Did the hood vents being opened help any? I've been considering doing this mod.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.