TheGreatGazoo

can someone tell me the proper way of Burping the sealed pressurized Coolant system for my 89 Xj . I searched but every one says something else. Before anyone says to convert it over to the new style radiator, all im doing is replacing my hoses i never had any over heating issues before even with the A/C on in 95* weather so i'm leaving it alone till time comes to replace the rad when it goes bad. I'm just doing some pre winter maintaince

Big_Bear_Walt

Jack up the rear of your XJ so the back of the engine is raised.
With the engine off, fill the system until the coolant bottle is topped off, leave the cap off.
Using a 13mm deep socket, unscrew the coolant temp sensor (located on the top of the cylinder head at the rear on the driver's side), and slowly start to pull it out until you hear air escaping (you don't have to pull it all the way out, it extends down beyond the threads), coolant will soon follow, at which point you screw the sensor back in and tighten it snugly.
Now top off the coolant bottle if necessary, and install the cap.
When the engine reaches operating temperature, the excess coolant will be forced out through the pressure cap as the system stabilizes itself. This is a normal process so don't be alarmed by the escaping coolant.
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and use the XJ for it's intended purpose!!!

cruiser54

And when you're done with that, replace your bottle cap with a 703-1396 cap from Napa. It holds more pressure, has threads that hold tighter even on an old bottle, and has a lower profile to keep it from rubbing on the hood. Best of all, it's not a chinese piece of crap like all the black caps out there.

djb383

Since coolant flow exits the front of the motor and air naturally rises in a liquid (front of the motor is higher and that's where air migrates/escapes), I never have understood why raising the rear of the vehicle would help burping.

cruiser54

I've never burped a Renix since 1987 when they came out. Just filled the bottle to the top, put the cap on and run it.

djb383

Kinda what I was thinking.....but tha strange "jacking up the rear" method keeps coming up.

tr6guy

jacking up rear of jeep makes rear of cyl head hi point on engine. Air rises so easy to bleed air from temp sender...

Cherokee89

Drill a small hole in your thermostat, about 3mm and you will be ok. Have done this on a few renix XJ now and it works like a charm.
And replace the cap with a better one, and remove the water flow control valve, it restrict water flow flow to the heater and will sooner or later break, and when you do that flush the heater core and you will get good heat for the winter.

cruiser54

Good advice here.
Except, save yourself the trouble and get a Mopar stat #83501426. Has a hole and a little "jiggle valve" in it. Bleeds well, and temp comes up quickly in the winter.

703-1396 is the # for the cap at Napa.

Ditching the water control valve has other benefits besides increasing flow. If it's not there, it can't explode in to pieces at some inopportune time.
And, coolant constantly flows through the heater core reducing the possibility of build-up of crud in it.

djb383

If the front of the motor is already the hi point and coolant (and air) EXIT at the front of the motor what's the point of changing one hi point to another? That hole in the front of the head is a huge air bleed compared to the small hole in the rear.