When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Stock JK TechBulletin board forum regarding issues with OE (original equipment) components of the Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) such as factory suspension parts, engine, transmission, body parts, interior fixtures and the on-board computer.
the #1 issue is all the crap we put in front of the grill, even down to the aftermarket bumpers. people would be surprised how small obstructions can really alter the airflow into the grill. having had 2 larger than factory radiators, I can say it's so much more about the airflow than it is the cooling capacity. especially on the 3.6L where the air has to get through tranny cooler and ac condenser before it gets to the radiator. lights, bullbars, winches, winch control boxes, they jack up the airflow. heck, even removing the factory air damn below the factory front bumper is changing things. the engine just runs hotter by design, but then we go fiddling with things and we make it less optimal.
Originally Posted by a64pilot
I’m very new to this engine having just bought my new to me used Jeep but if we are dumping that much heat into the heads as we have overhead cams there are or will be I think valve train issues and if we don’t run good oil and are diligent about changing it we may get both sludging and maybe coking in the heads, coking less likely, but I’m going to shorten my oil change interval over the recommendation by a lot myself.
can't agree more with this right here. you are on the right track. i changed to 5W30 oil. I can't prove it, but i also hypothesize that I've had issues with high-mileage oil so I've been sticking with just a quality regular 5W30. with ~130k miles on my '13, absolutely zero signs of any sludge issue at all, but i fully believe this heat and oil thinking are the reason for the rocker bearing issues we see.....leading to the tick.
i would run either a good Diesel oil or a better synthetic, but here’s the thing majority of syn oil hasn’t been syn since Castrol found a way to refine Dino oil better and started calling it Syn.
Mobil-1 complained, but lost as Castrol could sell what they called syn for half what Mobil-1 could they had no choice but to sell the “fake”* syn oil too.
Lawyers redefined the definition of Synthetic I guess like they redefined what the word is, is.
Best explanation I found in a quick search, this all went down 25 years ago
I would not run regular oil, look at the temp chart in the below link to see why. I don’t know what our oil temp is, but as it’s cooled by our engine coolant it has to be higher than our coolant temp is, and that’s I think pretty high.
Amsoil I think may be real syn not sure. I plan on using Mobil -1 “extended performance” 5W-30 myself as it has a higher percentage of PAO than regular Mobil-1 and it’s widely available and not too pricey, I will change it at 5,000 miles, why 5,000? Because it’s an easy number to track more than anything else.
PAO oils is commonly considered to be the “real” syn oil that’s used in Automobiles, I don’t believe it’s ever used pure but higher percentages of it is generally considered better especially for high temp conditions like racing, turbos etc.
I am currently trying to understand how my 2015 JKU ran half temp or less for 2 years and now after replacing my thermostat it runs just above half way point or higher at 45-55 mph and when I accelerate to highway speeds it goes up past the 3/4 mark and from my understanding that's like 250+ !! I'm pretty frustrated. Changed thermostat but didn't use OEM.. could be problem but I'm not sure yet. Just changed ECT sensor to see if maybe that was giving a faulty signal some how..but no change after replacing. I have also NEVER had my fan kick on for more then a minute before and that's sitting at drive through. Now the fan runs constantly and is always in it's high speed mode. Somebody hadta have had this issue before so if any of you read this and know how to correct this please share because I'm very sad about it and tired of dumping money into the wrong things. I do plan on trying the OEM thermostat as a last resort. It's 98 bucks compared to the 26 dollar one I put in it. Not sure the accuracy of this image but seems legit
Do you still have the original T stat? If so put it back in, see if that helps. But before you do anything try bleeding the system again, trapped air can cavitate the pump and cause high temps and it’s too easy not to eliminate as an issue.
As a general rule of mechanicing, if you do something and don’t like the result, undo it, or said another way if trouble shooting only change one thing at a time, if you change multiple things and something happened, which thing you changed was the cause?
Another data point for anyone who suspects coolant boiling.
50/50 coolant boils at 220F at atmospheric pressure, every 1 psi of pressure raises the boiling point by 3 degF, so an 18 lb cap raises the boiling point by 54 degrees, add that to 220 and you get 274 degrees of course, so you see the huge effect that a weak cap can have.
Of course know that your coolant gauge reads average coolant temp, and it’s very likely the engine has hot spots of course so you can get coolant boil at lower than 274 degrees on the gauge, because it’s boiling at one of the hot spots
09-12-2024, 11:55 AM
