Unexplained Coolant Loss

[Byrds8]

Since I am waiting to take it to the dealer until I can get the oil tested, I went ahead and put more coolant in it. This time though I paid attention to how much was missing out of the jug of coolant. Since we purchased the Jeeps last Sept, I have used a quart of coolant. I believe I only put a few oz in hers once since we got it. The rest went into mine. Mine has just under 21K miles on it, hers has 8,659. If I guessed the amount I put in hers to be 4oz, Id still think 28oz in 21K miles is excessive for sure.

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[CarbonSteel]

@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?

Yes, it will. A coolant leak in the engine will always find its way into the oil. I would pull a sample without changing the oil. Easy to do, just have to loosen the drain plug carefully and throttle the flow with it, then tighten it back. I became a pro at it on my 3.6L.

I posted this one in another thread, but look at the potassium levels starting at 50K. The oil leak itself became apparent at about 65K or so, but the coolant had been leaking long before that. I sold it before I could positively confirm it was only the oil cooler leaking by doing more UOAs, but something in me says it was a head gasket or cracked head/block.

The miles per PPM of potassium was still dropping (should have been increasing to the point of the total oil change miles meaning that zero potassium was in the oil) and though it takes a few oil changes to flush it all out, I did one OC without testing as a flush and the numbers had not really improved. The compression ratio combined with the operating temperatures of the 3.6L is a perfect recipe for a leaking head gasket or a cracked head/block.

 

[Byrds8]

Yes, it will. A coolant leak in the engine will always find its way into the oil. I would pull a sample without changing the oil. Easy to do, just have to loosen the drain plug carefully and throttle the flow with it, then tighten it back. I became a pro at it on my 3.6L.

I posted this one in another thread, but look at the potassium levels starting at 50K. The oil leak itself became apparent at about 65K or so, but the coolant had been leaking long before that. I sold it before I could positively confirm it was only the oil cooler leaking by doing more UOAs, but something in me says it was a head gasket or cracked head/block.

The miles per PPM of potassium was still dropping (should have been increasing to the point of the total oil change miles meaning that zero potassium was in the oil) and though it takes a few oil changes to flush it all out, I did one OC without testing as a flush and the numbers had not really improved. The compression ratio combined with the operating temperatures of the 3.6L is a perfect recipe for a leaking head gasket or a cracked head/block.

Howd you go about doing it before an oil change? Looking at their site, it says do the catch half way through? Or did you just let half drain out and fill it back up etc?

I have done four oil changes so far in mine. All with Pennzoil Plat.

 

[CarbonSteel]

Howd you go about doing it before an oil change? Looking at their site, it says do the catch half way through? Or did you just let half drain out and fill it back up etc?

I have done four oil changes so far in mine. All with Pennzoil Plat.

For the purposes of this test, it does not matter and honestly, I have done more than 40 UOAs and the point at which you catch the oil is irrelevant. They say that to attempt to be consistent, but it just does not matter. If there is metal that has settled in the pan, I want to know the "full amount" of metal and not just what may be caught in suspension.

In your case, you want to confirm/deny the presence of potassium and ideally, it should be zero, and there can be variations due to additives in the oil, but more than 3PPM is a yellow flag and more than 5PPM is a red flag.

 

[Byrds8]

For the purposes of this test, it does not matter and honestly, I have done more than 40 UOAs and the point at which you catch the oil is irrelevant. They say that to attempt to be consistent, but it just does not matter. If there is metal that has settled in the pan, I want to know the "full amount" of metal and not just what may be caught in suspension.

In your case, you want to confirm/deny the presence of potassium and ideally, it should be zero, but there can be variations due to additives in the oil, but more than 3PPM is a yellow flag and more than 5PPM is a red flag.

Copy that. I ordered the tests already so Ill see about doing it next weekend. Guess I should have waited then on filling up the coolant. I may just have to go an hour down the road to a different dealership to get them to look at it. Maybe they would be better than my local one. Even the sales guy that we purchased the vehicle from says he wouldn't trust them to change his oil lol. He mentioned that last night when I had half a moment of thinking to swap to a Gladiator.

 

[Steph1]

JLs like to keep the coolant at the seam. You can put more but the jeep will just spit it out. Leave it at the seam and it will/should stay there.

 

[CarbonSteel]

Copy that. I ordered the tests already so Ill see about doing it next weekend. Guess I should have waited then on filling up the coolant. I may just have to go an hour down the road to a different dealership to get them to look at it. Maybe they would be better than my local one. Even the sales guy that we purchased the vehicle from says he wouldn't trust them to change his oil lol. He mentioned that last night when I had half a moment of thinking to swap to a Gladiator.

Refilling or not refilling the coolant won't matter with regards to the test, but obviously you do not want it to go low. If there is an internal leak, you will see it in the oil test. Bear in mind that if (for example) your potassium is 7-10PPM there is no standard test that will detect that (depending on the mileage on the oil at the time of the test and the amount of potassium detected). This is just an "early distant warning" to allow you to get ahead of it and plan the repairs before it becomes critical.

 

[Byrds8]

Refilling or not refilling the coolant won't matter with regards to the test, but obviously you do not want it to go low. If there is an internal leak, you will see it in the oil test. Bear in mind that if (for example) your potassium is 7-10PPM there is no standard test that will detect that (depending on the mileage on the oil at the time of the test and the amount of potassium detected). This is just an "early distant warning" to allow you to get ahead of it and plan the repairs before it becomes critical.

Refilling it was simply due to the local dealer saying let it run low before bringing back to them. I had filled it back up last time when I took it to them.

 

[Byrds8]

So, after all this time and taking it to the dealer to "fix" the coolant loss issue, I think I may have finally found it. I still kept having the lost and still would find white residue on places underneath the reservoir. Today, I noticed white crusty crap in the threads of the cap and the tank. Cleaned it up and tightened it on and ran it til hot. Soon as I turned it off, you could hear air coming from it. Wiggling it around a bit caused a lot more air. So I waited for it to cool, and stole my wife's cap off hers. Now no more air pouring out. So Ill get with the dealership tomorrow about getting a new cap and see how that goes. Hopefully it puts this to bed once and for all.

 

[Yawnie'sPapa]

So, after all this time and taking it to the dealer to "fix" the coolant loss issue, I think I may have finally found it. I still kept having the lost and still would find white residue on places underneath the reservoir. Today, I noticed white crusty crap in the threads of the cap and the tank. Cleaned it up and tightened it on and ran it til hot. Soon as I turned it off, you could hear air coming from it. Wiggling it around a bit caused a lot more air. So I waited for it to cool, and stole my wife's cap off hers. Now no more air pouring out. So Ill get with the dealership tomorrow about getting a new cap and see how that goes. Hopefully it puts this to bed once and for all.

That cap should hold pressure. I used to see that a lot in the old days with brass radiators and metal pressure caps - loss of fluid (and sometimes over-heating)
Replacing the cap almost always solved the issue.
I believe these are supposed to hold around 16 psi.

 

[Byrds8]

That cap should hold pressure. I used to see that a lot in the old days with brass radiators and metal pressure caps - loss of fluid (and sometimes over-heating)
Replacing the cap almost always solved the issue.
I believe these are supposed to hold around 16 psi.

These are 21 PSI. Yeah I was surprised when I actually heard the air coming out. Never had an issue with overheating just loss of coolant.

 

[Yzfguy]

Just found this thread after picking mine up from the dealer last week. Same symptoms and they did a pressure test, said it's fine and must have been a "fluke." Not a great feeling.

 

[Byrds8]

Just found this thread after picking mine up from the dealer last week. Same symptoms and they did a pressure test, said it's fine and must have been a "fluke." Not a great feeling.

That is what they said about mine also. Then I took it back and said look under the tank, there is residue everywhere. So they said they replaced the hose. Don’t think they did though. When they do a pressure test, isn’t the normal cap off?

 

[Yzfguy]

That is what they said about mine also. Then I took it back and said look under the tank, there is residue everywhere. So they said they replaced the hose. Don’t think they did though. When they do a pressure test, isn’t the normal cap off?

I don't trust much that my dealer does. I had an appointment, a month and a half I had to wait, and dropped it off only to wait 4 days for them to "have time" to look at it. Then after I called to bitch, they supposedly did a pressure test and no work was needed.
I love this jeep, but the dealer is making me doubt I'd ever buy another. I actually have a knot in my stomach the whole time they have it, and now nothing was even done. I will have to check the level daily and keep on it I suppose.

 

[Byrds8]

I don't trust much that my dealer does. I had an appointment, a month and a half I had to wait, and dropped it off only to wait 4 days for them to "have time" to look at it. Then after I called to bitch, they supposedly did a pressure test and no work was needed.
I love this jeep, but the dealer is making me doubt I'd ever buy another. I actually have a knot in my stomach the whole time they have it, and now nothing was even done. I will have to check the level daily and keep on it I suppose.

yeah the dealerships suck. Look all around the engine bay and crawl under it and see if you can find residue. Check the cap etc. maybe you can figure it out yourself.

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