Overheating issues

[limeliam]

Did you ever ensure the radiator was completely full?

The other day after my first burp I had to refill it. I will check today after work to see the levels

 

[KingCarGuyZ]

I did do the funnel twice with my first two burps but I will probably do a third on a steep incline to ensure the air flows out

Make sure to let the jeep warm all the way up to temp so the thermostat opens. What thermostat are you running?

 

[limeliam]

Make sure to let the jeep warm all the way up to temp so the thermostat opens. What thermostat are you running?

195 and whenever I did burp it I would turn on the heat and leave it going for about 20-30 min while squeezing the hoses

 

[Harold&Cat]

Do you still have the other radiator that was fine except for idling ? If so , put it back in and see if it still has problems at highway speeds . If it fixes the overheating at highway speeds , then change your fan clutch to the Hayden 2771 and see if that fixes the overheating at idle . Sounds like a new problem created after changing the radiator . Did it work correctly immediately after installing the CSF ?

What brand thermostat is in it ?

 

[limeliam]

Do you still have the other radiator that was fine except for idling ? If so , put it back in and see if it still has problems at highway speeds . If it fixes the overheating at highway speeds , then change your fan clutch to the Hayden 2771 and see if that fixes the overheating at idle . Sounds like a new problem created after changing the radiator . Did it work correctly immediately after installing the CSF ?

What brand thermostat is in it ?

Napa thermostat, and I did remove the grills so today going to work I’ll see if it helps

 

[MikeE024]

Ensure you have a propper coolant mix, running thick (more than 50%) coolant will lead to overheating issues.

I’ve ran 70% coolant in an attempt to slow down a rusting block. This was in the AZ summer with a turbo and caused no problems.

The overheat light in the TJ dashes doesn't come on until 240* (the gauge is really just an overgrown idiot light) hitting that temp regularly, you could have damaged your head gasket. I would look into checking the coolant for compression gasses and ensure you are not burning any coolant or any water in the oil.

The light came on around 260* for me at the emissions station on my first drive. The 4.0L is quite durable.

 

[KennethS]

I did remove the grills so today going to work I’ll see if it helps

What do you mean by plastic grills? The TJ doesn't have any plastic grill pieces. It should look like this.

View attachment 692474

A picture might provide some significant information.

 

[KingCarGuyZ]

I’ve ran 70% coolant in an attempt to slow down a rusting block. This was in the AZ summer with a turbo and caused no problems.



The light came on around 260* for me at the emissions station on my first drive. The 4.0L is quite durable.

Interesting - If I run more than 50% i see a notable (10* or so) jump in coolant temp, running the Zertex G05. I am kinda anal about monitering temp with an ultra-gauge though. I doubt it would be enough to show on the stock gauge.

I wound up running about a 40% coolant 60% water solution with Redline Water-wetter that still gives me protection down to -20ish (way more than we will ever see in DFW) but cools much better in the humid texas heat.

 

[MikeE024]

Interesting - If I run more than 50% i see a notable (10* or so) jump in coolant temp, running the Zertex G05. I am kinda anal about monitering temp with an ultra-gauge though. I doubt it would be enough to show on the stock gauge.

I track my ECTs, IATs, boost pressure, and transmission temps in real time on aftermarket gauges.

I expected to see ECT issues when running that high of a coolant percentage, but it simply didn't happen. I tracked the percentages with a refractometer.

I wound up running about a 40% coolant 60% water solution with Redline Water-wetter that still gives me protection down to -20ish (way more than we will ever see in DFW) but cools much better in the humid texas heat.

Water Wetter is known to not do much when using coolant, but I still tried it. I stopped using it since I couldn't tell a temperature difference and it created brown oily sludge (another known issue for some running coolant). FWIW, I also didn't notice a penalty with my IATs when switching from water / Water Wetter in my intercooler to water / G05.

Your boiling point is a bit lower at 40% but still looks good since the 18psi radiator cap does the heavy lifting. Corrosion is known to set in once you get much lower than that.

 

[B.E. Coyote]

Yeah, I replaced last year with Hayden fan clutch

I am going through kind of the same. I'm still not where I want to be but I had just replaced all of cooling system and discovered that the brand new Hayden HD clutch was bad. I put in a new Hayden SD fan clutch and it is doing much better. I went on amazon and bought a cheap anemometer to measure airflow in front of the condensor and a laser tach to measure the rpm of the fan. After comparing numbers to a fan test I saw on youtube I realized the brand new fan clutch was bad. I can at least drive the jeep now. My pre-cats are showing bad also, hoping that after I change them this week with a walker set that the temp drops even more, if not I may still try a different radiator. I put a denso in but have read in a few places that others do a better job.

 

[B.E. Coyote]

I run a CSF 3 row, with an E-fan and a bunch of small tweaks - I hold 195* in 100* heat with the A/C on idling - I do see 210ish going down the highway, sometimes 215 if I am really booking it (85+) but never over that.


I know it sounds simple, but have you properly bled the system? A funnel kit will allow you to completely bleed the system, many people belive the Jeep will bleed automatically from the overflow tank - I haven't had good luck with this.

I would also check your Thermostat and make sure you have a good one with an appropriately sized bleed hole. Stant and Renshaw 195* come recommend. Ensure you have a propper coolant mix, running thick (more than 50%) coolant will lead to overheating issues.


The overheat light in the TJ dashes doesn't come on until 240* (the gauge is really just an overgrown idiot light) hitting that temp regularly, you could have damaged your head gasket. I would look into checking the coolant for compression gasses and ensure you are not burning any coolant or any water in the oil.

Do you think that radiator would be just as effective with the stock fan?

 

[KingCarGuyZ]

Do you think that radiator would be just as effective with the stock fan?

I think the radiator was so affective for me because mine was overdue for replacement. The rest of my coolign system was dialed and the radiator was just the last piece of the puzzle.

considering the E-fan is working at 30-50% load most of the time, I think a factory fan would be more than enough to keep the jeep cool with a CSF 3-row. The bigger upgrade for me was the coolant filter so I didn't have to replace the radiator again next year - but thats just the junk in my block and my system that not even a flush could get out. your milage may vary.

 

[B.E. Coyote]

I think the radiator was so affective for me because mine was overdue for replacement. The rest of my coolign system was dialed and the radiator was just the last piece of the puzzle.

considering the E-fan is working at 30-50% load most of the time, I think a factory fan would be more than enough to keep the jeep cool with a CSF 3-row. The bigger upgrade for me was the coolant filter so I didn't have to replace the radiator again next year - but thats just the junk in my block and my system that not even a flush could get out. your milage may vary.

Your seeing way better numbers than me. Today was 90 degrees, 210 at idle with no AC, 217 at idle with AC and it climbs to 230 and maybe more under load while driving. At least now the temps will go back down with the new fan clutch. Hoping the new pre-cats help or fix it. If not, I'm going to swap out the new Denso. May look into the filter. When I got the the jeep in October the coolant was disgusting.

 

[MikeE024]

Your seeing way better numbers than me. Today was 90 degrees, 210 at idle with no AC, 217 at idle with AC and it climbs to 230 and maybe more under load while driving. At least now the temps will go back down with the new fan clutch. Hoping the new pre-cats help or fix it. If not, I'm going to swap out the new Denso. May look into the filter. When I got the the jeep in October the coolant was disgusting.

Looks like you need a properly working radiator imo. We know it’s more than a fan problem since you have even worse issues when driving at higher speeds (—>radiator). I doubt it’s your pre-cats considering you’re able to drive at highways speeds (so they are flowing).

I wouldn’t jump to a coolant filter unless you know it’s needed, and my guess is you haven’t done enough flushes to have that answer (it takes time to know how well your coolant holds up to corrosion). Flushing / reverse flushing your radiator will tell you if it’s getting plugged up. Actually, simply pulling the radiator cap will give you an idea since the larger problematic bits will clog up the channels directly below your radiator cap.

Also, a coolant filter doesn’t solve this since it runs in parallel, but mine is nice for keeping the quality of my coolant more like new. I solved the bits getting in my radiator by installing a screen/trap between the thermostat housing and the radiator. I can remove the trap’s cap and suck out any bits that are caught before filling it back up (about a cup worth of fluid). Eventually I’ll get a different block in there and not worry about this stupidity.

 

[B.E. Coyote]

Looks like you need a properly working radiator imo. We know it’s more than a fan problem since you have even worse issues when driving at higher speeds (—>radiator). I doubt it’s your pre-cats considering you’re able to drive at highways speeds (so they are flowing).

I wouldn’t jump to a coolant filter unless you know it’s needed, and my guess is you haven’t done enough flushes to have that answer (it takes time to know how well your coolant holds up to corrosion). Flushing / reverse flushing your radiator will tell you if it’s getting plugged up. Actually, simply pulling the radiator cap will give you an idea since the larger problematic bits will clog up the channels directly below your radiator cap.

Also, a coolant filter doesn’t solve this since it runs in parallel, but mine is nice for keeping the quality of my coolant more like new. I solved the bits getting in my radiator by installing a screen/trap between the thermostat housing and the radiator. I can remove the trap’s cap and suck out any bits that are caught before filling it back up (about a cup worth of fluid). Eventually I’ll get a different block in there and not worry about this stupidity.

What radiator are you running or recommend? This is a brand new denso.

 

[rasband]

Double check what coolant you put in the system, they're not all compatible.

If you mixed the NAPA coolant (OAT) with the TJ OEM coolant (HOAT: mopar, zerex g05) the issue isn't likely related to the radiator(s) you've used. You probably made a sludge in your system and compromised the cooling capacity of the system because the coolants are incompatible and turn into a kind of gel rather than free flowing fluid.

I don't know how you fix creating a sludge in your system, but it seems likely to be your problem.

 

[MikeE024]

What radiator are you running or recommend? This is a brand new denso.

I’m running a Mopar.

I don’t know the answer since I’ve seen both good and awful testimonials for the aftermarket offerings. The quality seems to be very inconsistent from one part/lot to the next.

 

[Rygrego]

Need some help. Last year I did an entire cooling system rehaul and had no issues. The radiator I got was an okay one until it started to hit 100s outside, idling with AC on for about 20 min would go to red on the temp gage. I replaced with CSF two row all aluminum radiator and now I’m having overheating issues when on highway speeds Jeep will hit 220 with heater on. Never had any of these issues with my previous radiator, only overheating with idle and ac in the heat. I saw some coolant dried up around the radiator cap so I replaced with 18 NAPA one and after driving home the overflow resivor was bubbling. I took the cap off and let it cool down. I noticed it dranks lots of coolant all the way under the add line. I had to drive to work and didn’t have time to add coolant till the fill line. On the highway with the heater on it was still hitting 220. I’m surprised it drank that much coolant after i burped it twice and saw no air bubbles come out. Sorry for the long post just wanted to throughly explain it. You think it’s the radiator, a stubborn air pocket, or possibly a head gasket? Thanks

I installed a CSF 3 Row , a Hayden 2791 fan clutch (severe duty) and a 195 thermostat. And have not had a heating issue since. The fan can be a little noisy, but only at low speeds.

 

[Harold&Cat]

I flushed mine out using a water hose with a pool/hot tub pre-filter . Had the water pump off flushed it until all clear . Drained everything as much as possible installed the water pump and did it again . Then I installed the new radiator . After draining , filled with antifreeze and distilled water . About six months later I flushed it out again . Post number six of this thread describes my setup .
Slow moving stays below 210 , idling with AC on for extended periods of time it will sit on 210 . AC blows cold sitting and idling and freezes you while driving . Highest I've seen it at highway speeds was just to the right but touching 210 on the gauge . This is in the 95 degree Louisiana heat .

 

[limeliam]

So bad news, I was driving for about an hour and a half on the interstate with the AC on. Temps hit about 220 but as soon as I was slowing down in the parking lot within three min the temp would back to 210. I saw that a bunch of coolant spilled near the resivor. Not sure if it’s pressure or what or if it’s the cap which I replaced or maybe a leak in the resivor. Then after it cooled down it sucked almost all of coolant from the resivor, but the actual radiator is always full. Very frustrating, so I ordered a brand new mopar oem thermostat and resivor that I will install with the new fan clutch and see how it does. Could it be an air pocket that’s causing this? I’ve burped this jeep with the funnel at least 4 times and I never see any bubbles come up with heat on
and idling for 20 min. My coolant never boils and there is no oil in it so I assume it can’t be the head gasket. Any thoughts before I install all the stuff with the new radiator?