Flush the block without Radiator (85 BJ70 with 3B) (1 Viewer)

[bj70alex]

Hi,

I had to fix the radiator. I took it to the shop to rod it out. Before taking the rad off, I should have flushed the system, but I didn't.
Which ar amy best options to get rid of the old green antifreeze form the block and the heater core? Honestly I don't want to remove the block heater, major PITA.
Any suggestions, ideas would be greatly appreciated.

Thanks,
Alex
85 BJ70
93 FZJ80

 

[fjbj40]

unhook the out line from your heater core in the engine bay and stick your garden hose on there and slowly turn on the hose . This will back flush the whole system .

Daryl

 

[bj70alex]

Daryl,

How can I make sure that after flushing the system, the system will not have some water left from flushing it?

Thanks,
Alex
85 BJ70
93 FZJ80

 

[cruiser_guy]

There will ALWAYS be some water left in the system, same as when you do an oil change there is ALWAYS some oil left in the engine. Look at the fluid quantities in the FSM and you'll see dry fill quantities are different from refill quantities.

 

[Greg_B]

Backflush the system as mentioned, then take out the block drain plug (brass bolt into a fitting on the side of the engine) to drain the remaining water from the block. I want to say the bolt is left rear of the engine, and is 14mm, but don't quote me.

gb

 

[bj70alex]

Question,

Do I have to remove the thermostat or just leave it alone?

Thank you,
Alex
85 BJ70
93 FZJ80

 

[cruiser_guy]

Backflush the system as mentioned, then take out the block drain plug (brass bolt into a fitting on the side of the engine) to drain the remaining water from the block. I want to say the bolt is left rear of the engine, and is 14mm, but don't quote me.

gb

That still won't get all the water out. I had water all over the floor of the garage when I was rebuilding the 3B as soon as I tilted the block on it's side to pull the piston skirt oilers or take the oil cooler off (I took the drain plug out while the engine was still in the truck).

btw The drain is on the left side of the block behind the injection pump and under the EDIC motor.

 

[BJ70/85]

If your thermostat is as old as the Rad.-replace it with a new gasket. When you have it out flush it then. You can watch the coolant come out, when its clean, stop. Replace the Stat., drain the Rad. of water, and fill it with coolant. Let the water pump mix them. This is the Bow-Hunk way, coolant should be 50/50 with distelled water, but who does that?