I did a complete flush this morning at my friends auto shop. We got all the old fluid out and flushed with hot water. We hooked up the radiator to this machine that sucked out all moisture from the engine. It was totally drained but we got 4 gallons in. I thought our coolant system took at least 5 what gives. do I just need to give it time. Check later tonight maybe?

 

To get all the water out of the engine you have to put the rear of the truck higher than the front so that the engine is at least level or higher in the rear. Then disconnect the lower radiator hose from the engine to drain the block. You will get between 4 1/2 to 5 gallons of coolent in it.

 

I did mine a couple of months ago and she took 4 gallons. Then I drove 180 miles and the next morning noticed the overflow jug was empty. She took another gallon and has been OK since. The system holds six gallons but I've never gotten that much out or been able to put that much back in. Don't know where that last gallon hides. On the two trucks I've changed it on, both had to be topped off after a good drive and cool down. A good bit of air gets in the system and has to be "burped" out after the thermostat opens.