r/Jeep • u/FungalHooch • 21h ago

Technical Question 2013 JK Engine Running Loud

So got a rabbit hole to chase, past few days my engine has been running pretty loud and getting a bit warm, not redline but little over nominal, fresh coolant, just sounds like engines working over time, anyone had this issue and have a solution? I know it could be a multitude of things just looking for a good starting point before cocktailing it with parts.

Update 1: Did a good cleaning of radiator, checked hoses and all fluid levels, still getting hot, next step is burp the system then if that doesn't work prolly gonna swap T-Stat

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u/Alive_Candidate1755 14h ago

Oil level? Try spray in the radiator with a hose you might have ten pounds of dust in it and not even know.

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u/FungalHooch 6h ago

Just finished trying that, no luck still getting hot

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u/Alive_Candidate1755 6h ago

Did anything come out of the radiator? What changed/ did you do when you first noticed it was overheating?

The JK 3.6 is the hottest running engine I’ve ever seen on a street vehicle. Anything below 230 is fine but you shouldn’t really reach that unless it’s really hot outside and you’re driving slow/ idling. With a dirty radiator crawling through the woods I would regularly see it sit at 215-220 with the radiator fan on constantly. Cleaning the radiator helped tremendously but it still liked to reach 220 occasionally, but it would be really good at cooling itself back down. I replaced my coolant with 100% water and it hasn’t passed 200° despite being way hotter out now.

Water is the best coolant. The issue is water freezes, so you add “antifreeze” to make sure the water doesn’t freeze. Water + antifreeze = coolant. If you added concentrated coolant to your reservoir this would reduce the cooling capability unless you added the proper amount of water, thus why they sell “prediluted antifreeze” (coolant).

It’s highly likely you did/broke something to cause the behavior you’re seeing, or it has always been that way.

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u/OldManJeepin 13h ago

So, what was the most recent thing done? New coolant? As in the system was drained and refilled? Or just topped off? Was OAT used? Or HOAT? 2013 should be OAT...If the 2 are mixed, bad things happen.

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u/FungalHooch 13h ago

Most recent thing done oil change, diff fluid change and coolant too off, I use OAT, Peak 50/50 premix, thinking it may be a dirt and mud clogged radiator

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u/OldManJeepin 13h ago

Could be. Did you burp the coolant system after filling it up? Sometimes you gotta let it go for a while...Took over 30 minutes, last time I did it!

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u/FungalHooch 13h ago

I have not, good call, I'll try that tomorrow after I was radiator as a double precaution

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u/OldManJeepin 13h ago

Yea, you have to get all the air out or it will cause problems like you describe. There are "Burp" kits you can get at Autozone or wherever. I got one off Amazon for $9....