bluejeep2001

You forgot that your not running antifreeze...but water and some sort of cleaner...boils a lot closer to 212 than green coolant, even when dirty

algebraic429

I bypassed the heater core and didn’t tighten one of the house clamps so the coolant was leaking from the valve

Very Red XJ

OUCH - there is a freeze plug at the back of the engine close to the firewall that could be leaking or a head gasket. I assume you already looked at the heater hoses and that assembly.

algebraic429

I think im leaning toward the head gasket, when i was burping it before there was a very steady stream of small bubbles coming through the neck of the funnel used for burping. and then after driving it to work i let it idle in the parking lot, in the reservoir there is a steady stream of the same bubble every 1-2 seconds. I guess i can try an emissions tester. not sure about doing the headgasket job myself. Ive done lower intake manifold gaskets on a 5.7 vortec which was very involved so maybe i could handle this.

but i should point out like someone else did i am still running only distilled water and thermocure so maybe the water is just boiling.

RockyMtn96XJ

Head gasket is easy. I did one in about 16 hours of work over a few days last Thanksgiving time off work. The head bolts in the back of the head can be a pain to get to since they are under the cowl. You'll have to tape one of the bolts while its pulled up so you can slide the head out, if I remember correctly. It was a pain for me to torque because I have a digital torque adapter and it was too tall. If you have a regular torque wrench it probably fits under the cowl. I have IN/LBS AND FT/LBS torque wrenches, but the in/lbs wrench doesnt go high enough, and the ft/lbs wrench starts too high for the head bolts.

A thick radiator can also work against you at low speed. If you use a thicker one it cant be full of the tubes that the coolant flows through, which is what will block air flow to the rows in the back of the radiator. So you'd really only be getting good air flow to the first 2 rows of the radiator, then essentially heating up the rows in the back. I'm not sure how to choose the proper radiator when getting a thick one, but the airflow through the fins and coolant tubes is the issue at hand. That's just what I've read. But changing back to the OEM radiator was a good idea I think. I've read that the OEM coolant system is very good when it is taken care of.
If you want to get super OCD about cleaning out the system, you can get much more distilled water than you need to run through after the flush to make sure you get out all of the garden hose water and flush chemicals. If you plan on just running water without anti-freeze there in southern Cal., water wetter will help with the water surface tension and allows better cooling. But it does no good if you mix it with antifreeze.

RockyMtn96XJ

Can read here too.

https://bobistheoilguy.com/forums/th...e-help.385505/

Seems to work for some, not for others. Probably depends on the condition of your coolant system and if its filthy or not.

Great all around website.