How to fill coolant after replacing radiator

[saffy]

Replaced the rad in my 2000 TJ 4.0 liter. I'm wondering how I should go about filling the system back up with coolant. I had the coolant changed 2 years ago by a shop and it's green but unfortunately I have no clue what it is and i'm nervous to just mix any old coolant with what's in the system already.

Would there be any harm in simply filling the radiator with distilled water for now? I don't have time to do a complete coolant change currently. I'd eventually do the change before it gets real cold here.

If this is fine to just fill w distilled water, what is the procedure for this? how do I bleed the system of air? pretty lost on how to do this.

 

[TheBoogieman]

I fill my radiator with the Jeep running and leave the cap off until it reaches operating temp. Never had to burp the air out of any Jeep.
p.s. I always use the "All makes and models" green antifreeze.

 

[CharlesHS]

IF the thermostat was removed; ensure a 1/16" bleed hole is drilled in the thermostat face and clock this bleed hole at the 12 o'clock position.
When refilling the radiator have the vehicle front slightly higher than the rear and slowly fill the radiator to allow the air to burp out will the engine is running.

 

[saffy]

I fill my radiator with the Jeep running and leave the cap off until it reaches operating temp. Never had to burp the air out of any Jeep.
p.s. I always use the "All makes and models" green antifreeze.

thanks for the advice of how to fill it. but unfortunately I'm a bit scared to mix what I have in the system currently with any old coolant because of the 'turning to sludge' concern.

 

[saffy]

IF the thermostat was removed; ensure a 1/16" bleed hole is drilled in the thermostat face and clock this bleed hole at the 12 o'clock position.
When refilling the radiator have the vehicle front slightly higher than the rear and slowly fill the radiator to allow the air to burp out will the engine is running.

stat was not removed. and sounds good. any idea if filling with distilled water for now until I have time to completely replace all the coolant is ok?

 

[CharlesHS]

stat was not removed. and sounds good. any idea if filling with distilled water for now until I have time to completely replace all the coolant is ok?

Depends upon the amount of remaining coolant in the engine; you do want some of the coolant properties remaining.
The filling with distilled water should be fine....
Make sure you replace all the coolant prior to the colder months of Colorado.

 

[01CuHed]

Filling with distilled water would be OK. What CharlesHS said!

 

[RMETeeJay]

Replaced the rad in my 2000 TJ 4.0 liter. I'm wondering how I should go about filling the system back up with coolant. I had the coolant changed 2 years ago by a shop and it's green but unfortunately I have no clue what it is and i'm nervous to just mix any old coolant with what's in the system already.

Would there be any harm in simply filling the radiator with distilled water for now? I don't have time to do a complete coolant change currently. I'd eventually do the change before it gets real cold here.

If this is fine to just fill w distilled water, what is the procedure for this? how do I bleed the system of air? pretty lost on how to do this.

Download the FSM for your model year from here and follow the refill steps. As others have said, it's safe to use only distilled water this time of year. There will be less corrosion protection, so don't leave the water-heavy mixture in there for any longer than necessary.

When you do the full drain/refill, don't skip pulling the block's drain plug (easy with some extensions and an 8mm square) in order to get most of the old mixture out. After refilling, keep checking the reservoir level for a week or two to top up the reservoir as the trapped air escapes.

 

[TheBoogieman]

thanks for the advice of how to fill it. but unfortunately I'm a bit scared to mix what I have in the system currently with any old coolant because of the 'turning to sludge' concern.

People overexaggerate that stuff with no first-hand knowledge of the consequences. I've done it on many Jeeps with no ill effects. I just don't post it here. I use a chemical flush every 2-3 years though regardless of mileage. If you're skeered, don't do it.

 

[TheBoogieman]

Depends upon the amount of remaining coolant in the engine; you do want some of the coolant properties remaining.

What will happen if there is?

 

[tworley]

Drain the block, flush the heater core and put in Zerex. Its only a couple more steps from where you are already at.