Unexplained Coolant Loss

[Byrds8]

Since I have owned my Wrangler, I keep having to put coolant in it. Last time was about 2 months ago maybe. I usually fill it to between min/max and put more back in it when it drops just below the seam line. Its right at the seam now. I usually put more in about every other month or so. I cannot find any leaks, see nothing hit the ground, there is no smell in the engine bay nor at the exhaust. Anyone have ideas on where the coolant may be going? I took it to the dealer but all they did was a leak test and said its all good.

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[Flip]

I did some research for you; this might help or point you in the right direction. I think #5 could be a likely culprit. Best of luck to you.

1. Test drive your vehicle a short distance and park on level ground. Allow your vehicle to cool down for 5-15 minutes before opening the hood and recheck the coolant level.

2. Check where the overflow attaches to your radiator under the cap. If it's wet there, or you see any traces of seepage, use a zip tie like a hose clamp on that hose.

3. Blow out the coolant line from the radiator to the coolant bottle.

4. Make sure that your radiator is topped off with coolant when cold. If it is not full, top it off, and warm up the engine with the heater on full heat. Then let it cool down and check it once again. The Radiator has to be full of coolant, and free of air, for it to draw coolant back to the radiator at cool down.

5. A tiny leak in a radiator; doesn't pool in the garage after parking it, so it might be evaporating while driving.

Also check this thread to see if there's anything that might help.

(1) Engine coolant level? | Jeep Wrangler Forums (JL / JLU) -- Rubicon, 4xe, 392, Sahara, Sport - JLwranglerforums.com

 

[Byrds8]

I did some research for you; this might help or point you in the right direction. I think #5 could be a likely culprit. Best of luck to you.

1. Test drive your vehicle a short distance and park on level ground. Allow your vehicle to cool down for 5-15 minutes before opening the hood and recheck the coolant level.

2. Check where the overflow attaches to your radiator under the cap. If it's wet there, or you see any traces of seepage, use a zip tie like a hose clamp on that hose.

3. Blow out the coolant line from the radiator to the coolant bottle.

4. Make sure that your radiator is topped off with coolant when cold. If it is not full, top it off, and warm up the engine with the heater on full heat. Then let it cool down and check it once again. The Radiator has to be full of coolant, and free of air, for it to draw coolant back to the radiator at cool down.

5. A tiny leak in a radiator; doesn't pool in the garage after parking it, so it might be evaporating while driving.

Also check this thread to see if there's anything that might help.

(1) Engine coolant level? | Jeep Wrangler Forums (JL / JLU) -- Rubicon, 4xe, 392, Sahara, Sport - JLwranglerforums.com

I thought you were always to check the coolant cold? If I drive it then let it sit it’s higher than if I check it the next morning etc.

Not sure what you mean by number two.

What’s the purpose of number three?

I’ll look into this.

I’d assume if there was a leak, it would be found when they did a pressure test?

 

[Flip]

I thought you were always to check the coolant cold? If I drive it then let it sit it’s higher than if I check it the next morning etc.

Not sure what you mean by number two.

What’s the purpose of number three?

I’ll look into this.

I’d assume if there was a leak, it would be found when they did a pressure test?

For a pressure test, don't they just attach a pump on the radiator, give it a few pumps, see if the pressure holds and call it good? If there is a small leak, under pressure and it is evaporating while driving I don't think that would show up while performing a pressure test, but I could be wrong.

 

[Byrds8]

For a pressure test, don't they just attach a pump on the radiator, give it a few pumps, see if the pressure holds and call it good? If there is a small leak, under pressure and it is evaporating while driving I don't think that would show up while performing a pressure test, but I could be wrong.

I do believe they hook up a pump with gauge to the reservoir tank and then see if it leaks down. Granted, you are correct that if it was small enough it may go unnoticed. However there is also a lack of coolant smell. I let my wife sniff all over the place since she has a super nose lol. I have looked at all the places I could to see if there was any coolant residue.

 

[Flip]

I thought you were always to check the coolant cold? If I drive it then let it sit it’s higher than if I check it the next morning etc.

Not sure what you mean by number two.

What’s the purpose of number three?

I’ll look into this.

I’d assume if there was a leak, it would be found when they did a pressure test?

There won't be any residual coolant leaking if it's evaporated. Good sniffer or not this could be the problem with a very small, tiny, little, leak.

#2. Sometimes the overflow hose leaks, causing a very small amount of fluid to leak. (I actually had this happen to one of my vehicles.)

#3. I thought I read if the coolant line from the radiator to the reservoir is plugged, you may get an inaccurate level in your reservoir tank... Does that sound right?

 

[Byrds8]

There won't be any residual coolant leaking if it's evaporated. Good sniffer or not this could be the problem with a very small, tiny, little, leak.

#2. Sometimes the overflow hose leaks, causing a very small amount of fluid to leak. (I actually had this happen to one of my vehicles.)

#3. I thought I read if the coolant line from the radiator to the reservoir is plugged, you may get an inaccurate level in your reservoir tank... Does that sound right?

I mean residue as it white spots etc from where the coolant was. In past vehicles, coolant would leave behind a white residue if it was leaking. Sometimes may even be the color of the coolant if it is caking up.

Ill double check but didnt really see any.

Ahh understood. Ill look into that also.

 

[Adv_aw8s]

Well mine is at the dealer for the exact same thing. I kept having to add coolant, about a quart every couple thousand miles or so. I have the eco diesel and was worried it was the EGR. I never saw any coolant leaking or spots. We would get the occasional sweet smell. They found that the coolant tank had a small leak somewhere and it was either evaporating or burning off on the motor. So hopefully the coolant tank will be in next week.

 

[Byrds8]

Yeah no smell with mine. My wife has smelled when a kid opened nail polish in his closed closet in his closed room up stairs before lol. Never met another with such a sensitive snout. Makes up for me not having any sense of smell I suppose. Hopefully they get you fixed up. I’ll be messing around with mine a bit tomorrow then I’ll fill it. If it goes from between min/max after that I guess I’ll let it drop below the seam and take it in.

 

[flyer92]

Sorry to hear about your coolant loss, but glad you posted about it, as this is yet another data point on what appears to be a common issue with the 3.6L. While there are numerous threads about it in the forum, there doesn't seem to be a consistent diagnosis. Like many, I took my JL to several dealerships and all of them said the coolant system checked out OK with no leaks. In short, they just chalked it up as another "Jeep thing," which is disappointing because I now feel compelled to carry a jug of coolant with me on long road trips, just in case this damn "Jeep thing" decides to drain my cooling system.

When I brought this up to Stellantis's customer support last year, they also had no idea what I was talking about. However, I pretty much expected that because these are the same people who don't seem to know anything about paint bubbling, windows blowing out, or any of the other numerous "Jeep things" we are all intimately familiar with. At this point, I guess the best thing we can do, is to continue bringing this to the dealership's attention and communicating if/when we get any additional information regarding a potential diagnosis and solution. Sad that our beloved (and costly) Wranglers are rife with so many unexplained gremlins, but suffice to say, this will be my last one, even after decades of CJ/Wrangler ownership. Best of luck with troubleshooting, and please keep us advised if/when you have any additional info.

 

[Yawnie'sPapa]

#3. I thought I read if the coolant line from the radiator to the reservoir is plugged, you may get an inaccurate level in your reservoir tank... Does that sound right?

No. Because that's where the pressure cap is - you'd blow something off of that hose was plugged.

I'm talking Gladiator here -
2020 - added 8 ounces in 2.5 years/27,000 miles
2022 - haven't yet added anything, it's about 1/4" below where it was when I first took delivery but it could be lower than the first check because air has finally been purged out of the system after a few drives. It hasn't dropped in the last few months.
Our Grand Cherokees with the 3.6 - can't recall me adding coolant, maybe dealers did. If I did it would have been only one time a long time ago. We've had several GCs with the 3.6 - never dropped low enough on coolant to worry about (and they shouldn't)

How about taking an oil sample and sending it in - that should show any coolant contamination if there is any. If there is any, it means a coolant leak in the block or heads.
You can burn a very small amount of coolant very slowly a bit at a time and the cats will mask some of the smell. Depends on the leak, where it is, etc.

Our JLU Rubicon is a 2.0 so can't compare coolant use to the 3.6 but should be similar - meaning it shouldn't use much if any over the course of a year.

 

[wanderer]

Had the same issue on my 08 with a 3.8. Bad head gasket. And was covered by Jeep under the lifetime warranty.

 

[CarbonSteel]

@Byrds8 - take an oil sample and send it out to Blackstone and check for potassium. Anything above 3PPM is suspect and typically indicates a coolant leak.

My oil cooler started leaking coolant into the oil at 50K though the oil leak itself was not evident until later. Coolant entering the oil can only come from a few places such as the oil cooler, a head gasket, or a cracked head or block.


https://www.blackstone-labs.com/products/free-test-kits/

 

[Byrds8]

Had the same issue on my 08 with a 3.8. Bad head gasket. And was covered by Jeep under the lifetime warranty.

Too bad I dont have a lifetime but with only 20k on the clock, I figure plenty of time.

 

[Byrds8]

@CarbonSteel Next time I change my oil Ill see about getting a test done. I am at 60% oil life so it may be a few months since I no longer have a commute. If its a head gasket instead of the oil cooler, testing the oil would not show anything correct?

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