2021 Sahara Overheating on freeway

[SalmonJeeper]

Hi ,

Looking for advise on this issue, my Sahara is overheating when driving on freeway on up hills that demand the rpms to stay on 2k to 3.5K rpms (not to high)
by overheating I mean, slowly going up from the normal temperature of 85 to 90C, reaching up to 117C, at the point of 114C the digital meter begins to go up.
I think this could not be normal behavior since I am not even towing, so is getting hard time to move itself.
some extra information is the outside temperature is over 40C. Driving under these conditions in the city won't cause any overheat, it just stay around 90C. the problem is on the Freeway

Already replaced the antifreeze, using Prestone purple recommended for Jeeps, this also to ensure the correct level, no trap air in the lines.
also the motor oil is new, Castrol 5w-30 Advanced Full Synthetic. I think the next step could be to replace the thermostat but is kind expensive, is only sold including the housing and is around $ 170.
Besides, my Sahara does not have the extra reservoir for coolant as my 18 JL Sport S does, maybe is needed on extreme hot weather.

Any advise is highly appreciated, searched for any other overheating case but can't find any similar

Thank you

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[Old Dogger]

You didn't tell us how many miles on it, and what engine you have. Since you only have one overflow bottle, then you have the 3.6. The 2.0 has two, because of the turbo engine.
O.K., that is 242.6 degrees. That is a bit on the high side. There is many things that it could be. But you should only be using MOPAR OAT 50/50 mix Antifreeze, in your engine. I suggest that you flush the cooling system, install a new MOPAR thermostat, then refill with the correct antifreeze and bleed the air out of engine cooling system. Flush the external radiator core, with a garden hose. Then try it out. Hopefully, you still have your Air Dam on your Wrangler.

 

[Remorseless]

You didn't tell us how many miles on it, and what engine you have. Since you only have one overflow bottle, then you have the 3.6. The 2.0 has two, because of the turbo engine.
O.K., that is 242.6 degrees. That is a bit on the high side. There is many things that it could be. But you should only be using MOPAR OAT 50/50 mix Antifreeze, in your engine. I suggest that you flush the cooling system, install a new MOPAR thermostat, then refill with the correct antifreeze and bleed the air out of engine cooling system. Flush the external radiator core, with a garden hose. Then try it out. Hopefully, you still have your Air Dam on your Wrangler.

His signature says it's the 2.0, could be an eTorque 2.0 though, that I'm not sure of.

Hi ,

Looking for advise on this issue, my Sahara is overheating when driving on freeway on up hills that demand the rpms to stay on 2k to 3.5K rpms (not to high)
by overheating I mean, slowly going up from the normal temperature of 85 to 90C, reaching up to 117C, at the point of 114C the digital meter begins to go up.
I think this could not be normal behavior since I am not even towing, so is getting hard time to move itself.
some extra information is the outside temperature is over 40C. Driving under these conditions in the city won't cause any overheat, it just stay around 90C. the problem is on the Freeway

Already replaced the antifreeze, using Prestone purple recommended for Jeeps, this also to ensure the correct level, no trap air in the lines.
also the motor oil is new, Castrol 5w-30 Advanced Full Synthetic. I think the next step could be to replace the thermostat but is kind expensive, is only sold including the housing and is around $ 170.
Besides, my Sahara does not have the extra reservoir for coolant as my 18 JL Sport S does, maybe is needed on extreme hot weather.

Any advise is highly appreciated, searched for any other overheating case but can't find any similar

Thank you

Does it overheat around town or only on the freeway? You should have two coolant reservoirs on the 2.0 Turbo - one black one at the back of the engine bay, on the driver's side, and one clear one at the front. Are both full?

 

[AnnDee4444]

Just to confirm coolant reservoir locations:
5 & 6: Engine
8 & 9: Power Pack (48V battery for eTorque)
11/12: Intercooler & generator (BSG for eTorque)

 

[SalmonJeeper]

You didn't tell us how many miles on it, and what engine you have. Since you only have one overflow bottle, then you have the 3.6. The 2.0 has two, because of the turbo engine.
O.K., that is 242.6 degrees. That is a bit on the high side. There is many things that it could be. But you should only be using MOPAR OAT 50/50 mix Antifreeze, in your engine. I suggest that you flush the cooling system, install a new MOPAR thermostat, then refill with the correct antifreeze and bleed the air out of engine cooling system. Flush the external radiator core, with a garden hose. Then try it out. Hopefully, you still have your Air Dam on your Wrangler.

Thank you, appreciate your response, my Sahara is only 19K miles, is 2.0L turbo (did not mentioned because I though I posted my case in the 2.oL turbo forum)
This Sahara has 2 bottles, they are fully loaded with purple antifreeze but they were also with the mopar, same results.

What I was trying to explain is that the 2021 Sahara has 2 bottles/reservoirs while my 2018 JL Sport S has 3 bottles reservoirs. Hope someone knows why

Thank you

 

[SalmonJeeper]

His signature says it's the 2.0, could be an eTorque 2.0 though, that I'm not sure of.



Does it overheat around town or only on the freeway? You should have two coolant reservoirs on the 2.0 Turbo - one black one at the back of the engine bay, on the driver's side, and one clear one at the front. Are both full?

His signature says it's the 2.0, could be an eTorque 2.0 though, that I'm not sure of.



Does it overheat around town or only on the freeway? You should have two coolant reservoirs on the 2.0 Turbo - one black one at the back of the engine bay, on the driver's side, and one clear one at the front. Are both full?

Thank you for your reply

Only overheat on freeway not in town
it has 2 reservoirs, both fully loaded

What I was trying to explain is that the 2021 Sahara has 2 bottles/reservoirs while my 2018 JL Sport S has 3 bottles reservoirs. Hope someone knows why

Thank you

 

[SalmonJeeper]

Just to confirm coolant reservoir locations:
5 & 6: Engine
8 & 9: Power Pack (48V battery for eTorque)
11/12: Intercooler & generator (BSG for eTorque)

Thank you for your reply

The 2021 Sahara has 2 reservoirs, # 5 and # 12 while the 2018 JL Sport S 2.0L has 3 reservoirs #5,#12 and #9. Do you know what power pack means?

Thank you again

 

[AnnDee4444]

Thank you for your reply

The 2021 Sahara has 2 reservoirs, # 5 and # 12 while the 2018 JL Sport S 2.0L has 3 reservoirs #5,#12 and #9. Do you know what power pack means?

Thank you again

The "power pack" is the eTorque system's 48V battery cooling circuit. This also means that reservoir 12 is dedicated to the intercooler instead of being shared with the BSG (Belt Starter Generator).

If anything, a non eTorque JL like your 2021 should cool better than one with eTorque, since there are less heat exchangers/radiators to cool.

Are there any modifications that could block radiator flow? Winch/bumper guard/lights/etc.?

 

[Remorseless]

Thank you for your reply

Only overheat on freeway not in town
it has 2 reservoirs, both fully loaded

What I was trying to explain is that the 2021 Sahara has 2 bottles/reservoirs while my 2018 JL Sport S has 3 bottles reservoirs. Hope someone knows why

Thank you

What have the air temperatures been like when it's overheated? And is the radiator clean, like have you hosed out any dust or mud from it? Other than that, I would look around the engine bay to see if you can find any pink crust forming on any hoses or fittings to ensure there's not a leak or anything trying to form.

 

[SalmonJeeper]

The "power pack" is the eTorque system's 48V battery cooling circuit. This also means that reservoir 12 is dedicated to the intercooler instead of being shared with the BSG (Belt Starter Generator).

If anything, a non eTorque JL like your 2021 should cool better than one with eTorque, since there are less heat exchangers/radiators to cool.

Are there any modifications that could block radiator flow? Winch/bumper guard/lights/etc.?

No modifications to the front other than metal bumper (same in both Wranglers) with an 12" LED light but is not even close to the grill (OEM), the air flow is ok in my opinion

At this point I think I just need a 3 lines radiator to replace the OEM, this was a common practice in old cars where i live (hot summers with temps over 110F)

Thank you

 

[SalmonJeeper]

What have the air temperatures been like when it's overheated? And is the radiator clean, like have you hosed out any dust or mud from it? Other than that, I would look around the engine bay to see if you can find any pink crust forming on any hoses or fittings to ensure there's not a leak or anything trying to form.

The temp outside was from 110 to 120F
The radiator seems to be clean, free for good air flow

Thank you

 

[Remorseless]

The temp outside was from 110 to 120F
The radiator seems to be clean, free for good air flow

Thank you

What speeds do you run on the highway? The little turbo is hard to cool, might just be too much RPM for too long at too hot of an ambient temperature.

 

[SalmonJeeper]

What speeds do you run on the highway? The little turbo is hard to cool, might just be too much RPM for too long at too hot of an ambient temperature.

65 to 75 MPH, rpms are not higher than 3.5K
My Sahara has 35x12.5 R17 tires on it, Do you think could be the cause?

Thank you

 

[AnnDee4444]

65 to 75 MPH, rpms are not higher than 3.5K
My Sahara has 35x12.5 R17 tires on it, Do you think could be the cause?

Thank you

Someone will probably immediately disagree with me...

No, a larger tire size will actually have less rolling resistance and gearing isn't an issue because the transmission will be in a lower gear. However wheel offset and/or lift height can add to additional wind resistance.

 

[Remorseless]

65 to 75 MPH, rpms are not higher than 3.5K
My Sahara has 35x12.5 R17 tires on it, Do you think could be the cause?

Thank you

Not so much the tires, but basically it's extra heat load on the engine when the trans is in a lower gear and you're climbing. The turbo and extra fuel you're burning at 3,000 RPM will generate a lot of extra heat and with the JL already being kind of at the limit for cooling capacity, it gets hot.

So, you could go with deeper axle gearing so you could run in a higher transmission gear and lower RPM and thus lower heat generation, you could go with a smaller tire size to also allow a higher transmission gear and thus lower RPM and heat generation, you could drive slower to avoid prolonging the time at that higher RPM range, you could change out the grill inserts for Gladiator grill inserts to give the radiator as much extra airflow as you can, or some combination of these.

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