Minimum Coolant in Reservoir... Again

[iklo]

The level will change based on the ambient temperature. Check it again when the engine is cold and when the ambient temp is the same as when you last filled it in.

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[Hostile17]

I have the same issue. Dealer did pressure test and found nothing. Sits at that MIN line at all times.

Interesting- even after you fill it up to Max?

 

[Hostile17]

The level will change based on the ambient temperature. Check it again when the engine is cold and when the ambient temp is the same as when you last filled it in.

Well that's the issue I'm worried about. It was below min, so I filled to max three days ago. I checked it this morning completely cold and it was back down just under the minimum line again...

 

[Will]

One more piece of low hanging fruit is check that the engine oil cooler is not cracked.
Climb up on top of the engine bay and point a flashlight down in the engine valley next to the oil filter housing. The filler housing is part of the engine oil cooler. The oil coolers are known to crack and leak. Service techs over-tighten the oil filters all the time and it’s also a plastic part in an area that stays really hot. Mine was cracked and I could see a good bit of oil and coolant pooled in the engine valley. I could not believe that this amount of fluid never made it down the side of the block or hit the floor.
I had the engine oil cooler replaced and then developed a couple of coolant hose leaks: one near the EGR cooler and one below the radiator. I found those by using the coolant dye.
I replaced the factory spring clamps with worm drive clamps and that fixed those issues.
I have left the dye in the coolant now for 3 months because it has developed a sweet odor on start up after it has sat cold for a day or two. It does not have an odor or visible leaks that I can find when she sits. The smell is only on startup so that makes me think that it’s burning off somewhere. I changed the spark plugs at the same time as the oil cooler, scoped the cylinders and did not see any signs of wash.
So I’m stumped. Sorry to hi jack the thread but thought I would share my experience with chasing coolant.

2018 JLUR 3.6L 95K miles

Here’s some picks of the leak I found with the dye:

 

[WhereRU_A-A-Ron]

Well that's the issue I'm worried about. It was below min, so I filled to max three days ago. I checked it this morning completely cold and it was back down just under the minimum line again...

Did you fill it to MAX when the motor was hot? If so, it's definitely going to drop from that level once the system has cooled down.

 

[Hostile17]

One more piece of low hanging fruit is check that the engine oil cooler is not cracked.
Climb up on top of the engine bay and point a flashlight down in the engine valley next to the oil filter housing. The filler housing is part of the engine oil cooler. The oil coolers are known to crack and leak. Service techs over-tighten the oil filters all the time and it’s also a plastic part in an area that stays really hot. Mine was cracked and I could see a good bit of oil and coolant pooled in the engine valley. I could not believe that this amount of fluid never made it down the side of the block or hit the floor.
I had the engine oil cooler replaced and then developed a couple of coolant hose leaks: one near the EGR cooler and one below the radiator. I found those by using the coolant dye.
I replaced the factory spring clamps with worm drive clamps and that fixed those issues.
I have left the dye in the coolant now for 3 months because it has developed a sweet odor on start up after it has sat cold for a day or two. It does not have an odor or visible leaks that I can find when she sits. The smell is only on startup so that makes me think that it’s burning off somewhere. I changed the spark plugs at the same time as the oil cooler, scoped the cylinders and did not see any signs of wash.
So I’m stumped. Sorry to hi jack the thread but thought I would share my experience with chasing coolant.

2018 JLUR 3.6L 95K miles

Here’s some picks of the leak I found with the dye:

Thank you! I'll take a look at this too! I appreciate the suggestions!

Were you having the same issue where the reservoir would be low after topping off? Or what made you realize you had to do some diagnostic work to identify a leak?

 

[Hostile17]

Did you fill it to MAX when the motor was hot? If so, it's definitely going to drop from that level once the system has cooled down.

Well I ran it after the oil change for about 40 seconds? I was always taught to do that after an oil change and check the levels. I don't know that it really matters because I know thing takes 5 qts and I put in 5 qts but it's still part of my SOP lol

Do you think the motor could have gotten that hot within such a short period to where it would affect the coolant that much?

 

[WhereRU_A-A-Ron]

Well I ran it after the oil change for about 40 seconds? I was always taught to do that after an oil change and check the levels. I don't know that it really matters because I know thing takes 5 qts and I put in 5 qts but it's still part of my SOP lol

Do you think the motor could have gotten that hot within such a short period to where it would affect the coolant that much?

I doubt running it for that long would've made much, if any, difference at all.

I guess what I'm really trying to get at is (and maybe you are already doing this so I'm not assuming you aren't) make sure you're evaluating the coolant level at the same cooling system state every time.

 

[Will]

The owner's manual wants you to only open the reservoir cap only after the engine is COMPLETELY cooled. I do my best to follow that. Always open it slowly to release the pressure before it pushes fluid out.

Yes, I had the same issue as you. About once a month I would be at or below the minimum line when cooled and I topped it off to the max line 4 or 5 times over the coarse of 6 months. I used distilled water the first couple of times and then got some of the premixed coolant to top it off with the last couple of times.

When I had the oil cooler replaced, the tech, who is a good friend, replaced all of the coolant at that time.

Make sure you're always checking the coolant level when its fully cooled and fully warmed up as others have suggested.

In my case I was absolutely losing coolant.

 

[Hostile17]

Thank you everyone! These are really good notes And I'm going to start logging the levels at both completely cooled in the morning before I start it and check it when it's warmed up too just to kind of set baselines.

The coolant came really quick from Amazon so I just filled it up to the max line and ran it for about 18 minutes To see where it sat, which was about a 1/4 inch higher. With those established I'll continue checking it regularly and if I'm seeing the issue of it going back down like Will posted about, then I know there needs to be full investigation.

Meanwhile since I was already in there I did try and check around the oil filter housing in the engine valley and I didn't really see anything pooling. I did see a bit of old oil buildup, which I imagine is from dripping when taking out the filter? I tried taking some photos but can't say they're really great LOL

 

[WhereRU_A-A-Ron]

Looks good to me. I don't see any evidence of an oil leak there at all. Let us know if you see a wild swing in coolant level.

 

[Hostile17]

Looks good to me. I don't see any evidence of an oil leak there at all. Let us know if you see a wild swing in coolant level.

Will do! Thank you guys again!

 

[Jebiruph]

Was there not any any build up or signs outside of it showing in the UV light?

It was hard to find without the UV light.

 

[SadRobot]

Mine was doing this for a while. Every time I did an oil change (every 3 months) I was losing coolant. One day it dropped a whole lot. Like half below the MIN level. Turns out my coolant was going into my cylinders and the head gasket had blown.

That's worse case scenario though. I finally got it diagnosed by a shop and there were misfires happening and once they got a camera down in there that's where the coolant had gone.

Keep us posted what you find!

 

[Hostile17]

Mine was doing this for a while. Every time I did an oil change (every 3 months) I was losing coolant. One day it dropped a whole lot. Like half below the MIN level. Turns out my coolant was going into my cylinders and the head gasket had blown.

That's worse case scenario though. I finally got it diagnosed by a shop and there were misfires happening and once they got a camera down in there that's where the coolant had gone.

Keep us posted what you find!

Dang that is definitely where my mind immediately jumped this morning. I hope that's not the case. I don't run this thing hard and considering the low miles I sure hope the head gasket hasn't gone! I haven't gotten any codes in the scan I did with jscan didn't show anything either as far as misfires... Really hoping it stays at max and it was just some weird giant air pocket hah

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