please HELP no heat!!!!

[dirtmod0]

Engine 350 steel heads and water pump. The engine is new. The long block is a 1998 with vortec heads.
I have installed a new standard flow water pump and tonight i installed a 195 thermostat.
the ploblem is the engine will warm up and stat opens and the shuts and the heat goes away I can not keep steady heat , I am judging this by the air flow I feel from the clutch fan. I have have no heat coming out of the water pump outlet going to the heater core either. I am stumped and really need some suggestions..
Please Help Me!!
1980 k10 short bed

[ccz145a]

Post a pick of the heater hose connections at the front of the engine.

Just a thought, but what if the builder used rags to keep debris from falling into passages and forgot to remove them?

[VileZambonie]

If you have vortec heads which intake did you use? Did you run the bypass hose to the waterpump? You should have the hose going from the top of the intake manifold to the bottom of the core. Then the top of the core should run to the radiator tank.

[dirtmod0]

You both hit the nail on the head. I had the one line hooked up wrong from the water pump, moved it to the intake and good to go now..

[VileZambonie]

What do you have going to the waterpump bypass? You should have a hose connected to the intake also for the waterpump bypass. Your intake should have provisions for a nipple in the front of the manifold.

[eventhorizon66]

Did the late model blocks not have the waterpump bypass built into them?  Mine does.

[dirtmod0]

I have one hose at the rad. and the other is at the pass. side of the intake. The water pump provision is blocked off. The intake is a Edelbrock Performer for the vortec heads.
Thanks again for your help

[VileZambonie]

Did the late model blocks not have the waterpump bypass built into them?  Mine does.

The bypass runs from the waterpump to the intake manifold. The vortec plenum is different.

[355shortbed]

i have a question about my truck having no heat. it is a 77 k-10  4 speed, i have my upper radiator hose going to the intake and the lower going to the water pump, this is how it came origionally. i only have replaced the intake with a weind alum. and a new heater core but still blows cold air. does mine need the bypass to the water pump??

[VileZambonie]

run the heater hoses the way we said and make sure you have a good thermostat in there. Are either of the heater hoses hot?

[355shortbed]

yea they get hot. but i get cool air,not sure if they are hot enuff though. i have a new 195 thermostat. the flaps are in the correct position, when i replaced the heater core, would it matter that much if the insulation around the flaps got cleaned off?? i would think that it would still produce some kind of heat.
       So i need to run a hose from the intake to the water pump, and switch my hoses around. My radiator dosent have a nipple for a heater hose being a manual, it has a plastic plug under the radiator cap about 3 inches down, but none of the brass fittings we have at work fit, it looks to be 1/4inch 1/8 hole.
       I dont know its colder than a frozen bag of peas here! and i like hearing those flowmasters sing but its to dang cold to drive it without heat.

[VileZambonie]

No you will run the return hose to your waterpump. you have no seperate bypass hose. Check the blend door in the distribution plenum if the core isn't clogged.