Just did intake manifold gasket...still losing coolant. Nooooooooooo!

[Mangonesailor]

I say this because when I drained the rad (from the lower rad hose) only 7-8 litres drained from the truck and that's all I poured back in to top up the rad.

If you do not "unplug" your heater core heater hose from the manifold, or uncouple the return hose you will not drain a significant amount from the block. I've experienced the same thing with multiple cars and trucks... I always remove a heater hose when draining and filling. Also, refill with the nose of the truck up a slight/steep grade.

When I'm at the last stages of refilling I fill the rad. neck to the brim (with coolant in the overflow jug) and place my hand over the neck to form a seal. Next, I squeeze the upper rad hose and force coolant and air from it into the overflow jug. When you release the hose (whilst maintaining your hand over the rad neck) it will suck only coolant back into the rad. You'll hear the air in the rad and hose "swish" around when you squeeze it.... so do this until you hear it stop "swishing." After all of that just drive it a couple of times and you should have all of the air out.