Overflow tank fill up

[6.5stayinalive]

I've had the truck for almost two years, and for the last year at least I've noticed that the overflow tank is always almomst completely full, hearing bubbles after driving it are common, but i didn't think much of it.

Recently I've noticed that the radiator seems to be slowly pumping coolant out of the radiator and filling the overflow tank, under normal driving, it seems like I have to put another jug of antifreeze in every week or two.

Any information regarding this would be appreciated.

 

[NVW]

Either you have a bad head gasket or a crack in a head or block.

 

[orrum]

I had a leak in my radiator that was in the very bottom n ran over to the fenderwheel area n dripped and nobody could find it n we thought cracked head etc. Then I hooked to a trailer full of horses n ran the pee out of it n I found the leak!!!! LOL What a relief, bough a radiator then, cheap compared to the alternatives. My advice is to get it pressure tested n if you see nothing let it sit for a good while to find the tiny leak!

 

[WarWagon]

The cooling fan will vaporize and small leaks from the radiator. The heater fitting is famous for leaking on the t stat crossover.

The radiator cap, that no one ever tests like they should, may be leaking or not holding pressure. Heat soak can pop off a weak cap after shutdown. Had a new cap do this to me from GM. Also had a new cap suddenly blow off and cost me an engine from shock cooling.

Cold you want to start with no pressure. Start the engine and see how fast the cooling system pressure builds up. Quickly means a combustion leak from a crack or gasket failure. Is the engine making oil or oil consumption suddenly quit? Have you popped off the CDR and looked for moisture in it?

 

[6.5stayinalive]

The cooling fan will vaporize and small leaks from the radiator. The heater fitting is famous for leaking on the t stat crossover.

The radiator cap, that no one ever tests like they should, may be leaking or not holding pressure. Heat soak can pop off a weak cap after shutdown. Had a new cap do this to me from GM. Also had a new cap suddenly blow off and cost me an engine from shock cooling.

Cold you want to start with no pressure. Start the engine and see how fast the cooling system pressure builds up. Quickly means a combustion leak from a crack or gasket failure. Is the engine making oil or oil consumption suddenly quit? Have you popped off the CDR and looked for moisture in it?

I started it this morning after sitting all night, popped the hood and checked the overflow tank and it wasn't bubbling. My buddy works at a local Ford dealer as a tech, we're going to pull the truck in and pressure test it.

 

[GM Guy]

check it when its warm. heat expands, cool contracts, tiny cracks may not show up when cold.