Heater Core Hose Question

[Runeddyrun87]

Hey all. Still trying to track down why i have coolant bubbling in 06 Tj. Head gaskets new. New T-Stat. Coolant Flush. New degas bottle. New radiator. The coolant just keeps bubbling.

I'm down to its the water pump or the heater core.

Replacing both of those currently.

My question is in the manual it shows that the hose that comes out of the top of thermostat goes to the lower connection on heater core at the fire wall. But my hoses are the other way around the top T-stat hose goes to the top of heater core. I thought for a min that i had just mistakenly attached them backwards. But the hoses are two different sizes so i don't think you can flip them. The hoses are even different lengths so its got me kind of puzzled. Does it matter. Surely it would. Any help be awesome. thanks in advance. ED

 

[JKP]

Heater core makes no difference, you could just bypass it completely.

Did you replace the radiator cap?

 

[Runeddyrun87]

yes sir replaced the cap. i thought about a bypass just to see if that fixed the issue. but just going change it out. Blink about three more times and it with be winter time.

 

[JKP]

If there isn't coolant coming out of the drain or in the passenger floor, it's not going to fix your problem.

 

[JKP]

And the figure is wrong.

 

[pagrey]

The heater hoses only go on one way, they are different sizes. The figure doesn't matter. It sounds like you have a coolant leak, that normally causes the bubbling. Have you done a pressure test? It might help you find the leak.

 

[Runeddyrun87]

Just getting wrapped up. Going let it sit for a day for rtv setup. So when i got the Jeep the head gasket was bad and i have been battling the coolant bubble for awhile. I know the new head gasket is good BC i tested it. From the beginning something i noticed and didn't think about until way later is that everything had a bunch of crystalized junk in it. like i said didn't think to much about it until i realized previous owner pumped the coolant system fuel of sealer that's what i believe all the crystalized stuff is in the system. i looked at a bottle of it at Napa. It goes something like you drain the coolant and fill with water add the sealer and run the motor for 45 min then shut off and cool then repeat then drain the system and let it sit for 24 hours to let the sealer setup. My thought is this has clogged up multiply parts of the system. It would run with out overheating. But the temp gauge be a touch over the middle line. When i put the new radiator on it that fixed that issue it stays right in the middle but coolant still bubbling. I have no doubt that if i drove it any where more then 30 min it would overheat so trying to replace anything that might be clogged up. I'm not sure if that's sound logic or not just seems possible to me. I just don't know where else in the system i could have a leak it. Tomorrow night if the problem is still there i guess i will pressure test it and go from there. The hoses are older but i inspected them when i had them off and they appear to have no holes. I thought maybe a small pinhole or something in hoses maybe ? it doesn't leak coolant onto the ground so ?? I have built a bunch of Tjs and this one just does not seem to want to be road ready. Just keep trying to figure it out. I apologize about the long winded response. I sure do appreciate the quick reply's


JKP (And the figure is wrong.) Whatca mean there ?

 

[freedom_in_4low]

JKP (And the figure is wrong.) Whatca mean there ?

He means the heater hose drawing is wrong. I don't personally know that but there are documented errors in the fsm so this may be one of them.

It makes sense for flow to go in the bottom and out the top because the flow pushes air out instead of back in but I've never had the core out so maybe that's what it does behind the firewall for all I know. At any rate there are plenty of other design choices that make it seem like no one working in automotive cooling and HVAC has ever worked in the HVAC industry.

 

[JKP]

In general, boiling with the temp at 210 is due to a bad cap, pressure leak somewhere in the system.

Assuming you checked head for cracks?

 

[hear]

He means the heater hose drawing is wrong. I don't personally know that but there are documented errors in the fsm so this may be one of them.

It's almost like we should have a sticky thread to identify these discrepancies. Nah, too much work.

 

[Jerry Bransford]

yes sir replaced the cap.

Did the replacement cap have the correct 18 lb. pressure rating?

 

[freedom_in_4low]

It's almost like we should have a sticky thread to identify these discrepancies. Nah, too much work.

make a thread in the Resources section with what you've got..I know you came across some in the transmission. We can add this one. If it pans out I bet Chris will give in and sticky it.

Maybe to keep it from getting too specific (and too small) it can be errata in general factory documentation, not just the FSM. The GL5 recommendation for the AX15 lubricant would be an example from the owners manual.

 

[Runeddyrun87]

Well that seemed to fix the issue. I don't know why. The water pump looked good and did not seem to have any issue. Let it run this am for about 2 hours and then drove it about 30 miles. Temp gauge stayed under the middle and never moved. Shut it off multiply times and the coolant is not bubbling. Was feeling pretty motivated and got hardtop put back together and installed while i was waiting. The real test is going be this afternoon after i charge the AC up. Done that 2 times then had to pull it back apart. Hopefully third times a charm.

I did get the correct cap and inspect the head for cracks and run a straight edge over to check for warping. However after reading comment i started looking into how to check for cracks and did not know about magnafluxing the head because they commonly crack where ya cant see them with naked eye. Anybody know what someone charges to do that the electro magnets are pretty dam expensive

Ya how bizarre the manual is incorrect. I will keep that in mind moving forward. I reckon the lesson is don't 100% trust the figures. That be a great idea to STICKY them as people find them.

 

[Runeddyrun87]

Looking slick