Coolant problem

[Liberto]

So I recently noticed that after I drive my truck and it sits the upper radiator hose is flat like... Collapsed... I did what the forum said, run the truck with heater on full blast and cap off, fill as needed then place cap back on and turn truck off..... It's still doing it... It's getting on my nerve... Anyone have ideas?

 

[Rearanger]

Replace the hose maybe?

 

[jasongind]

Keep doing that same process. They system can hold a lot of air, more then you think. Was a hose or the radiator recently replaced?

 

[Liberto]

Yes I replaced the motor so all that came out, the hose seems fine it's not gummy like it's about to go bad or anything. It's not overheating, (per the gauge on my cluster) it's not running funny, it's just collapsing the hose. Someone said to ride the front of the truck on a curb so the fronts higher n then bleed it

 

[Rearanger]

As you know when the system heats the coolant expands into the overflow the amount needed to balance system pressure to that of the rad cap spring
(13-14psi). When the system cools and internal pressure falls coolant will re-enter from the overflow, again balancing pressure. I guess it's possible that for some reason return flow from the overflow is blocked when the engine cools so that falling internal pressure creates a vacuum. If there is air in the system it will just expand and contract with heat so I don't think that's your problem given there's no overheating. The hose should be stiff enough to not collapse. I don't know what type of hose you bought but I'd still look there and also at the rad cap. If there is a vacuum in the system then removing the rad cap after cooling should ballance the pressure and return the hose to full shape immediately.

 

[kimcrwbr1]

+1 on the overflow tube blow it out with air or take the overflow tank off and flush it out it might be crud in the bottom of the tank that dont allow coolant to flow back into the radiator as the engine cools did you put on a new radiator fill cap. if your not leaking coolant you shoud be able to see the fluid in the overflow tank look at the level cold then after it gets to temp.

 

[kimcrwbr1]

With the upper hose collapsed pull the overflow tube off the radiator and see if it dont pull air in it is the cap. if it pulls air in it is the tube or tank flush the tank and if necessary replace the tubing

 

[Liberto]

As you know when the system heats the coolant expands into the overflow the amount needed to balance system pressure to that of the rad cap spring
(13-14psi). When the system cools and internal pressure falls coolant will re-enter from the overflow, again balancing pressure. I guess it's possible that for some reason return flow from the overflow is blocked when the engine cools so that falling internal pressure creates a vacuum. If there is air in the system it will just expand and contract with heat so I don't think that's your problem given there's no overheating. The hose should be stiff enough to not collapse. I don't know what type of hose you bought but I'd still look there and also at the rad cap. If there is a vacuum in the system then removing the rad cap after cooling should ballance the pressure and return the hose to full shape immediately.

yeah when the truck is off and i take the rad cap off it goes right back to normal and the upper rad hose feels stiff like its brand new so..... i guess check my overflow your saying?

 

[kimcrwbr1]

that would be the cheapest as in nothing to blow the tube clear and flush the tank if that dont work replace the cap. mine always had air in the radiator and i discovered the tube was leaking on the overflow tank pulling air as it cooled when I would add water cold it would fill the tank more and just suck air as it cooled

 

[Liberto]

The tank has a handful of sand in the bottom, I cleaned it all out and filled my res tank up with water... I checked it today n the water is still there clear as day and the hose is still collapsing so I'm gonna get a new rad cap n see if that solves my problem

 

[kimcrwbr1]

You did not mention if you can blow easily through the hose from the radiator to the reservor but a new cap never hurts either.