2015 Jeep Wrangler Overheating Issue

I just purchased a 2015 that began overheating on my way home from the lot. We have been chasing down this issue for 4 weeks now. The overflow tank is staying full and having to add coolant to rad about every 2 days, unless I've put on some miles. There is residue in the drivers side pocket where the windshield wiper spray nozzle is and I'm often seeing spray or residue on my windshield and hood after driving a lot.

A mechanic has done a full flush of the system (I have not verified type of coolant they used to fill back up), we have done our own separate heater core flush after they did the whole thing, have replaced rad cap and thermostat. Each "fix" seems to make it a little bit better for longer periods of time, but not for more than a few days at best.

When the temps start to rise over about 226-230°, heater blows hand-burning hot...then a little less hot, then warm, then a little cool. And it does this in a cycle of sorts.

We are extremely frustrated and no one can find the issue. Next step is replace rad I guess?
 
NineLives said:
I just purchased a 2015 that began overheating on my way home from the lot. We have been chasing down this issue for 4 weeks now. The overflow tank is staying full and having to add coolant to rad about every 2 days, unless I've put on some miles. There is residue in the drivers side pocket where the windshield wiper spray nozzle is and I'm often seeing spray or residue on my windshield and hood after driving a lot.

A mechanic has done a full flush of the system (I have not verified type of coolant they used to fill back up), we have done our own separate heater core flush after they did the whole thing, have replaced rad cap and thermostat. Each "fix" seems to make it a little bit better for longer periods of time, but not for more than a few days at best.

When the temps start to rise over about 226-230°, heater blows hand-burning hot...then a little less hot, then warm, then a little cool. And it does this in a cycle of sorts.

We are extremely frustrated and no one can find the issue. Next step is replace rad I guess?
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I know a lot of used cars are sold ”as-is” but many dealers will work with people when something like this happens. Have you contacted the dealer? Don’t just toss parts at it, has anyone done a pressure test on it?
 
Danarch said:
I know a lot of used cars are sold ”as-is” but many dealers will work with people when something like this happens. Have you contacted the dealer? Don’t just toss parts at it, has anyone done a pressure test on it?
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Hi, thanks! I'm not able to work with the dealer (not going into reasons). The shop who did the initial flush after purchase did a pressure test before flushing. No issues, held pressure fine.
 
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NineLives said:
Hi, thanks! I'm not able to work with the dealer (not going into reasons). The shop who did the initial flush after purchase did a pressure test before flushing. No issues, held pressure fine.
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Was the air burped out of the system, raising the front up is the easiest way with it running and cap off.
 
Anybodyhome said:
That sounds like air in the system. Is the temp gauge moving with the air temp changes?
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The digital reading is all over the place, fluctuating 20 degrees or more in seconds. I'm really leaning toward air in the system myself, and I've heard how difficult it can be to completely burp it.


With regards to a rad cap.... I purchased a new one from Autozone that is 18lbs. I look at Mopar and OEM is 17lbs. Does this matter? I'm not sure I've got my old cap to compare the 2.
 
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NineLives said:
Hi, sorry for the late reply. I didnt bookmark the page and lost this discussion!

I cannot say for certain it was burped...properly..? We are going to do this ourselves this weekend after getting a coolant funnel kit.
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Just raise the front of the Jeep up about 6 to 8" with the cap off and engine idling.
 
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NineLives said:
Hi, sorry for the late reply. I didnt bookmark the page and lost this discussion!

I cannot say for certain it was burped...properly..? We are going to do this ourselves this weekend after getting a coolant funnel kit.
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You don't need any special funnel; you probably already have one somewhere in the garage.
If you have issue raising the front end, here's an idea:
Drive your Jeep to the nearest parking lot that has the concrete parking space curbs. Take a spotter with you.

1666878122034.png

Get the front wheels of your JK on top of the curb and turn the engine off. Let it set just for a few and remove the radiator cap.
Restart the engine. (I never recommend removing the radiator cap while the engine is running).
As the engine idles, add coolant. The radiator will burp air out the cap after you've poured, so keep your hands away between pours.
Once the radiator is full and it's run for a few minutes without any air burps at the cap, kill the engine and replace the radiator cap.
Start the engine and check you temp gauge for correct running temp and take it for a spin to make sure it stays within the acceptable range without bouncing all over the place.
 
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Anybodyhome said:
You don't need any special funnel; you probably already have one somewhere in the garage.
If you have issue raising the front end, here's an idea:
Drive your Jeep to the nearest parking lot that has the concrete parking space curbs. Take a spotter with you.

View attachment 122795
Get the front wheels of your JK on top of the curb and turn the engine off. Let it set just for a few and remove the radiator cap.
Restart the engine. (I never recommend removing the radiator cap while the engine is running).
As the engine idles, add coolant. The radiator will burp air out the cap after you've poured, so keep your hands away between pours.
Once the radiator is full and it's run for a few minutes without any air burps at the cap, kill the engine and replace the radiator cap.
Start the engine and check you temp gauge for correct running temp and take it for a spin to make sure it stays within the acceptable range without bouncing all over the place.
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I will do this when I get home. My driveway is steep. Thank you!
 
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Ok..

-Jacked up front end, removed cap.

- used coolant overflow funnel kit thing and have good seal (or so I thought at the time)

- started engine. Added 50/50 gradually. Air bubbles galore.

- squeezed upper hose , more bubbles. Eventually they stop.

- check hoses. Upper never getting warm or hot, temp on dash at 213 at this point. Heater hose very hot.

- still have some fluid in funnel, thought it would be a good idea to rev engine.


- not a good idea! Coolant begins rising in the funnel to the point of overflow. Shut off engine.


-about 3-5mins the funnel starts dropping. I notice it is a little wobbly. I check the cap and it has lost some of the tightness. Plugged the funnel and removed it, retightened cap and adapter and reinserted plugged funnel. Maybe 3oz of fluid in funnel.

- restart, add fluid and there's briefly some bubbles. Added just a touch more. Suddenly level starts to rise rapidly in funnel and spills over before i can shut it off.

-within a minute of engine off the funnel nearly depletes

-tried this one more time with same results, and now the funnel is empty. *Car has not running.

-overflow has been full (way too full) the whole process. Currently it is at the level about where the blowout spout is in the back of the bottle, a few inches above MAX.


What next?
 
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I've not had the experience, but it sounds like the radiator may be partially blocked.
NineLives said:
check hoses. Upper never getting warm or hot, temp on dash at 213 at this point. Heater hose very hot.
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Are you getting flow thru the upper hose at this point? Here's another thought if the upper hose is not getting hot- the t-stat is stuck open. If you shut the engine off and let it cool, then fire it up a few hours later, put your hand around the upper hose to see if you're getting flow thru the hose as soon as you start the engine. If so, the t-stat is stuck open.

NineLives said:
about 3-5mins the funnel starts dropping. I notice it is a little wobbly. I check the cap and it has lost some of the tightness. Plugged the funnel and removed it, retightened cap and adapter and reinserted plugged funnel. Maybe 3oz of fluid in funnel.

- restart, add fluid and there's briefly some bubbles. Added just a touch more. Suddenly level starts to rise rapidly in funnel and spills over before i can shut it off.

-within a minute of engine off the funnel nearly depletes
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I've not used one of those funnels. I remove the cap altogether and use a regular funnel, fill to top and let coolant settle and burp, like a cup or 2 at a time. It took me a little while, but when the last burp occurred and I filled radiator with no further settling, I knew I was good.
 
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I have never used the funnel system you're talking about. Just a regular old funnel, like @Anybodyhome. But it does sound as if you've got something blocked. I'd start with the thermostat, but it could also be in the radiator or (I hope not...) in the block.
 
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Anybodyhome said:
I've not had the experience, but it sounds like the radiator may be partially blocked.

Are you getting flow thru the upper hose at this point? Here's another thought if the upper hose is not getting hot- the t-stat is stuck open. If you shut the engine off and let it cool, then fire it up a few hours later, put your hand around the upper hose to see if you're getting flow thru the hose as soon as you start the engine. If so, the t-stat is stuck open.


I've not used one of those funnels. I remove the cap altogether and use a regular funnel, fill to top and let coolant settle and burp, like a cup or 2 at a time. It took me a little while, but when the last burp occurred and I filled radiator with no further settling, I knew I was good.
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But did the cooolant ever erupt back up out the radiator? Special funnel or not, why did the fluid rapidly rise with engine idling for me?
Dirty Dog said:
I have never used the funnel system you're talking about. Just a regular old funnel, like @Anybodyhome. But it does sound as if you've got something blocked. I'd start with the thermostat, but it could also be in the radiator or (I hope not...) in the block.
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Had my oil changed yesterday by same shop that did the flush (that I stated I'd had done in my initial comment) and they said no residue/milkyness in the oil drained. So hopefully that rules out the block.
 
So I've put about 250 miles on it since I attempted to burp the system last night, covering all sorts of terrain and grades, including some light offroading (this is my job). Mostly stayed around the 210-222 range. Towards end of the day today it began the weird extreme fluctuations - would be at normal op temp and then spike to 228 and inch up in the 230s, then drop back down to 226 or whatever. Or running for a minute around 228 and then spike to 248 (that only happened once) and drop to 235. But mostly.....mostly it ran as expected today.


We are going to burp again tomorrow, and this time I'll have help. I was impatient waiting for my husband to get home last night and just did it myself.


Thank you so much to everyone who has given advice and thank you for allowing the thread to remain open despite me hijacking it. 😊
 
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NineLives said:
Had my oil changed yesterday by same shop that did the flush (that I stated I'd had done in my initial comment) and they said no residue/milkyness in the oil drained. So hopefully that rules out the block.
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That means it's unlikely that the block is cracked. But it doesn't mean it wasn't cracked and someone did a rotten job trying to repair it, blocking one or more water passages in the process.
I'd still start with the thermostat though. It's far more common.
 
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