Where did my coolant go?

CybrSlydr

CybrSlydr

TJ Addict
Supporting Member
Lifetime Supporting Member
Joined
Jan 17, 2018
Messages
1,313
Location
Casper, WY
Was driving to an appointment this morning. I got there a few minutes early so I was sitting in my Jeep with it running.

I hear the beep and see the Check Gauges light is on and the coolant temp is creeping into the red.

I shut the Jeep off, got out, and looked under. No puddle or drips.

I open the hood and see the overflow reservoir is almost empty.

Last time something like this happened, the reservoir cracked and sprayed coolant all over the inside of the hood - but there's no spray or leaks I can hear from the radiator.

I walked to an OReillys and grabbed two bottles of the Zerex G05 coolant and walked back. I poured a bit in and looked/listened for any leaks, didn't see any or hear any.

My concern at this point is that it's a head gasket and it's gotten into the engine/oil. So I filled up the coolant, took about 1/2 a bottle, maybe 2/3s. Drove it home about 2 miles - other than reading around the "1" in the 210 on the coolant gauge, it seemed fine. Checked for leaks when I got home - zero leaks.

So I pulled out the engine oil dipstick to see if it was milky - engine oil looks ok to me (other than being in need of change) - didn't appear milky at all.

51619162975_58b541bba7_h.jpg


So, now I'm planning on getting the radiator flushed soon as I'm sure that if it was low enough to start overheating that there's air in the system now.

What else should I be looking for? I mean, no leaks, no sprays, nothing - it's like it vanished into thin air. Last time it'd been filled was when the new radiator was put in, about 18mos ago.
 
I slowly lost coolant thru the drivers side rear freeze plug on the block. Would go right under and not even hit the exhaust. Never saw it leave the jeep until I saw the mysterious puddle that never dries.
 
  • Like
Reactions: CybrSlydr
1Salty Dawg said:
I slowly lost coolant thru the drivers side rear freeze plug on the block. Would go right under and not even hit the exhaust. Never saw it leave the jeep until I saw the mysterious puddle that never dries.
Click to expand...
That's a bit of a bummer... Freeze plugs are a lot more expensive than a coolant flush.

But... If that's what I gotta do, then I gotta do it.
 
If that is your case make sure to get the Mellen brass plugs, I had a shop do it, cost $200 but I supplied the parts. Easy to get to when its on a lift and not just on jackstands in the garage. Also do a coolant pressure check.
 
pagrey said:
Bad radiator cap can cause you to loose coolant, they are cheap. Often it's the little spring in the center of the cap that breaks and prevents it from sealing.
Click to expand...
Radiator cap is the same age as the radiator. Can't imagine it's bad already - it's less than two years old.
 
pagrey said:
Bad radiator cap can cause you to loose coolant, they are cheap. Often it's the little spring in the center of the cap that breaks and prevents it from sealing.
Click to expand...
Wouldn’t that fill the overflow? OP indicated it was almost empty. I guess it could have sucked it back in during a cooling cycle, though.
 
  • Like
Reactions: CybrSlydr
NashvilleTJ said:
Wouldn’t that fill the overflow? OP indicated it was almost empty. I guess it could have sucked it back in during a cooling cycle, though.
Click to expand...
When the little spring is broken the coolant boils, all the way through the overflow and out the vent, it's a slow leak that drains the system. The broken spring also prevents the system from pulling coolant back into the radiator so it just continually steams out.
 
  • Like
Reactions: txbemis69, KP_Jeep_TJ, NashvilleTJ and 1 other person
pagrey said:
When the little spring is broken the coolant boils, all the way through the overflow and out the vent, it's a slow leak that drains the system. The broken spring also prevents the system from pulling coolant back into the radiator so it just continually steams out.
Click to expand...
Good point. I hadn’t thought about the coolant being in steam form.
 
Just went out to check the radiator cap and noticed a small puddle under the Jeep. Got some pics I'm uploading to Flickr for you folks right now.
 
Cap looks okay, I'm sure that center part springs back like it's supposed to. Now you just gotta track down that leak. The marks on the frame are really close to where the heater core drain on the firewall is. Hopefully it ain't that.
 
pagrey said:
Cap looks okay, I'm sure that center part springs back like it's supposed to. Now you just gotta track down that leak. The marks on the frame are really close to where the heater core drain on the firewall is. Hopefully it ain't that.
Click to expand...
Might see if the place I take it to flush the coolant system can spot a leak.

Yeah, I've read getting the heater core replaced is an absolute chore - and not cheap either.
 
CybrSlydr said:
Might see if the place I take it to flush the coolant system can spot a leak.

Yeah, I've read getting the heater core replaced is an absolute chore - and not cheap either.
Click to expand...
Bases on that leak location on the passengers side, I’d follow @pagrey ’s advise and check all around there. If you have what looks/feels/smells like collar coming from the HVAC box drain tube, yiu most likely have a leaking heater core. Check where you heater hoses attach to the core on the firewall. You might get lucky and and just have a loose connection or a split hose.

Do you smell that sweet coolant smell when you first turn the heater or defrost on?

As far a cost, I did my own a few years back. I took it to a shop to get the A/C refrigerant evacuated before hand. I asked the guy how much they would charge if they were to do the whole job. He said $800-850 range.
 
MountaineerTom said:
Bases on that leak location on the passengers side, I’d follow @pagrey ’s advise and check all around there. If you have what looks/feels/smells like collar coming from the HVAC box drain tube, yiu most likely have a leaking heater core. Check where you heater hoses attach to the core on the firewall. You might get lucky and and just have a loose connection or a split hose.

Do you smell that sweet coolant smell when you first turn the heater or defrost on?

As far a cost, I did my own a few years back. I took it to a shop to get the A/C refrigerant evacuated before hand. I asked the guy how much they would charge if they were to do the whole job. He said $800-850 range.
Click to expand...
I've had that smell almost the whole time I've had the Jeep. That's... 4 years in March I think?
 
  • Like
Reactions: MountaineerTom
If it is you’re core, you can make a
bypass hose for you’re heater hoses to buy you a little more time.

Seeing that you’re in Wyoming though, you might not want that extra time.
 
  • Haha
  • Like
Reactions: Modoc Guy and CybrSlydr
Top Bottom
Back