I got a chance to look at it today.
I sucked the overflow dry then I let it idle with the cap off and coolant kept overflowing so I replaced the cap and and let it warm up then flipped the lever on the cap then safely removed it, with gloves on and a face sheild on....etc..... I watched the coolant, it dropped as if the thermostat opened, while idling but It never looked as if its flowing. I grabbed the upper hose and squeezed it several times and a huge amount of air kept bubbling out.
I also sucked out about a pint of coolant directly from the radiator but it kept coming up trying to overflow. Im kinda stumped, never had this happen before. There are no bubbles while it is idling unless I squeeze the upper hose.

Could this be air in the cooling system?

 

Does this van have the rear heat? That is the only thing I can think of where the air is coming from, minus the possibility of a leak in head gasket to the combustion chamber.

 

Yes, but the heater core leaked a long time ago so I bypassed it, same with the front heater core before that. No heat, Im cold, LOL.
The coolant and oil dont look discolored, They look like they should.

Could it be that the hoses that are bypassed are holding air and that is getting into the cooling system?
Is there a way to bypass the rear heater core closer to the engine so there are no long hoses holding air?

Thanks.

 

Run a piece of heater hose from the port on the top of the intake manifold right behind the thermostat to the second port on the side of the water pump, right next to the one that comes from right next to the thermostat. If you're still getting air in the system after that then you have a leak somewhere.

 

Sounds like an obstructed radiator to me. 99% of the time leaking heater cores mean the coolant was neglected at some point causing corrosion. Old coolant becomes corrosive, and that can do really bad things to every part of the cooling system. Was the radiator ever replaced?

 

I don't think mine was it looks downright nasty!

 

Mos, Will this eliminate/bypass the rear heater core tubing?


Yes, it was a while ago along with the pump at the same time. The PO kept it in very good condition, Although... I have neglected it quite a bit .


I am considering installing another front heater core but I would like to eliminate the rear heater core tubing from the mix weather the problem is the radiator or not.

Thanks.

 

What I wold do at this point it, do the combustion leak test to eliminate that it might be head gasket problem. Next i would replace the thermostat Again.. At least pull out the new one and check it in boiling water to make sure it is opening at the correct temperature.. This requires a thermometer to read the temperature at which the thermostat is supposed to open at.. ..

I replaced the thermostat on my 85 e150 and it seems like within a month it was overheating when pulling any small grade.. at one point it overheated within a mile from my house on a flat. I stopped and cut the engine off sitting there thinking what to do.. When I started the engine again the temp went to normal... IT had stuck closed. When I pulled the new NAPA thermostat out and tested it in boiling water, I could see that as the temperature was rising, the thermostat was opening at an angle and binding up to the point where it would not open all the way.. SO I was getting some flow but not enough to cool the engine under a load.. Replaced it again and all was fine...
At least take it out and try it without a thermostat so see if you have flow in the radiator.

As the water flow is from the bottom of the radiator, through the engine, then back to the radiator through the upper hose, when squeezing the upper radiator hose, it is possible to suck some air back up into the hose under certain conditions. If upper radiator hose connection is at the very top of the radiator and the radiator is not completely full.
If the van is sitting at a angle where air at the top of the radiator would move to the upper hose side.. When you release the hose, it would suck the air back in..
If the flow is restricted due to a bad thermostat or clogged radiator, you would notice the air bubbles a lot more because of lack of full water flow in the upper hose..
The other thing that can cause air in your upper hose would be combustion gas from the cylinders if you had a bad gasket or cracked cylinder head. The air would actually be combustion gasses..

Any air in the heater lines would eventually work their way out.

 

Thanks for the advice everyone.

I could not get much done today so I took it for a test drive, only about 3

miles and after about two miles the gauge started to move closer and

closer to the red overheat area on the gauge. I got home before it

overheated and the upper hose was rock hard so I let it cool a bit and put

on my face shield and got some towels and pulled the lever on the cap to

release pressure opened the cap and started it up. There is no coolant

flowing at all, Its just sitting there like the pump is not working or there is

a blockage somewhere. I am sure I installed the thermostat the right

direction. Next chance I get I am going to take annas advice and pull the

thermostat, and run it to see if coolant is flowing without the thermostat, if

there is no change then I guess its the pump or a clogged radiator, I am

almost hoping I installed the thermostat backwards...... LOL.

Thanks.

 

Just remember to put the pointy part facing the front lol I have to think about it every time I do one lol

 

If I still get no flow with the thermostat removed, how do I determine if the problem is the radiator or the pump?

I have not had time to work on it this week.

Thanks.

 

Removing the thermostat just rules out the thermostat, nothing else.

You can pull the water pump and visually inspect the vanes, or pull the radiator and try to flush water through it. My money is on the radiator.

 

Honestly, it'll be your pump. I had to replace mine after I did the same to determine what my problem was. I opened mine up during the rebuild to make sure the impellers were in good condition, but when I put it back on it wasn't flowing at all so someone before me put on a CCW rotation pump and that's why it wasn't flowing at all.

 

Yea, I dont think its the thermostat because it did the same thing with the other one, but just did not get as hot because I did not drive as far.
I am considering replacing both the pump and the rediator and be done with it.
I dont want to do the head gasket test because The coolant and oil look good and If it is the head gasket I cannot afford to replace it

I might just pull the radiator and test it first then if its good then move to the pump.

Thanks.

 

I concur
I've only seen 1 pump have the vanes so rusted out that they were gone and I literally replaced hundreds (if not over a thousand) when I was a full time shop mech. It's very rare. I never saw one rust away on a race car.