Engine overheats under load (up long grades) with 35” tires

[Dankincaid]

Going up long grades or even steep grades and a shorter distance engine overheats 235° and the idiot light turns on.

It also has 35 inch tires a factory radiator and factory gearing my question is is there a cure without changing gearing to a higher ratio like 411s or 456s or spending a ton of money on a custom radiator?

 

[Anybodyhome]

Can you provide some basics on your JK?
Year, model, engine, gear, tire size, etc.?

 

[Dankincaid]

2014 JK 3.6 automatic transmission 6 inch lift 35 inch tires not sure of the gear ratio but it’s factory

 

[JeepJeezy]

Have you made sure your speedometer is correct? If your speedometer says 55 that you're actually doing 55? Your speedometer helps control shift points. If you have low gears like 3.21, the transmission will hold a gear longer, this will cause your coolant temperature to rise too.

 

[Dankincaid]

Have you made sure your speedometer is correct? If your speedometer says 55 that you're actually doing 55? Your speedometer helps control shift points. If you have low gears like 3.21, the transmission will hold a gear longer, this will cause your coolant temperature to rise too.

Yes I have a computer that modifies speed for oversized tires

 

[Lxxtsy]

When was the last time the coolant was flushed?

 

[Dankincaid]

When was the last time the coolant was flushed?

One month ago

 

[Danarch]

Did the problem start after the flush? If so you may have air trapped in the system. Did you change the themostate?

 

[Anybodyhome]

Did the problem start after the flush? If so you may have air trapped in the system. Did you change the themostate?

Good point...

But I also feel like the lift, tire size and gearing may be a combination that won't fix itself. Enter your VIN on this site and get a copy of the build sheet for your JKU. If you're running a 3.21 rear end with that lift and tire size, I can't say I'm surprised it's running warm.

 

[Mike AM]

My overheating issue was the air bubble. Once that was solved both the engine and transmission run cooler! I had a new radiator installed due to a leak and the mechanic did not get all of the air out!!

 

[K9TFURY]

Going up long grades or even steep grades and a shorter distance engine overheats 235° and the idiot light turns on.

It also has 35 inch tires a factory radiator and factory gearing my question is is there a cure without changing gearing to a higher ratio like 411s or 456s or spending a ton of money on a custom radiator?

One possibility is cool air intake, or making sure you have adjusted the tire size with like a TD2 or any kind of programmer

 

[Dankincaid]

Did the problem start after the flush? If so you may have air trapped in the system. Did you change the themostate?

It’s not the coolant, radiator, T-stat or coolant sensor. All have been replaced

One possibility is cool air intake, or making sure you have adjusted the tire size with like a TD2 or any kind of programmer

The tire size was handled with my programmer thank you

 

[BLACKJKU]

It’s not the coolant, radiator, T-stat or coolant sensor. All have been replaced

The tire size was handled with my programmer thank you

Did you burp all the air out after replacing the coolant?

You can find out what gears you have by entering your VIN number. Click on the link below.

Equipment Listing

 

[Dankincaid]

The factory gear ratio is 3.73

 

[Dankincaid]

Did you burp all the air out after replacing the coolant?

You can find out what gears you have by entering your VIN number. Click on the link below.

Equipment Listing

Thanks

 

[Dankincaid]

Thanks

No air in cooling sys

 

[BLACKJKU]

Is you cooling fan working?

Does it overheat if the A/C isn't on?

 

[Anybodyhome]

Is you cooling fan working?

If everything else checks out, this is about the last possibility out there.

 

[BLACKJKU]

I'm pretty sure that when the A/C is on the cooling fan goes into high speed. So the best way to check it would be with the A/C off to see if it overheats.