Jeep Wrangler Forum banner

1 - 20 of 127 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I have a 2017 JKU that recently underwent lift/regear. I run 35s on a 3.5” lift and 4.56 gear ratio. I put on steel front/rear bumpers and sliders. Today I was driving uphill on freeway about 75-80 mph on a 7% grade for about 3 miles with A/C on. At the top of the climb my temperature light went off and I pulled to the side. Let the Jeep cool for 20 minutes and checked fluid levels/fan. Drove home another 40 miles with no issues and temp range between 203-231. Engine coolant half full, radiator level totally full, fan works, no leaks, and no mud caked on the radiator. Put a winch on two months ago and haven’t had issues off-road or on similar grade ascents until today. I am hoping it’s a one off event due to combo of A/C and uphill grade - but I would think I should have no trouble with 7% grade on an 80 degree day. Any thoughts or ideas?
 

·
Registered
Joined
·
8,924 Posts
T-stat?
You'll have to keep a watchful eye for a while.
My t-stat failed but failed in the open position.
 

·
Registered
Joined
·
1,538 Posts
Sorry to say that is pretty normal for a 3.6 JK. 203-240 temps are a regular occurrence and my JK overheats pretty much every time I go off road. Computer will turn on the fan at 226F. But it will not be able to keep up with cooling. So this is a sad reality of a 3.6 in a jk. There is a lot of threads on this problem and what can be done and the general consensus is not much. Some have tweaked the programming with software, not just a programmer will do it!, some have upgraded the radiator.

I am sure what you will get with this thread is a bunch of people saying it isn't normal, that is because the don't know their JK does this, mostly because the temp needle doesn't move from center until over 235. But otherwise the rest that aren't aware is because there isn't 7% grade that last long enough to overcome the ability of the fan. In Colorado I see temps in the 240s regularly and as I said I overheat every time I off road.
 

·
Registered
Joined
·
8,924 Posts
Sorry to say that is pretty normal for a 3.6 JK. 203-240 temps are a regular occurrence and my JK overheats pretty much every time I go off road. Computer will turn on the fan at 226F. But it will not be able to keep up with cooling. So this is a sad reality of a 3.6 in a jk. There is a lot of threads on this problem and what can be done and the general consensus is not much. Some have tweaked the programming with software, not just a programmer will do it!, some have upgraded the radiator.

I am sure what you will get with this thread is a bunch of people saying it isn't normal, that is because the don't know their JK does this, mostly because the temp needle doesn't move from center until over 235. But otherwise the rest that aren't aware is because there isn't 7% grade that last long enough to overcome the ability of the fan. In Colorado I see temps in the 240s regularly and as I said I overheat every time I off road.
I've never dinged the temp idiot bell even pulling my overweight teardrop up hills with 3.73s/33s manual trans. I've hit 230 degrees but never higher.
I've got about 126,000 miles on the mill and have R&R'd the coolant once.
 

·
Registered
Joined
·
1,538 Posts
I've never dinged the temp idiot bell even pulling my overweight teardrop up hills with 3.73s/33s manual trans. I've hit 230 degrees but never higher.
I've got about 126,000 miles on the mill and have R&R'd the coolant once.
I have only gotten the warning 5 times or so, so not too bad. But I know it happens so I EIVC to Coolant when in 4LO or headed to the high county, which I am going to guess you don't have, and as soon as I see 235, I back off. The temp needle never moves... I know how to handle it now.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
Thanks for your responses. I’ve been doing more research and it does sound common - which is unfortunate. I plan to monitor the temp closely and see if the issues persists. Maybe I will keep the A/C on low just to engage the fan prior to hitting 226 degree where it turns on automatically. A lot of added weight plus +3000k on long/steep ascent could have just overdone it. Will be more careful going forward.

No hot oil light. Just temp warning light. Didn’t get a read on what the temp actually was at that time - too busy trying to pull over on the freeway!
 

·
Super Moderator
Joined
·
7,683 Posts
Thanks for your responses. I’ve been doing more research and it does sound common - which is unfortunate. I plan to monitor the temp closely and see if the issues persists. Maybe I will keep the A/C on low just to engage the fan prior to hitting 226 degree where it turns on automatically. A lot of added weight plus +3000k on long/steep ascent could have just overdone it. Will be more careful going forward.

No hot oil light. Just temp warning light. Didn’t get a read on what the temp actually was at that time - too busy trying to pull over on the freeway!
The condition seems common. The tire wheel combo is probably not helping either. Your thermostat could be lazy, I would check into that. I would also turn the AC on, and blow maximum heat through the unit, not cold air. The heater core acts as a small radiator, and turning the blower onto max heat will drop coolant temperature a bid faster. Turning on AC will also force the radiator cooling fan to run, although once the engine hits 226F the fan comes on with or without the AC running.
 

·
Registered
Joined
·
6,013 Posts
When I pull the teardrop through the co mountains, I have the heat on high and all the windows down. The heater works great to cool down the engine a bit but sure does warm up the cab.
 

·
Super Moderator
Joined
·
8,186 Posts
Where is your winch mounted - is it in front of radiator? Do you have those grill insert or angry grill things? Both would be blocking flow of cooling air when you need it most.
 

·
Registered
Joined
·
615 Posts
Check to see if your radiator fins are plugged up with mud, bugs, etc. That will really hinder your cooling system and lead to hot temps.
 

·
Registered
Joined
·
1,603 Posts
Sorry to say that is pretty normal for a 3.6 JK. 203-240 temps are a regular occurrence and my JK overheats pretty much every time I go off road. Computer will turn on the fan at 226F. But it will not be able to keep up with cooling. So this is a sad reality of a 3.6 in a jk. There is a lot of threads on this problem and what can be done and the general consensus is not much. Some have tweaked the programming with software, not just a programmer will do it!, some have upgraded the radiator.

I am sure what you will get with this thread is a bunch of people saying it isn't normal, that is because the don't know their JK does this, mostly because the temp needle doesn't move from center until over 235. But otherwise the rest that aren't aware is because there isn't 7% grade that last long enough to overcome the ability of the fan. In Colorado I see temps in the 240s regularly and as I said I overheat every time I off road.
This is exactly right. As someone else mentioned, turning the heater on will cool it off pretty well, at the expense of your comfort.

BTW, I'm one of those who's changed both the fan start temp and upgraded the radiator. I won't know till the weather warms up and I head to the mountains again whether the upgraded radiator was worthwhile.

Mark

Sent from my SM-G935V using Tapatalk
 

·
Registered
Joined
·
6 Posts
Yes - the winch is mounted on top of front bumper and I do have grill inserts. This setup has been in place since January and I had no issues until last weekend. I did a few off-road trips in Big Bear and J Tree with some significant elevation gain. Although temps in SoCal were a bit cooler at that time then.

I checked the radiator and saw no mud build up.
 

Attachments

·
Registered
Joined
·
1,603 Posts
Ditch the grill inserts, for sure. They are just decoration, and serve no useful purpose.

Mark

Sent from my SM-G935V using Tapatalk
 

·
Super Moderator
Joined
·
8,186 Posts
If you have concern about engine temp, the winch needs a bumper that mounts it low between frame rails - and grill inserts do nothing but block air flow.
 
  • Like
Reactions: Fungun

·
RETIRED MODERATOR
Joined
·
51,169 Posts
If you have concern about engine temp, the winch needs a bumper that mounts it low between frame rails - and grill inserts do nothing but block air flow.
^^^X2, plus, I don't see a air dam. These are all contributors to higher coolant temperatures.

O'H..I flipped your PICS for you.
 

·
Registered
Joined
·
1,603 Posts
If you have concern about engine temp, the winch needs a bumper that mounts it low between frame rails - and grill inserts do nothing but block air flow.
That's true, but mine is buried in the bumper and it'll still get hot on tall passes. Lowering the winch is worth doing, but is unlikely to make coolant temps drop meaningfully, by itself.

Mark

Sent from my SM-G935V using Tapatalk
 

·
Registered
Joined
·
6,013 Posts
That's true, but mine is buried in the bumper and it'll still get hot on tall passes. Lowering the winch is worth doing, but is unlikely to make coolant temps drop meaningfully, by itself.

Mark

Sent from my SM-G935V using Tapatalk
Yep, my which sits between the frame rails as well. I still get hot on steep grades. I just know that as I approach the grade, windows go down and heat goes on high.
 
  • Like
Reactions: trashmanssd

·
Registered
Joined
·
6 Posts
Discussion Starter #20
I am going to take out grill inserts. As of now my options are limited with the winch mount. I am going off-roading this weekend. This trail involves some very steep climbs. I did it recently with no issues. I will monitor temps and let you know. Will employ A/C fan and blast heat if needed.

I tested on the freeway today and my highway temp is about 221-224F, high of 228 (up inclines) going 70 mph. High heat & A/C fan brought it down to average 217-219F, and low of 212F. I’d say it provides about 6-8 degrees of relief on average. Hopefully it will improve further after taking out grill inserts.
 
1 - 20 of 127 Posts
Top