Coolant overflowing at radiator cap

I changed the radiator and both upper and lower radiator hoses as well as the thermostat and lower housing.
I put it all back together and added coolant to the resovoir as the vehicle was running.
I turned on the heater.
As the vehicle started to pressurize it started to leak around the radiator cap.
I took the cap off and the coolant started to surge.
It would suck down in the radiator and then surge out of the radiator.
The temp stayed at about 180 degress.
Anybody have a idea of what wrong?
I also noticed the upper hose got hot while the lower did not.

hot upper and cool lower is normal until you have saturation which only happens under load or if you let it idle for hours with no fan .... if the hoses are getting hard while the engine is still cool you have a problem.... when you say the radiator cap was "leaking" was it leaking from the seal or the overflow port ?

It was leaking pass the radiator cap gasket. There is no overflow port on the radiator.
The tighter you turned it the more came out.
I have two caps one on the new radiator and one on the coolant resovoir.
I drove the truck around the neighborhood and it still did the same thing.

I know the hoses are soft after cool down.
I can squeeze them easily.
I am thinking the thermostat is not opening

Check pressure of cooling system. If it abnormally high you might have a blown head gasket or a cracked head. The exhaust can pressurize the cooling system in either of those cases and it pushes your coolant out of system.

For what it is worth:

1. I have a Pressure Gauge on the cooling system of my ALH in the Vanagon. I have never seen the pressure exceed 10 psi. It usually ranges from 6 to 9 psi once the engine is fully warmed up. It typically hangs just below 8 psi.

2. Without all the details, I completed the last 10k miles of a 12k mile road trip without the cooling system pressurized. The engine preformed just fine and I did not lose any coolant.

I tend to agree with TDIsyncro ......... the head gasket may be blown, cracked head, impeller slipping on the water pump, etc...

Let me ask a question then?
The original configuration was a sealed radiator with the VW ball resavoir on it.
Would I not had the same problem then as do now?
I just put this radiator in with the seperate cap

Also when I took it apart It had no thermostat in it.
From what i see online the ahu thermostat is located at the bottom of the engine .
In the water pump housing.
Is there different location for a thermostat in a ahu engine?
Maybe I have two thermostates installed

Only one place for the T-stat and in all the VW in-line 4 cylinder engines that I've ever seen, it is located at or very near the water pump housing!

Excluding the big hoses and radiator (take them out of your mind), look at your system, do the small hoses provide circulation for the coolant? If not, you need to configure them so that they provide circulation.... including the very small hose.

In the car (Jetta/Golf/NB/Passat), the Expansion Tank and small hose allow the engine to purge air from the system ... and provides a means of continuous coolant circulation along with the coolant that circulates thru the Oil Cooler.

Ok I got a new thermostat and tested it and it does open.
After I got it put back together I filled it up and it started the spuing again until the thermostat opened. Once the thermostat opened it started to flow I could see it.
I put the cap on the radiator and it started leaking by the cap again.
I saw some bubbles but after that just flow.
The hose do not get hard.
I also noticed that when the fan comes on it seems to slow down the flow across the radiator.
Could I have a bad cap or do we think bad head gasket or cracked head

How do you test for pressure in the radiator?
All the tester i have seen pressurize the system and I do not want to do that it might force coolant into the engine if I have a bad gasket or cracked head

I got it fixed.
Basically I had a bad thermostat and I failed to bleed it correctly.
After watching a couple of videos I figured it out.
I am now not leaking and the bowl stays at the same level.
I am running 160% and the fan comes on and cools it to that tempature.
I have heat too.
Thank You,
For the help.