and none have a lower thermostat available, so option 2 which will most likely fix the issue with heat under load, is to keep the temp at oem minimum running temp by upgrading the cooling system.


The same upgrades above should apply to any jl, do you have the tow package ? I know the tow package comes with a 240amp alternator and 850w fan on the gladiator, i assume its the same on the jl not sure about the fans. So if you bought the tow package i would check the fan if it says 600w or 850w. Its a white sticker.

44715EC6-7D26-4015-88F8-B8CF1088A317.jpeg
The gladiator with tow package has its own fan, the JL was not built for towing and does not have additional cooling options.
 

zrickety

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I am not an engineer either, but has anyone considered the oil? 0w-whatever is very thin. Most vehicles in hot climates recommend 10w-30 or better. My turbo cars do much better with it than 5w or 0w options.
 
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