Coolant unexplained loss.

[Classy Comanche]

So I have had my my cooling system converted. Aluminum Mac tank with a plastic overflow catch tank equipped. Cools great! However I have noticed as I drive the coolant is spit out into the catch tank when warm. Normal and should do so. But I let it cool down for say 6 hours and go back to check. The coolant level inside the catch tank is way lower than it originally was. It's not overheating. I can place my hand on top of the block and hold it there after a 30 minute drive. No wet spots on the ground. And I've done my hoses and radiator. When the engine is cold is it safe to pop the top open on the Mac tank to check inside? I don't want to introduce air to it and am curious to see if the reservoir is full. But the catch tank is empty. As it is now. Tiny bit of coolant in it. Barely any. I don't know what would cause this since I'm not overhearing at all and am possibly looking into a head gasket even though my oil isn't milky. It's blackish color but I'm creeping up on 2800 miles out of 3000. So it's nearing an oil change. Thanks guys!

[rokinn]

I believe you can open the Mac's tank without worry.  In this configuration it's like taking the cap off of the radiator in an open system, which yours is effectively now.  Try adding some coolant to the overflow tank similar to most cars that have a full indicator on the overflow tank when cold.

[Classy Comanche]

Well that's the thing. I've been doing that. Been battling this since I had it installed. It's cooling great as I mentioned but it just gets lower and lower each time I drive it and let it cool. Now I haven't even opened the reservoir itself since. I did twice actually a while back. But since I never looked inside it. The photo here is a great replacement as to where it is in the plastic tank. It's actually lower than that. I'm just sort of at a loss because I'm not leaking it onto the floor. I don't have milky oil. It's a blackish color albeit. My exhaust is transparent. Isn't black or white. And the heater in my truck blows hot when I have the heat turned on. AC blows very cold when turned to cold. Somthing somewhere is causing it to disappear? Freeze plugs? Thermostat? I'm finding myself adding coolant I think....every 2 weeks? Somthing like that?

[Ωhm]

25 minutes ago, Classy Comanche said:

Somthing somewhere is causing it to disappear?

 

Check your floorboard under the HVAC unit for dampness under the carpeting.

[89 MJ]

 

If it’s dry, I’d do a compression test. 

[Classy Comanche]

Oh I didn't think of that. Is that on the passenger side? I also don't know how you would do a compression test? Does that require you to remove the block head? And also do I need to drive it with heat or air on to see if so? Never thought of this before. 

[AZJeff]

Compression tests are done with the engine intact.  All you need is tools to remove the spark plugs, and a compression tester.  

 

The compression tester can be "rented" from places like Autozone, where if you return the tool after you use it, you get a refund.   

 

Here is a good video from a respected guy on YouTube on how to do a compression test:

How To Do a Compression Test

[Classy Comanche]

Oh interesting. That's cool! OK I'll definitely look into that. I've just been battling this for a bit. It's not been as dire as like doing my starter and stuff. But it's to the point to where its like "ok I'm tired of adding coolant this often. Somthing is up" so I'll definitely do that. Now as to check the floorboard....do I need to run the heat or AC while driving? Or anything? And I assume the HVAC is on the the passenger side below the glove box?

[Minuit]

1 hour ago, Classy Comanche said:

And I assume the HVAC is on the the passenger side below the glove box?

Correct. Coolant will pool on the passenger side if the heater core is leaking. Also look for a sweet smell on the inside.

[Classy Comanche]

Alrighty I'll crank the heat up to max when I get on the road in a few minutes. I've never noticed like any sweet smell. Then again I wasn't looking. So I'll give yall an update on that. Something to note also. I have floor mats so it would, if I'm thinking on this right drip down onto said mat. Which is dry. But I'll definitely check it and my reservoir level too and give an update as well

[AZJeff]

1 hour ago, Classy Comanche said:

Alrighty I'll crank the heat up to max when I get on the road in a few minutes. I've never noticed like any sweet smell. Then again I wasn't looking. So I'll give yall an update on that. Something to note also. I have floor mats so it would, if I'm thinking on this right drip down onto said mat. Which is dry. But I'll definitely check it and my reservoir level too and give an update as well

The coolant has a nasty habit of sneakily running down the inside of the firewall, and then soaking into the jute matting that is under the carpet as a sound deadener/insulation.   You don't normally see it on an floor mats because of this.

 

When heater cores leak enough to keep refilling the cooling system, they are to the point where the heater box has enough coolant dispersed in it that the smell is hard to miss, because all the air passing through the box is passing over a coolant film.  (Unless you actually have just pure water in your cooling system, in which case it evaporates and leaves no trace inside the heater box)

 

If you are seeing a steady loss of engine coolant and regularly needing to top the system off, it's probably something more significant than a leaky heater core.   This is expecially true because you stated you have checked for the usual leaks like hoses and radiator and find no puddles under the engine.   

 

One last thing you can do besides the compression test is to climb under the Jeep and look up at the weep hole in the bottom of the water pump.  It should be dry, and have no evidence of a track of dried coolant that has run out the hole in times past.   If you do it with a hot engine, while it's running, that is a further method for checking for a leak there.

[gogmorgo]

While you’re renting the compression tester, see if you can get a cooling system pressure tester as well. It’s a little hand pump that fits onto the rad cap and squeezes air into the system to pressurize it. It’ll have a gauge on it, run it up to the pressure on the cap and let it sit for a bit. The system should hold pressure, but if it doesn’t, the leak should become obvious. 
 

It’s also worth adding that after filling the system, it’s normal for coolant levels to drop somewhat as air gets pushed out into the overflow and is replaced with coolant. That said you definitely shouldn’t be losing gallons of the stuff. 

[Classy Comanche]

Well I actually just now found a leak that's on my lower rad hose..yay. However the tank is completely full of coolant. Note this hose was installed middle of this year when I had my radiator redone. I also found some coolant on the top of some black cylinder at the back of the firewall right inder the bottle holder on the left side of the engine bay. I can't lie. I don't know how much more repair stuff I can handle. Been steady having stuff done to it. I'm just going to drop it by the shop and have tests run on it, oil changed, hoses checked and reservoir examined. After I saw the leak on the hose it really upset me. Especially after I thought I was ahead on the cooling issue stuff

[Classy Comanche]

And here's a side view as well.

[gogmorgo]

Yeah that’ll do it. 
 

I often find myself with small leaks after opening up the cooling system because I don’t like torquing the crap out of clamps. I’ll always pressure test before sending a vehicle out, but often don’t on my personal vehicles and end up dribbling coolant for a bit before I notice and get around to doing something about it. So you’re not the only one. 

You might get away with just snugging up the hose clamp. It’s also possible something got stuck under the hose or else there’s some corrosion on the nipple.

 

If by left side of the engine bay you mean your left while you’re standing in front of the truck, I.e the passenger side, my guess would be that leak is from one of the heater hoses. Generally though left/right on a vehicle is as if you’re sitting in the driver’s seat, so left would be near the brake booster. Cooling collecting up there would be bad. 
 

 

Older vehicles, especially ones that sat for some time, will do this to you. Once you’ve caught up on all the deferred maintenance it will get better.  But unfortunately a lot of these little issues will only become apparent as you drive it. Learning and addressing some of these things on your own will help to build confidence in both yourself and the vehicle, and will make them seem not so daunting when they occur. Or as hard on your wallet. Honestly, diagnosing the issue is the hardest part of the task of repair the vehicle, and if you’re already doing that on your own, it will usually cost you less to purchase the tools to complete the repair on your own than it will to pay someone else to do it, and a LOT of the repairs are perfectly feasible just with basic and inexpensive hand tools. 

[Classy Comanche]

Very true. When I say left I'm talking standing I'm front of it. It's wet below the coolant reservoir where a larger black cylinder is located. This just really got me discouraged. I'm in my early early 20's and I absolutely adore this truck. But me getting so discouraged almost made me slam my fist down and say "sell it". Although I can't just do that. The thing that sucks is that it's been family owned since. And I'm the 2nd owner. So it would devastate my grandfather if I sold it to someone who just in the end trash it. I'll keep powering through. I'll keep doing fixes. Just going to stop using it as a daily. And that's the bad part. I got another car that's just been sitting all because I got tied up in this and am filled with joy driving it. So I'm just going to have to drive it once or twice I week a reckon after I have it fixed

[cruiser54]

Typical water pump leak.

 

Replace it. Pressurize the system at the Mac's tank and check for additional leaks. 

 

I surely wouldn't be going down the "compression test" rabbit hole at this time. 

[Classy Comanche]

So here's a new sound.....I actually heard it yesterday morning and really didn't think much of it. This what a failing pump sounds like? The sound does eventually stop. But noticeable when cranked up 

[AZJeff]

"Most" water pumps don't make any unusual noise before they fail.  (The one in my MJ was the exception, in that it made an irregular screeching sound because some of the balls in the ball bearings in the shaft were disintegrating.)

 

The most SURE way to diagnose a bad water pump is to look for weeping out of the hole on the bottom side of the "nose' of the water pump housing, where it sticks out to support the pump shaft at the pulley end.

 

Crawl under there with a flashlight when it's running and do a visual exam.

[cruiser54]

Isn't that what we saw in the photo? The leak?

 

Get a water pump. Once the belt is off to do the replacement, spin $#!& that the belt turns. 

[gogmorgo]

Still looks to me like the hose is what's leaking, probably due to a loose clamp. But we can't see above the hose to say for sure. The coolant's coming out somewhere, usually towards the highest part of where it's wet. If that's around where the water pump pulley is, then it's a good indicator the water pump is bad. But if you just go out and change the water pump without actually knowing it's bad, then you might inadvertently fix the problem of a loose hose clamp, you just spent more money and effort to do it.

 

It's also almost impossible to diagnose noises from across the internet. We can't move our head around and hear the sound getting louder, can't use stethoscopes, etc. That sound does sound like a bad roller bearing, but it could be any of the bearings in the belt drive system. It could also be the fan rubbing something. Or the belt catching on something. If you do end up pulling the belt off while you're changing a water pump, definitely give all the pulleys a spin.

[cruiser54]

Here's the water pump leak on one of mine years ago. 

You can hope it's the clamp. Yes, it's sometimes hard to diagnose over the interwebs. 

How about a cooling system pressure check and a stethoscope for the noise?

Are the 2 problems related? Maybe. Maybe not. 

Could be a loose hose clamp. Water pump leaking. Water pump leaking and noisy. Water pump leaking and harmonic balancer making the noise. Alternator bearings going out and a coolant leak. Idler bearing going out with a coolant leak. 

 

 

 

 

[watchamakalit]

Another vote for water pump. If you haven't messed with that lower radiator hose clamp before discovering the leak, its rare a hose clamp spontaneously fails. I just went down this path about a year ago. I can't play the video to hear the sound but given the signs ive seen i would change the water pump.

[Classy Comanche]

It's making a squealing sound. And it's high pitched. I don't think it's my belt because it was 65 degrees. I'm checking some things out. Can't see the weep hole on under the truck due to a plate also. And that's exactly what my leak looks like! Oh my. Yeah that looks identical because it's coming from the coupling up top from the neck and running down, dripping. Yeah I never thought of it being the pump

[Andy in Pa]

That is definitely your water pump leaking.  I had exactly the same thing happen to me, AFTER I replaced the lower hose, thinking it was the problem.

 

So at the risk of confusing this issue slightly, I have a question on what type of cooling system you are actually running.  It says you have an "Open" cooling system, but your still running that metal catch can (replacing the plastic one needed for a "Closed" cooling system).  Does your radiator have a cap, or is it still the older style with no cap?  When converted to an "Open" cooling system, that plastic bottle is removed (in your case it would be the metal catch can) and the cooling lines are re-run as well to eliminate the extra piping not needed any longer.  

 

Then a small plastic overflow bottle needs to be installed so the over-pressure line has somewhere to go in case there is an over-pressure condition and it burps out past the cap on the radiator.  This bottle should have the fitting on the bottom so the fluid can be drawn back into the radiator as it cools down.

 

Seems like you have some redundancy that could be removed to simplify your cooling system a good bit.