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Lowered my JL 3.6L Coolant Operating Temp

SavannahAL

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My 2018 JL was purchased on 20 August 2018, factory new with 18 miles. During my 36,000 miles warranty I had it to the two different Jeep dealers 4 times with the complaint that the coolant was boiling in the overflow reservoir and/or sometimes my reservoir was dry. Jeep added 16-32 ounces of coolant on 3 of the 4 visits.
My normal operating temp was 205 to 235, whether summer or winter. My highest temp's occurred when in stop-n-go traffic and on the Interstate in West Virginia traveling WV mountains. No towing was involved.

Jeep replaced my overflow reservoir and some of the tube (or tubing?) associated with the reservoir and stated they could not duplicate the problem of overheating and always circled back to "it didn't throw a code." Several times I was stuck at an Interstate rest stop until the JL cooled down enough to proceed. I also had the distinct smell of coolant inside the cabin

Now the good news that may be helpful to other JL owners who have asked about larger cooling fans.
Myself and my buddies are all retired for many years now. While at bear camp in Dec 2020 my Wrangler problem came up. One guy was a mechanic for 4 years then a service manager for another 42 years, mostly at Ford dealerships. He suspected a head gasket problem and stated they don't always throw codes with pin-prick leaks.

He recommended K-Seal Ultimate Permanent Head Gasket Repair, about 20 bucks. I was out-of-warranty so I bought a 16oz bottle. While at my son's we disconnected the upper radiator hose and used a flex tube funnel and poured it in. A small amount went on the driveway, but not much.

The difference was immediate and pronounced. On the trip home using the menu for digital coolant temp I was running 185 to 205f. My Wrangler never ran that cool. Also, my gas miles went up between 1.5 to 1.7mpg with the engine not running so hot. It has been about 100 days and I'm still seeing the same results.

A long story but much has been written from the few who seem to have hot running Jeeps. Just last month I towed a 1,500lb John Deere compact tractor on a 400lb trailer from Leesburg, VA to Radford, VA. About 4-1/2 hours without issue. Before I wouldn't attempt to tow anything.

My personal experience in the hope it may help some of you.
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DudeBro

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I'd still get the engine repaired, It shouldn't have a head gasket leak. Since you have documentation showing that you've been trying to get it fixed while under warranty it should still be covered even if it's now past warranty. That head gasket fix stuff is only meant to be a temporary fix until you can get the head gasket replaced. I know they say permanent on the bottle, but it's really just a bandaid fix.
 
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SavannahAL

SavannahAL

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I'd still get the engine repaired, It shouldn't have a head gasket leak. Since you have documentation showing that you've been trying to get it fixed while under warranty it should still be covered even if it's now past warranty. That head gasket fix stuff is only meant to be a temporary fix until you can get the head gasket replaced. I know they say permanent on the bottle, but it's really just a bandaid fix.
I agree with you. I dealt with two service departments in the Savannah area and was not impressed. Techs would leave after 3 to6 months and then I'd be dealing with a different tech. It has been a frustrating journey. I recently moved to southwest Virginia and the closest Jeep dealer is in Chrisitiansburg about an hour northeast of me. Overall the Jeep has been great as a hunting vehicle.
 

rrubbee

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It would appear to me that with a gasket leak you would not be maintaining pressure in the cooling system thus you would run hot and overheat. You need to maintain the pressure to keep cool. When you sealed the leak in the gasket....the pressure was maintained and it ran cooler. What I do not understand is why the mechanic was not able to detect a leak (keep the system pressurized over night and see if a pressure gauge went down). Sounds like someone dropped the ball on this one.
IMHO

Abe
 

mwilk012

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It would appear to me that with a gasket leak you would not be maintaining pressure in the cooling system thus you would run hot and overheat. You need to maintain the pressure to keep cool. When you sealed the leak in the gasket....the pressure was maintained and it ran cooler. What I do not understand is why the mechanic was not able to detect a leak (keep the system pressurized over night and see if a pressure gauge went down). Sounds like someone dropped the ball on this one.
IMHO

Abe
Over that amount of time with a small leak, it would be impossible to differentiate between a leak and something else as subtle as a change in ambient temperature.
 

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SavannahAL

SavannahAL

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It would appear to me that with a gasket leak you would not be maintaining pressure in the cooling system thus you would run hot and overheat. You need to maintain the pressure to keep cool. When you sealed the leak in the gasket....the pressure was maintained and it ran cooler. What I do not understand is why the mechanic was not able to detect a leak (keep the system pressurized over night and see if a pressure gauge went down). Sounds like someone dropped the ball on this one.
IMHO

Abe
Abe, that makes sense to me. What I know is the two Jeep dealers (one owner) in Savannah have a lot of turnover in mechanics. A mechanic that was both knowledgeable and motivated could of/should of gotten to the bottom of the issue.
 

wibornz

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One of the Jeeps that travel all over the country with us runs way hotter than all the others. His Jeep is usually 15 to 20 degrees hotter than the other Jeeps in basically all situations. He has been trying to figure this out for 2 years. The dealerships have not been any help. He will see temps as high as 250 degrees while towing his camper in the hills. He also gets about 2 miles to the gallon less in fuel mileage. I am forwarding this to him.
 
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SavannahAL

SavannahAL

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One of the Jeeps that travel all over the country with us runs way hotter than all the others. His Jeep is usually 15 to 20 degrees hotter than the other Jeeps in basically all situations. He has been trying to figure this out for 2 years. The dealerships have not been any help. He will see temps as high as 250 degrees while towing his camper in the hills. He also gets about 2 miles to the gallon less in fuel mileage. I am forwarding this to him.
I hope it helps him If he decides to try it. You may want to post the results. I acknowledge this is not the best way/optimal way, but I was a little desperate and a lot frustrated so I tried it. In my case at least so far I have a better running Jeep.
 

wibornz

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I hope it helps him If he decides to try it. You may want to post the results. I acknowledge this is not the best way/optimal way, but I was a little desperate and a lot frustrated so I tried it. In my case at least so far I have a better running Jeep.
I forward the text from your post. I will let you know what he does and how it works out.
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