Radiator not pulling from reserve tank

[DMT78]

I've got a problem with my 2000 dodge dakota 3.9L V6. I recently flushed my coolant system and noticed that the system wouldn't suck coolant from the reserve overflow tank, the running temp just kept rising. I inspected the radiator cap, and it did have some of the seal missing, so I replaced it. Thought that would fix it, but it still will not use from reserve tank. I put coolant directly into the radiator and it runs fine, but would like to fix this problem if anyone has an idea of what to go after. I checked the hose from the reserve tank to the radiator and there's no clogs. Any help is appreciated.

[Dakota00]

Did you do the follow when flushing the system??

This is from the Dakota service manual
3.9 V6
Draining system:
-Remove radiator Cap
-Loosen radiator draincock
-Remove cylinder drain block plugs

Refill system:
-Install cylinder drain block plugs
-Close radiator draincock
-Fill the coolant system with 50/50 mixture of water and antifreeze
-Fill coolant overflow tank to the FULL mark on the dipstick
-Start and operate engine until thermostat opens (upper radiator hose is warm to touch)
-If necessary add 50/50 water and antifreeze coolant to the overflow tank. This is done to maintain coolant level between FULL and ADD marks. The levels in the overflow tank may drop below the ADD mark after three or four warm-up and cool-down cycles.

Is the radiator full?? If so, the overflow tank levels will not move. Run the truck and keep an eye on the overflow tank for the next few days and see if the level moves.

Anthony

[DMT78]

Originally Posted by Dakota00

Did you do the follow when flushing the system??

This is from the Dakota service manual
3.9 V6
Draining system:
-Remove radiator Cap
-Loosen radiator draincock
-Remove cylinder drain block plugs

Refill system:
-Install cylinder drain block plugs
-Close radiator draincock
-Fill the coolant system with 50/50 mixture of water and antifreeze
-Fill coolant overflow tank to the FULL mark on the dipstick
-Start and operate engine until thermostat opens (upper radiator hose is warm to touch)
-If necessary add 50/50 water and antifreeze coolant to the overflow tank. This is done to maintain coolant level between FULL and ADD marks. The levels in the overflow tank may drop below the ADD mark after three or four warm-up and cool-down cycles.

Is the radiator full?? If so, the overflow tank levels will not move. Run the truck and keep an eye on the overflow tank for the next few days and see if the level moves.

Anthony

Did everything except for removing the block drain plugs. The radiator was empty, I only filled the reserve tank. I ran the engine twice to see if it would use from reserve, but the temp just kept rising well over normal without any coolant movement. Upper hose would not get warm.

[riverat440]

If your upper hose won't get warm your thermostat isn't working properly

[BadAss318Dakota]

Also of there is an air pocket in the block the thermostat will not open as fast and cause higher than normal temperature untill the hot air is enought to open it to bleed out the air to the radiator on out throught the overflow tank.

[riverat440]

Originally Posted by BadAss318Dakota

Also of there is an air pocket in the block the thermostat will not open as fast and cause higher than normal temperature untill the hot air is enought to open it to bleed out the air to the radiator on out throught the overflow tank.

Although your post isn't in english I think I know what you are trying to say and most thermostats don't seal that good especially in these engines. Some jap engines have this problem as they like to put the thermostat in the lower hose and you have to bleed the cooling system when you fill it. Getting back to the original problem I have seen the tubing from the radiator to the tank have a pinhole in it and wouldn't allow the coolant to flow back to the rad during cooldown.