Coolant Loss. Dip stick clean, and no leaks

[AnotherOldJeepGuy]

29 minutes ago, Eagle_SX4 said:

get under the cab and check for any antifreeze on the bottom side of the floor boards.

Since I learned earlier that the dye I put in originally is persistent, if there is any coolant there that got there since July, the blacklight should point that out pretty quickly.  It stands out better at night, so I'll take a look after sundown.

[AnotherOldJeepGuy]

Got under there with the light, I don't think I see anything that convinced me it was coolant.  There were a variety of colors here and there, hard to know what all may have been collected there over the last 36 years .  

[89 MJ]

Have you let it get up to temp and then inspected everything under the hood while it’s running? It might be pushing out somewhere while it’s running and the cooling system is pressurized. 

[AnotherOldJeepGuy]

8 minutes ago, 89 MJ said:

Have you let it get up to temp and then inspected everything under the hood while it’s running? It might be pushing out somewhere while it’s running and the cooling system is pressurized. 

Yeah I have looked both running and not running and anything I have been able to find visually has been fixed.  But I may not be seeing every possible spot.

[AnotherOldJeepGuy]

Coolant dropping fast .  My center mark is basically at the target fill level.  At this rate it looks like I will have to refill to that target level every ~300 miles.  Delivery tracking says my oil sample should get to Blackstone sometime today, should not be too long until I have analysis to show if it's going into the oil or not.

[AZJeff]

27 minutes ago, AnotherOldJeepGuy said:

Coolant dropping fast .  My center mark is basically at the target fill level.  At this rate it looks like I will have to refill to that target level every ~300 miles.  Delivery tracking says my oil sample should get to Blackstone sometime today, should not be too long until I have analysis to show if it's going into the oil or not.

Hold your breath and cross your fingers.  I am pretty sure you will tell us the results, one way or another 

[fiatslug87]

It usually takes Blackstone a week to send results.

[Chico]

Do you know how old the expansion tank up against the firewall is?

 

 

[Chico]

10 minutes ago, Chico said:

Do you know how old the expansion tank up against the firewall is?

 

 

Pressure tank. Sorry. You have a closed system correct? Work with me here because I'm not a mechanic, my MJ still hasn't gotten here, and I haven't looked at one of these since 2008.

 

The tank you have is plastic. There's only 3 places that coolant could leak from there correct? The two hoses and the cap. Tell me if I'm wrong because I don't remember that far back.

 

The "Chico" version is replace the two hoses, all the clamps, AND the pressure tank and plastic cap.

Then refill and burp the system and see if the loss stops. I remember changing mine to an aluminum one on my 88 back in 2008. Can't remember the brand but should be in my "build" post from 20 years ago if you can find it.

 

The correct version would be to check for leaks somehow under pressure at the hoses and cap. Pull the cap, look underneath, see if it's "cruddy".

 

Reasons I bring this up..

Common problem on JLU's today is the "expansion tank". System pressurizes and heats up, the plastic seam that runs horizontally across the middle of the tank let's vapors escape once the liquid hits a boiling point and some of it turns to steam slowly losing coolant.  Once the engine is turned off, the coolant and tank drop in temperature and the tank magically "plastic welds" itself together again with no visible sign of any leaks.

Loss is slow to everyone this has happened to but we've all remedied the problem by switching to an aluminum tank from Mishimoto.

 

Note: I didn't have this problem on my JLU. My coolant loss was a very slow "vapor" leak again but from a rubber hose where the system meets the firewall. Never saw a drip either in this instance. 

 

MJ....

This system is "more pressurized" (excuse the term, not a mechanic.), 20 years ago I had a similar issue even after replacing the whole cooling system. In my case, the truck would also run HOT even after multiple tries at burping it. Now, I'm sure everything else needed changed anyway since at the time the parts were already 20 years old but, in the end ,the loss of coolant and overheating problem was because coolant was evaporating up thru the old, worn, cracked cap threads on the top of the plastic tank and cap. Once I swapped out the plastic tank and cap to aluminum, all those problems were magically solved, even though none of us ever saw any coolant come up thru the cap opening area.

 

Can't be sure this is your issue but just a long story and suggestion.

I'll see if I can find the aluminum tank I used.

Keep us updated.

 

Thnaks!

 

 

 

[Chico]

Here's the  pics of the metal tank and plastic bottle we used 20 years ago. I still can't remember exactly why, what, we did who, so I'll have to brush up on my reading. Also, not my pic, think it was Pike's. I started reading old threads and memories started to come flooding back about how much of a PITA this closed system was to deal with back then and am now banging my head against the wall questioning WHY IN THE WORLD I thought it was a good idea to buy an MJ again 

I'm actually having chest pains from the anxiety about the thought of it. 

 

  

[fiatslug87]

The aluminum tanks were from Mac’s Radiator, I don’t  think they sell them any longer.

[Chico]

I just noticed that while going back in time thru 2008 and making myself even angrier that I didn't "step by step" detail how I did everything in my Build post. The link to Mac's that I had is now inactive. 

So..

Sorry to hijack the thread guys but, where is everyone now getting their tank? Mishimoto?

I'm now starting to break out in hives anticipating the MJ getting dumped on my driveway if it ever shows up.

[Chico]

AnotherOldJeepGuy

Also just read your older post where you said you've replaced your plastic tank 4 times already over the years and had problems with the caps already.

More and more I'm leaning toward you might be "boiling off" coolant thru the tank or cap again without it being visually noticeable.

Does anyone here know if it's possible that your cooling system is under to much pressure?

Is that even a possibility?

 

And I'm going to start researching it now but first thing I'd do anyway is get away from the plastic tank and move to an aluminum one. Even if you're not loosing coolant thru there or the connected hoses.

[AnotherOldJeepGuy]

It is true I have replaced my tank probably 4 times over the years, the most recent was sometime in the last 12-18 months so the one in there now is fairly new.  I can't prove the cap is not allowing any evaporation, but I can say there is no sign of any leak at that tank.  I actually have the next new tank already on the shelf in the garage, they go out for me often enough that I usually have the next new one on hand.  I would love to replace the plastic tank with the aluminum version, but sounds like the replacement noted here is no longer available.