Is overheating an issue?

waporvare

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I have a 2021 Wrangler Rubicon with an unmodified Ecodiesel. It does have a Tazer mini installed, but that does not affect engine performance in any way. It has LoD Destroyer front and rear bumpers and tire carrier, and is running on 35x12.5 BF Goodrich T/A tires on stock wheels. I have a R-Pod 171 Trailer that runs 2500 pounds empty that I tow from time to time.

The front bumper and Warn winch I have sit low and do not interfere with the radiator, which is why I bought that particular setup. I have no lights above the bumper – just the fog lights in the bumper itself.

Even when not towing, this diesel runs hotter than any diesel I have ever owned. Of course, I have only owned Cummins diesels before, and perhaps they run cold. So I get nervous watching the gauges on this Ecodiesel sometimes. The fact is that 240 degrees on any engine is friggin hot, and it hits that going up grades at speed in high ambient temperatures whether towing or not. The gauge goes up to about half slowly, but as soon as it hits halfway if I keep my foot in it, the rise is fast. Towing on long grades, I have to slow down to keep the heat down. So a 7% grade loaded and towing has me backing off the throttle and maybe doing 50 or less just to keep the temperatures down. No problem with power, as it would easily pull hard and fast up just about any grade I encounter on highways or the interstate, but heat is an issue.

Last week, I pulled off the hood liner and opened the hood vents with a Dremel tool, to make them operational instead of cosmetic in hopes of getting some more air moving through the radiator because that is clearly the limiting factor. The only other thing I can see that would be an easy mod would be to move the horns, since they block the air flow to upper corners of the radiator. The grill inserts do block maybe 3/4” of the total width of each of the grill openings, and maybe the edges of the JT grill inserts are a little thinner? I haven’t checked that.

All in all, this engine appears to run hot on purpose. I wonder what the thermostat is set at. It is definitely higher than 190, because the engine warms up past 210 immediately in any weather. That is perhaps why they are so picky about the oil, as those temperatures will cook any soot that is in the oil. Perhaps that is why the point of failure on these engines appears to be the main bearings filling with hard deposits. There are a couple YouTube videos showing this.

My plan is to see if the opening of the vents helps, maybe move the horns, take it easy on the hills (especially when towing), and try to keep the temperatures under 240. I hate to cook oil like this. So far, I am changing the oil at 5000 miles, and Blackstone Labs is saying my oil is fine, so I will keep changing it at 5000 miles.

The biggest thing I would think might help would be an aftermarket radiator with an additional row of coolant passages (another row in depth, that is), and perhaps a thermostat that is ten degrees cooler. I love the engine and the Jeep itself, but I hate to cook any engine like this.

EDIT — Just to make sure I am being clear, the engine temperatures I am talking about are oil and water temperatures as shown on the off-road gauges and the main gauges in the cluster. It is the oil temperature that I am most worries about, as it tends to run hotter than the water temperature. I am talking about changing the thermostat in hopes that a cooler engine may help keep the oil from spiking in temperature. I haven’t looked at the oil cooler to see if it is part of the radiator (like the transmission cooler often is). If the oil cooler is separate, like it should be, then a larger oil cooler or a better placement would definitely help.
Did the hood vents being opened help any? I've been considering doing this mod.





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DEZELJP

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Doing the S&B Filters Hood Scoops on the JL and Gladiator. They seem nicely designed and have rubber caps to keep the PNW rain out when you don’t need the extra air. Monday was 116 degrees, today 71 so can’t make heat comparisons. Should be a fair start at helping with a little heat, air is being rammed straight in to engine compartment over exhaust. Moving the horns on the Gladiator this weekend since the bumper and grill will be off. Just off the insides of the frame behind bumper looks hopeful. Already have JT grille swap on the JL. @Mjolimar I‘ve pulled a 25ft travel trailer for 6yrs with my Grand Cherokee EcoDiesel. Motor has plenty of power just might have to baby the JL on hills with altitude. I always baby the GC, I’m pulling close to 6000lbs. We’ll put the JT to the test when we get the chance. (yes family of three EcoDiesels.

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Mjolimar

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To waporvare: It is hard to tell if opening the hood scoops on my Wrangler has helped, as we have had outside temperatures that are in the 108-117 range for the past few days, so the darn thing is still as hot as can be. Once temperatures return to something like normal, I should be able to tell if it makes a difference. It certainly cannot hurt.

To Dezeljeep: The S&B scoops look interesting, but I would want them facing the other way, since I think the issue is getting air through the radiator and out through the hood, rather than in through the hood. If those do make a difference, though, please do let us know.
 

DEZELJP

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I’m on your same page. I was hoping a couple of months ago that If they made the Amfib snorkel for a diesel I would put one on each side and use them for air venting. That, didn’t happen so the thought is to take the left and right cowl covers from Mopar and create my own rear venting. Kid, said he could 3D print the vent at work and a little Bondo and sanding. It might still happen.
 

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I think the issue is getting air through the radiator and out through the hood, rather than in through the hood. If those do make a difference, though, please do let us know.
This! You would be surprised at how much heat escapes through the rear most vents on our Hoods.
 

Plongson

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I really like both ideas. I might first try removing the hexagon in the OEM. I really like the super clean finish on the underside with the aftermarket though. Any thoughts there??

Edit: Remove the plate UNDER the hexagon shape...I made this mod the other day and there appears to be a noticeable drop in the average coolant temp on the off road gauge. So far so good...

Here's my theory but depending on how well it works, it could change...and this cost me nothing but a little time.

The engine compartment is absolutely filled, that we can agree on. The only way for hot air to escape is back down the firewall and that route is restricted. If incoming cool air has nowhere to go, it will slow it's flow through the radiator, essentially bunching up. Reduced air flow, reduced cooling through the radiator. This is my problem with hood "scoops"...you're adding air that cannot be expelled.

Modifying the OEM hood "vents" allows for more air to be expelled top and bottom and reducing the "bunching" effect from not having a place for hot air to escape to.

look at my attachment photos and you will see what I mean. So far this seems to be working and I have no money invested. There is a downside and that is water can get in the engine compartment, but it has not rained here in the southwest in 20 years...lol...but that side issue is something I'm working on...So, I prefer the "Hot Air Out" style.

Jeep 1.jpg
Jeep 2.jpg
 
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waporvare

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I really like both ideas. I might first try removing the hexagon in the OEM. I really like the super clean finish on the underside with the aftermarket though. Any thoughts there??

Edit: Remove the plate UNDER the hexagon shape...I made this mod the other day and there appears to be a noticeable drop in the average coolant temp on the off road gauge. So far so good...

Here's my theory but depending on how well it works, it could change...and this cost me nothing but a little time.

The engine compartment is absolutely filled, that we can agree on. The only way for hot air to escape is back down the firewall and that route is restricted. If incoming cool air has nowhere to go, it will slow it's flow through the radiator, essentially bunching up. Reduced air flow, reduced cooling through the radiator. This is my problem with hood "scoops"...you're adding air that cannot be expelled.

Modifying the OEM hood "vents" allows for more air to be expelled top and bottom and reducing the "bunching" effect from not having a place for hot air to escape to.

look at my attachment photos and you will see what I mean. So far this seems to be working and I have no money invested. There is a downside and that is water can get in the engine compartment, but it has not rained here in the southwest in 20 years...lol...but that side issue is something I'm working on...So, I prefer the "Hot Air Out" style.

Jeep 1.jpg
Jeep 2.jpg
The hot air out style may actually help with bug and rock deflection I would think.
 

Plongson

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Also consider this, using the Tazer to manually run the cooling fan on HIGH is a huge benefit to expel unwanted heat through the hood vents.

Here's the underside...
20210706_093559.jpg
 

Compression-Ignition

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I thought the hood vents were non functional?
 

DEZELJP

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Here’s a pic of the underside of the vent. It’s none functional stock. They are cutting out the bottom lower half. You live on the right side of the state you can probably get away with running this way. I live in rainy Vancouver. I don’t want that much water in my engine compartment.

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Wizno

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I recently took a trip from AZ to NM with a lot of uphill driving while weighed down with camping gear and experienced quite a bit of overheating while driving uphill. I was trying to maintain 75-80 MPH, but as I overheated I had to go down to 50-60 for a bit.

Outside temps were under 100 in the areas where it was happening, and IIRC under 90.

There are a few factors that I think contributed to the overheating while driving uphill:
  • Weighed down with camping gear (Including custom drawer system)
  • Elevation - Seemed like it got worse with higher elevation, but can't confirm
  • Keeping it above 70 MPH (If you ain't first, you're last. lol)

I just reached out to aFe Power to see if any radiators/coolers are in the works for the EcoDiesel... hopefully there is!
 

AZ-Chris

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Last Friday (July 9) I made a round trip from Phoenix to Pine, AZ. Pine has an elevation of ~5,400 ft. Ambient temperatures in Phoenix were in the 105 degree range, while Pine was in the low 90s. On the long uphill climbs (6-7% grades) I saw my oil temps increase from 218 F up to a high of 251 F (gauge slightly above half) while speeds were consistently above 70 mph. Coolant never went higher than 225 F. This was my first mountain highway drive with the new lift and 37s (not towing). Oil temperatures returned to 220 degrees within 2 minutes of cresting the hills.

I will soon be taking a trip from Phoenix to Salt Lake City and will monitor how things go on that trip as well.
 

Cypher

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Last Friday (July 9) I made a round trip from Phoenix to Pine, AZ. Pine has an elevation of ~5,400 ft. Ambient temperatures in Phoenix were in the 105 degree range, while Pine was in the low 90s. On the long uphill climbs (6-7% grades) I saw my oil temps increase from 218 F up to a high of 251 F (gauge slightly above half) while speeds were consistently above 70 mph. Coolant never went higher than 225 F. This was my first mountain highway drive with the new lift and 37s (not towing). Oil temperatures returned to 220 degrees within 2 minutes of cresting the hills.

I will soon be taking a trip from Phoenix to Salt Lake City and will monitor how things go on that trip as well.
In AZ what mpgs do you see before vs after the lift and 37s?

My Eco-Diesel Rubicon is scheduled to be built in a few weeks so finalizing my build plans. I am torn between a 1 to 1.5" lift and 35s, or a 2" lift and 37s. For tires it's between the new Baja Boss A/T, Raptor 37" K02, or Ridge Grapplers. (I have run the K02 and RG on my other JLURs). I plan to keep this one lighter, and hope to build a M416 for camping.
 

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I made a round trip from Phoenix to Las Vegas a couple of months ago on my OEM suspension & tires (33" BFG K02) and averaged 30 mpg.

I will soon be taking a trip to Salt Lake City on my now lifted rig on 37s (an overall 6" lift). So far, after only 2 tanks of fuel, my average fuel economy is between 22 & 23 mpg, but I suspect a pure highway run may show better results, but this trip will see large changes in elevation.

My lift was done at Doetsch Off-Road in Chandler and was from a mixed set of components consisting of Teraflex 8-arm Alpine IR adjustable control arms (4.5" lift) and front track bar, Rock Krawler Diesel Coils, Arizona Desert Racing adjustable shocks, 17x9.5 Black Rhino wheels and Toyo Open Country RT tires.
 

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