HELP - JKU Overheating and Transmission Hunting
03-25-2017, 02:44 PM
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HELP - JKU Overheating and Transmission Hunting
Looking for some help regarding my 2013 JKU 3.6L automatic with respect to overheating and transmission hunting.
Some background on my JK. I installed a 4" lift, runnning 35" tire, 3.73 gear set up, aftermarket aFe cold air intake, new spark plugs, smitybilt XRC front and rear-end and tire carrier (lots of weight) plus utilizing the Superchip Traildash 2. Recently replaced the rad cap and thermostat (195f). I live in Cabo San Lucas; basically at sea level.
Some background on my JK. I installed a 4" lift, runnning 35" tire, 3.73 gear set up, aftermarket aFe cold air intake, new spark plugs, smitybilt XRC front and rear-end and tire carrier (lots of weight) plus utilizing the Superchip Traildash 2. Recently replaced the rad cap and thermostat (195f). I live in Cabo San Lucas; basically at sea level.
Overheating symptoms - When I go for drives up the coast to Toto Santos this morning (this is has been on ongoing issue) the Jeep experiences cyclical overheating issues meaning the engine coolant goes from 200f to 230 back to 200f over a 3 minute cycle. The TFT average was 167f in town; low 157 the highway and high 170 (for all of 15-20 seconds) in town climbing a steep hill in Pedregal. ECT hit 230 numerous times and 234 twice until I turned on the AC to assist cooling down the ECT. Transmission flush about a year ago. The AIT temp high was 154f while outside engine compartment air temp was 75f.
Transmission Hunting - I think I know the answer (gear related) to this one but I want to double check. The transmission is not shifting properly meaning when shifting from 3rd to 4th or 4th to 5th, the RPMs are revving high while climbing a sligt incline. I either have to take the foot off the gas to allow it to shift or floor it to get it up to a higher speed and then it shifts. This happens in all gear ranges. No issues going down hill. The Superchip is set for 3.73 gears, actual tire height (34") and tire pressure, 35psi at the moment. Transmission temp does not seem to be an issue when the ECT rises to 230f.
thoughts? Looking for suggestions here in Cabo
Transmission Hunting - I think I know the answer (gear related) to this one but I want to double check. The transmission is not shifting properly meaning when shifting from 3rd to 4th or 4th to 5th, the RPMs are revving high while climbing a sligt incline. I either have to take the foot off the gas to allow it to shift or floor it to get it up to a higher speed and then it shifts. This happens in all gear ranges. No issues going down hill. The Superchip is set for 3.73 gears, actual tire height (34") and tire pressure, 35psi at the moment. Transmission temp does not seem to be an issue when the ECT rises to 230f.
thoughts? Looking for suggestions here in Cabo
03-25-2017, 09:12 PM
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03-26-2017, 05:41 AM
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When I went from 3.21 to 4.88 in my 2014 (35" tires), gear ratio set with an AEV ProCal, I started experiencing the same heat issues, ECT would get to 230-235. Never had a CEL or anything, but it still concerned me. Had the Jeep at a dealer for a solid 7 hours and they could find nothing wrong. I would open the windows, point the dash vents to the outside, and crank up the heater to keep it down.
It doesn't like to shift into 5th when accelerating to speed on the freeway but I'm thinking that might be because of my gear ratio.
I resolved some of the heat issues with a HyLine Offroad hood louver. I dropped 10-15 degrees after doing that.
It doesn't like to shift into 5th when accelerating to speed on the freeway but I'm thinking that might be because of my gear ratio.
I resolved some of the heat issues with a HyLine Offroad hood louver. I dropped 10-15 degrees after doing that.
03-26-2017, 06:28 AM
#5
JK Jedi
Looking for some help regarding my 2013 JKU 3.6L automatic with respect to overheating and transmission hunting.
Some background on my JK. I installed a 4" lift, runnning 35" tire, 3.73 gear set up, aftermarket aFe cold air intake, new spark plugs, smitybilt XRC front and rear-end and tire carrier (lots of weight) plus utilizing the Superchip Traildash 2. Recently replaced the rad cap and thermostat (195f). I live in Cabo San Lucas; basically at sea level.
Some background on my JK. I installed a 4" lift, runnning 35" tire, 3.73 gear set up, aftermarket aFe cold air intake, new spark plugs, smitybilt XRC front and rear-end and tire carrier (lots of weight) plus utilizing the Superchip Traildash 2. Recently replaced the rad cap and thermostat (195f). I live in Cabo San Lucas; basically at sea level.
Overheating symptoms - When I go for drives up the coast to Toto Santos this morning (this is has been on ongoing issue) the Jeep experiences cyclical overheating issues meaning the engine coolant goes from 200f to 230 back to 200f over a 3 minute cycle. The TFT average was 167f in town; low 157 the highway and high 170 (for all of 15-20 seconds) in town climbing a steep hill in Pedregal. ECT hit 230 numerous times and 234 twice until I turned on the AC to assist cooling down the ECT. Transmission flush about a year ago. The AIT temp high was 154f while outside engine compartment air temp was 75f.
Transmission Hunting - I think I know the answer (gear related) to this one but I want to double check. The transmission is not shifting properly meaning when shifting from 3rd to 4th or 4th to 5th, the RPMs are revving high while climbing a sligt incline. I either have to take the foot off the gas to allow it to shift or floor it to get it up to a higher speed and then it shifts. This happens in all gear ranges. No issues going down hill. The Superchip is set for 3.73 gears, actual tire height (34") and tire pressure, 35psi at the moment. Transmission temp does not seem to be an issue when the ECT rises to 230f.
thoughts? Looking for suggestions here in Cabo
Transmission Hunting - I think I know the answer (gear related) to this one but I want to double check. The transmission is not shifting properly meaning when shifting from 3rd to 4th or 4th to 5th, the RPMs are revving high while climbing a sligt incline. I either have to take the foot off the gas to allow it to shift or floor it to get it up to a higher speed and then it shifts. This happens in all gear ranges. No issues going down hill. The Superchip is set for 3.73 gears, actual tire height (34") and tire pressure, 35psi at the moment. Transmission temp does not seem to be an issue when the ECT rises to 230f.
thoughts? Looking for suggestions here in Cabo
03-26-2017, 10:21 AM
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When I went from 3.21 to 4.88 in my 2014 (35" tires), gear ratio set with an AEV ProCal, I started experiencing the same heat issues, ECT would get to 230-235. Never had a CEL or anything, but it still concerned me. Had the Jeep at a dealer for a solid 7 hours and they could find nothing wrong. I would open the windows, point the dash vents to the outside, and crank up the heater to keep it down.
It doesn't like to shift into 5th when accelerating to speed on the freeway but I'm thinking that might be because of my gear ratio.
I resolved some of the heat issues with a HyLine Offroad hood louver. I dropped 10-15 degrees after doing that.
It doesn't like to shift into 5th when accelerating to speed on the freeway but I'm thinking that might be because of my gear ratio.
I resolved some of the heat issues with a HyLine Offroad hood louver. I dropped 10-15 degrees after doing that.
03-26-2017, 10:22 AM
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sounds normal for 34" tires with 3.73's. my first jeep did that with stock tires and 3.21's. did you accurately input the tire size? These things run hot. Also tranny temp is somehow connected with coolant temp because I have the evic and when I put it in neutral tranny temp reads same as coolant temp.
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03-26-2017, 01:28 PM
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The 3.6 does heat up under load. I can tell you from experience that 230 degrees is pretty standard when climbing hills. I live in the CO mountains and my 2016 sees those temps regularly on any significant hill climb. If it normally operates at 200 - 210 under daily driving conditions and briefly rises to 230 - then you have a standard issue JK with nothing to worry about.
Thermostats - replacing the thermostat with a cooler model likely won't accomplish anything. As you likely know, the thermostat temp is simply the temperature at which it opens. Once open, coolant temp is dependent on load and cooling capacity. For example, You could put in a 160 but that's not the temp the coolant will stabilize at. It will still run at 200 and on up to 230 unless you add cooling capacity through a larger radiator, more fan, etc.
Thermostats - replacing the thermostat with a cooler model likely won't accomplish anything. As you likely know, the thermostat temp is simply the temperature at which it opens. Once open, coolant temp is dependent on load and cooling capacity. For example, You could put in a 160 but that's not the temp the coolant will stabilize at. It will still run at 200 and on up to 230 unless you add cooling capacity through a larger radiator, more fan, etc.
03-26-2017, 01:47 PM
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Thank you, SanJanJK.
Has your JK hit 230+ in neutral, or just idling or driving in a flat roads? As mentioned, my JK goes from 200 to 230f all day long while climbing, driving on normal road conditions.
Normal driving conditions usually sees the ECT gauge stay around 200-210. It's tough watching it hit 230+ over and over and what what damage is being done to the engine during normal driving conditions. I thought maybe the transmission Hunting could be the cause?
Has your JK hit 230+ in neutral, or just idling or driving in a flat roads? As mentioned, my JK goes from 200 to 230f all day long while climbing, driving on normal road conditions.
Normal driving conditions usually sees the ECT gauge stay around 200-210. It's tough watching it hit 230+ over and over and what what damage is being done to the engine during normal driving conditions. I thought maybe the transmission Hunting could be the cause?
03-26-2017, 02:26 PM
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I have not seen temps over 230 while driving on flat roads. But this assumes driving in the correct gear at 2000 +/- rpm.
A transmission that is constantly hunting and an engine that is rev'ing, as you described, will generate a great deal of heat. This will show up in your coolant temps.
Don't let it hunt. Try taking it out of automatic and driving in a set gear appropriate for the road and speed. If you manage rpms around 2000 it will be immediately apparent if the transmission is your heat issue. Your temps should stabilize well below 230...
I don't have a chip so can't comment on the impact a chip could be making on your shift points.
A transmission that is constantly hunting and an engine that is rev'ing, as you described, will generate a great deal of heat. This will show up in your coolant temps.
Don't let it hunt. Try taking it out of automatic and driving in a set gear appropriate for the road and speed. If you manage rpms around 2000 it will be immediately apparent if the transmission is your heat issue. Your temps should stabilize well below 230...
I don't have a chip so can't comment on the impact a chip could be making on your shift points.