Radiator Drain & Fill

[KC!]

I'm back on the forum! It's been a while!

Got something I want to run by all of y'all.

I am doing a radiator drain & fill, not out of choice. My drain plug was leaking, then it snapped. I was able to extract the shaft with two Husky picks (feeling like a lucky SOB rn) but in the process of trying to put my new drain plug. I realized I didn't have a gasket so ended up draining the coolant out of the radiator. My full system coolant did just get replaced about a year and a 1/2 ago during an evap coil replacement.

Therefore, not looking to do a full flush, just replacing the 50/50 long life blue coolant that was just drained from the radiator. This is the process I'm planning on follow.
1. Fill up radiator to max & overflow reservoir to max with long life blue coolant (50/50 mix)
2. Drive it around w/ heater on (not sure if this matters) for a few miles each day ensuring to hit operating temp.
3. Each time checking overflow level & filling up to max. I do have a steep driveway so can park on incline if that helps.
4. Stop repeating cycle until overflow reservoir stabilizes at max.
Does this sound about right?

 

[TerryD]

Once you get it up a bit, with the caps on and engine cold.

1. Pinch the overflow hose from the radiator to the degassing bottle closed.
2. Squeeze the top radiator hose and hold.
3. Release the overflow hose and pinch off the small hose coming off the heater tee fitting that runs under the IPDM to the degassing bottle.
4. Release the top radiator hose.
5. Repeat till the hose from the heater tee to the degassing bottle is full and refill the degassing bottle to the proper level.

 

[KC!]

Once you get it up a bit, with the caps on and engine cold.

1. Pinch the overflow hose from the radiator to the degassing bottle closed.
2. Squeeze the top radiator hose and hold.
3. Release the overflow hose and pinch off the small hose coming off the heater tee fitting that runs under the IPDM to the degassing bottle.
4. Release the top radiator hose.
5. Repeat till the hose from the heater tee to the degassing bottle is full and refill the degassing bottle to the proper level.

I’ve never seen this & this is all done while the engine is cold?

 

[TerryD]

I’ve never seen this & this is all done while the engine is cold?

Yes. It's how you bleed that little hose and prevent an air bubble from air locking the system. This hose is the primary reason Nissan recommended using a vacuum bleeder on the system.

It also keeps you from air locking the degassing bottle. If you notice the divide and TINY slot that allows coolant from one side to the other, this is an issue if you over fill the bottle before the entire system is bled properly. It will completely fill the back half and because of pressure from the radiator, you'll have a huge air bubble in the front that can't bypass back to the rear half to be vented properly.

 

[KC!]

Yes. It's how you bleed that little hose and prevent an air bubble from air locking the system. This hose is the primary reason Nissan recommended using a vacuum bleeder on the system.

It also keeps you from air locking the degassing bottle. If you notice the divide and TINY slot that allows coolant from one side to the other, this is an issue if you over fill the bottle before the entire system is bled properly. It will completely fill the back half and because of pressure from the radiator, you'll have a huge air bubble in the front that can't bypass back to the rear half to be vented properly.

Understood. Thank you! When you say pinch off is this all with hands or pliers/vice grips

 

[TerryD]

I just use my fingers. They are relatively soft hoses.