When I did my intake I drained the radiator. when I filled it back up I let it run a little while and poured in some more I still had some left over so I put it in the overflow thinking there might be air some where so I the drove it for four days I can't see any fluid in the radiator but it isn't sucking the extra out of the overflow tank. Other than that every thing is good. May be petty but it is one of those things that make you go HMMMMMMM.

 

if the rad/coolant system doesnt need anymore fluid then it wont suck any in.. or if you have air bubbles.. does your truck cooling system work alright? meaning does it stay cool and does your heater work? do you hear a sloshing or gurgling noise from under the dash when you turn the heater on? have you checked the level in the rad since you did this 4 days ago?

 

it will not pull fluid from the overflow tank unless the radiator put it there.

meaning, if the fluid in the radiator boils, it expands and the excess fills the overflow tank. then, when you shut the vehicle off, the coolant cools down and contracts, creating a vacuum, pulling the fluid from the bottle into the radiator. since there's no vacuum in the system now, it will not pull from the tank.

fill up the radiator now, if it is low you might have purged some air that was trapped when you changed the coolant. check it every few days to make sure the level stays constant and you are not losing coolant somewhere.

 

i here this when i first drive off on a cold start

 

like i said might have some air bubbles in the coolant.. since the heat exchanger for your heater is under the dash.. u might want to try and bleed it ... best way to do it.. is turn the heater on full blast. start the truck and pul it up on some ramps so its nose high.. let it warm up so the stat opens (when you grab the upper rad hose...it will be hot and you can feel water flowing through it..thats when the stat opens) and then pull the rad cap off and see if theres water flowing past it.. top off little at a time.. keep toping off till the level on the filler neck doent trickle down... leave it runing for another minute or so..shut it off and let it cool down.. (almost completly) and then check it.. if it needs more.. then do the above again.. sooner or later youll get the air out..

 

Also you may want to tighten the radiator cap just to the first click and take your truck for a drive, this won't allow the cooling system to build any pressure and it will force air out of the system. That is if Shotts method doesn't help, but it is sound advice as well.

 

Thanks guys. yea everything works good and I checked the garage floor anf engine no leaks I had already run the heater when I first filled it. Must have been air somewhere. And I forgot the siphon effect till I thought about it a bit.