Cycling Out Engine Coolant By Running Engine

[PhotoRecon]

In checking out how to change the antifreeze on my 2000 GMC Sierra 1500 with the 5.3L I haven't been able to locate any coolant drain plugs on the engine block.

 

I mentioned this around and a mechanic suggested that after draining all the coolant you could run the engine for 30 seconds to allow the water pump to cycle the coolant trapped in the block into the system where it could then drain. I questioned that with no coolant the water pump might be damanged, even if only for 30 seconds.

 

Any comments on this procedure?

[txab]

You still won't get all the coolant out that way. There are block plugs that can be pulled. But you can just as easily flush with clear water to get all the old coolant out

[rockcrusherrevived]

In checking out how to change the antifreeze on my 2000 GMC Sierra 1500 with the 5.3L I haven't been able to locate any coolant drain plugs on the engine block.

 

I mentioned this around and a mechanic suggested that after draining all the coolant you could run the engine for 30 seconds to allow the water pump to cycle the coolant trapped in the block into the system where it could then drain. I questioned that with no coolant the water pump might be damanged, even if only for 30 seconds.

 

Any comments on this procedure?

 

if i were doing a flush i would remove the thermostat housing and bottom rad hose

[PhotoRecon]

txab:

 

I have to admit I'm confused.

 

If you flush the system with clean water won't that leave straight water where the old coolant was unless the block drain plugs are used?

[txab]

Yes. I always finish it off by dumping 2 or 3 gallons of distilled water. Then it's ready to add back pure coolant. If you're concerned you can always pull the block plugs