anytime i start my truck, or let it idle then touch the throttle, i hear bubbling or water rushing into my heater core, and sometimes it does it just drivin down the road. the radiator is completely full. theres no oil in the water or vice versa, n no white smoke out the exhaust, n the truck doesnt overheat. so i've basically ruled out any kind of a head gasket issue. im pretty sure it aint normal, plus its kind of annoying. any ideas what might be goin on? thanks guys

 

Does the over flow go down very slowly? I have to same sound and a very small leak at the heater core outlet hose causing it to suck air in when it cools that it has to push back out when it warms up/runs. Does it stop when the truck fully warms up? You might want to take the clamp off the outlet heater core hose start the truck cold and either pull the hose off to amke a crak or use a hose pick to make a small leak while filling the radiator to force all the air out of the heater core.

 

Sounds like you have air in the system. You will need to find out how and why it is there.

 

Mine was Doin the exact same thing just b4 it puked the head gasket...

 

Heater core is probably leaking.

 

You could do a vacuum fill and determine if its leaking, that way you could eliminate the air in the system if that was the cause and flush your coolant at the same time.

 

the carpet isnt gettin wet n the overflow stays where it is.
a month or 2 ago i was gonna get studs n a new head gasket but my friend got in a real tight jam so i loaned him the money i was gonna use for that. but its definitely the next thing im gonna do.

 

my new prodgect truck does the same thing, but i have other things to fix first. I would like to know what you find. I hope its not heater core i heare they are a night mare to change.

 

A buddy of mines truck did this exact thing it sounds like. In this case it was just that the heater core was plugged type of thing. You would have heat sometimes, and sometimes you better wear your coat.

 

you have air in the cooling system. mine did the exact same thing after i did my kdp. when i refilled the radiator i did not leave the cap off while running it. took me awhile to figure it out. but after i let it run for a few minutes with cap off it went away.