I’m gonna dig up an old thread here. Occasionally my temp will get above 240*. I’ll see 242, 243 if I’m going up a hill. It doesn’t stay that temp for long, maybe a minute or so then it drops down to 220 quickly. However, I feel that’s too hot still even for a minute. I doubt I’ve damaged anything with that coolant temp but I still want to address the issue. I think the max temp should be around 230 even though at 240, the temp needle wasn’t even at 3/4.

So, to my point… I’m considering a larger aluminum radiator and was considering the afe rad. Anyone have experience with this that can comment? Or any other good aluminum radiator? I also may try to figure out a way to get the fan to come on sooner as well to help drop the temps before they get too high.

 

I'd expect that you are seeing similar ambient temps that I see here in DFW. Before I installed my Griffin radiator this is similar to what I was seeing, specifically when temps would get up over 100°. I have a 30 minute commute from work to home that is almost all interstate driving. It wouldn't be uncommon for me to see the temps creep up over 240° during that drive with my engine revving up around 3k rpms. Ususally I'd just back off the throttle and temps would come back down. I really believe my issue is more about airflow and blockage with my PSC bumper, a light, and which blocking the grill more than anything, but the Giffin did seem to help a little bit, though it did not completely alleviate higher temps completely. If I know I might be encountering rising temp situations I typically force my fan on high with my programmer and that really keeps things under control. Sixty4x4 has suggested making sure everything around the fan shroud is sealed up and that there's no air "escaping" the path directly over the radiator which makes a lot of sense. Every little bit helps.

Back when I purchased my Griffin I looked around a good bit and the AFE was one I was focussing on as well. In the end the Griffin wasn't much more expensive than a new Mopar unit and it had a larger capacity. I couldn't really justify the price of the others in my head. I found a few bits about the AFE on some other sites, if I recall, but feedback was sparse. I'm ok with the Griffin. If it had cost a couple hundred more I'd probably be a little disappointed. I do seem to notice small bit of coolant around the cap/neck from time to time and that pisses me off. I hate that stupid cap they have.....and the fact it costs $20 on top of the rad is aggravating.

I have a few comparison pics in this thread if you hadn't seen it yet -
https://www.jk-forum.com/forums/stoc...nstall-354457/

 

I may have mentioned it before but here it goes .. I believe you can replace your thermostat with a cooler one and go in to the ECU program and tell it what the new temp is and change the fan stage setpoints. 240* is just plain too hot especially for you southern guys. Also you will get more high end rpm advance under power as detonation will be further away with lower water temp. I run my V8 on a 95F day here on a stock 3.8 rad and never gets over 95C (203F) even crawling on steep hills.

 

Russ, your since your griffin radiator install, have you been happy with it? The biggest complaint I see with these aftermarket aluminum radiators is leakage. How is yours holding up?

Sixty, it’s interesting that the smaller stock radiator is keeping your v8 cool. I would love to just toss in a new thermostat and program the computer for it. I’ll look into that but am somewhat concerned about jumping down a rabbit hole of computer issues and engine performance issues. I have the JScan app so I’ll dig around there and see if there’s a setting to tell the computer about a thermostat.

I don’t exactly know if a minute or two of 240 degrees is bad but it definitely doesn’t appear to be very good based on the searches I’ve done. I think I’m borderline on dangerous so there obviously needs to be a fix. I’m thinking if a stock radiator can cook a v8, then maybe my radiator isn’t the problem if it doesn’t leak.

 

The Griffin has been ok. I've not had any issues with it leaking from a crack, though this cap does appear to have an issue from time to time. The cap is larger so you can't re-use the factory. I've done what Sixty4x4 and others suggested previously and that was to add blue loctite to the mounting bolts and not crank em down all the way, giving it a little more flexibility when wheelin. It sure seems like I've had this longer than 13 months. It did seem to help my issue a bit. After installing it I really kept my eye on temps to monitor apples-to-apples situations best I could. I would not tell you this is the end-all-be-all radiator that you just have to go purchase though.

I think the lower thermostat and programming is an intriguing idea, though I think you're really going to have to dive into HP tuners to set that in the ECU. I'm not sure Jscan or many of the other programmers can do that, though I could be wrong. I've always just been noncommittal when it comes to dumping more money into programming for my use. I've also always just found diving too deep into tuning has always been a can of worms for me.

As far as temps, I have no concerns with 240° on the random occasion, though it's not thrilling to see. My understanding has always been that 250 is the REAL danger zone. If I was running there constantly I'd be concerned, but the occasional blip doesn't worry me. The 3.6L always seemed to run a bit hotter than the 3.8L and I would say that my normal temp is in the 215-222° range on an average day. I've got 105k on my 3.6L over 8.5 years. Maybe its life will be shorter than normal in the long run....idk. Guess time will tell.

 

I have been reading up a bit on cooling systems and how they can be improved and also about the jk’s cooling system. You’re right Russ in the fact that the jk is designed to run a bit on the warm side. If 195-220 is a normal operating temp, then being 10% above that for short times doesn’t raise any alarms for me.

As for swapping the thermostat, in my mind, that won’t fix the issue but only open a rabbit hole for other potential tuning issues. A lower thermostat will open sooner and give the coolant a head start on cooling. The factory thermostat will open at 203 degrees, so once the coolant reaches 203 degrees (like it will regardless since that’s normal operating temp for the 3.6) then having a lower thermostat doesn’t help me out. So I don’t think I’ll mess with a thermostat swap. Also, if a stock size radiator is cooling sixty’s v8, I’m thinking it’s sufficient for my 3.6. So… now what?

I may have a shop flush the system. There could be gunk that’s built up and reducing the efficiency of the system. However, if I’m momentarily reaching slightly less than 10% over the normal operating temp, then maybe I’m just being paranoid and trying to fix something that’s not broken?

 

Is it really just the summer temps driving this issue like I was seeing? The rest of the year I don't really see issues, it's just when the oven here in DFW really cranks up. I know that my situation would be greatly improved by removing my winch, but that ain't gonna happen. It was after my final bumper swap to my PSC BFH that I really noticed the changes for me. I previously had bumpers that recessed the winch and allowed a bit better airflow over the radiator. I think this is also reinforced with the fact that if I force the fan on high to draw more air over the radiator I don't really have an issue. Just in July when I towed my trailer out to Moab I had great success just leaving the fan on high. I couple of times I'd stop to get gas and forget to turn the fan back on......and I'd notice the temps getting high when heading up a pass in Colorado (with my BullyDog I have to turn that setting on each time the ignition cycles).

 

Yea, mainly the summer temps. Yesterday I drove back from a trail and going up hills revving at about 4-5k and temps around 95 or so I hit 242 degrees. Once the transmission up shifted or I let off the gas it cooled down quickly. Other than that, the temps never got higher than maybe 225-230.

My winch is recessed in the frame rails and the only thing in front of my radiator is my steering cooler.

I don’t think I have any options on JScan to control my fan settings. I looked through it and only found a setting to change the fan type as far as it’s impedance and wiring type.

 

SV if you change your mind about the T'stat change if you can locate someone with HPT around Prescott area then all it costs you is 2 x $50 credits to access your program and make the changes and while you are in there alter the PE F/A ratio (make it richer), RPM to activate from 4600 down to about 2800 and time to activate settings (I think 90secs @ full throttle <yes 90> down to 1 sec) for Power Enrichment. Also once you buy the credits basically the credits in the program are only good for your VIN. But I would find a fellow that knows about Jeeps to do this. Or send me the file and I will investigate what to change and advise you as you have to do the inputs on your license.

 

I drove to and from Phoenix today. On the way home while in Phoenix it was 115*. At 80mph cruising at 3200 rpm, the temp gauge was at 230*. A whopping 5* above “normal” operating temp.




Phoenix is at 1000 ft above sea level, Prescott is right about 5200 ft above sea level. While climbing through the mountains to get home (temp dropped to 113 outside) I was cruising at about 70 mph. The temp gauge got right around 240. It wasn’t long before it dropped back down to 235.





Given this info, I’m not too worried about any over heating. I made a bad assumption before that my temp was too hot.