[Vic Denim]

My jeep hasn't been getting up to temp so I changed the thermostat. I used a new gasket with some rtv. I followed the instructions and tightened the thermostat housing down finger tight, waited an hour and torque it down. I'm gonna let it cure till tomorrow and then burp the system.

So, I've never "burped" any coolant system. I've been reading and reading and I'm seeing about a dozen different ways of doing this.

What's the simplest way to insure I get the air outta my system. Do I turn the heat on? Cap on or off? Help me out here, y'all.

TIA

 

[hanlondave95]

On a 5.2, I fill it with the engine off, put the cap on and run it till the thermostat opens or it starts getting hot. Let it cool till the pressure is off and top it off, engine off again and recheck after it cools off once more.
There’s really nothing to burp.

 

[jeepjeepster]

Ive read about a lot of people having issues burping the 4.0, but Ive never had an issue. I fill it up, start and let it run, top it off as needed.

 

[Mile High]

Never had any issues bleeding the cooling system on my old 4.0 or on my 5.2. Like every one has said, run it and it will bleed air out on its own. If you are really having trouble park on an incline with the engine up high.

 

[speedbrake]

fill it with the engine off, put the cap on and run it till the thermostat opens or it starts getting hot. Let it cool till the pressure is off and top it off, engine off again and recheck after it cools off once more.

This. 👍🏻
As hanlondave95 says, the important part is the ‘get it hot (operating temperature), let it cool, top it off‘ cycle, repeated a couple times. Just as important, keep the coolant overflow tank filled too. Because as the engine cools, a vacuum is created which sucks coolant from the overflow tank back into the radiator. That overflow tank coolant is displacing the air in the system with each cycle. It’s an iterative process and the first cycle will suck A LOT of coolant from the overflow tank, second time less, third time even less.

 

[Vic Denim]

Ok, thanks y'all. I've been giving the rtv 24 hrs to cure and was reading posts with different "proper" ways of finishing this thermo replacement process.

 

[RedRiverT]

The heater core is where people have trouble getting the air completely out. You don't have hot heat because it has air trapped and I guess the bubble occupies part of the volume of the inlet and/or outlet tube and thus the amount of coolant that can flow through is restricted.

 

[speedbrake]

You don't have hot heat because it has air trapped....bubble occupies part of the volume of the inlet and/or outlet tube and thus the amount of coolant that can flow through is restricted.

In that case, it's not that the heater core air bubble restricts coolant flow. It's that air has terrible heat transfer qualities. Water (coolant) is much better at transferring heat. That's why 'air in the core, cabin heat not as strong'. OP said "My jeep hasn't been getting up to temp so I changed the thermostat. " I took that to mean not reaching operating temp, not didn't have heat.

Regardless, what Mile High said can get that heater core air out of the system. Doing heat, cool, topoff cycle on an incline.

If you are really having trouble park on an incline with the engine up high.

 

[Vic Denim]

In that case, it's not that the heater core air bubble restricts coolant flow. It's that air has terrible heat transfer qualities. Water (coolant) is much better at transferring heat. That's why 'air in the core, cabin heat not as strong'. OP said "My jeep hasn't been getting up to temp so I changed the thermostat. " I took that to mean not reaching operating temp, not didn't have heat.

Regardless, what Mile High said can get that heater core air out of the system. Doing heat, cool, topoff cycle on an incline.

Yes sir, you read that correctly @speedbrake . Heat works fine, engine wasn't getting up to proper temp. Finished everything and all is well. Thanks again, everyone.