Sometimes an engine needs to burp. What happens is there is air under the thermostat and it ever opens to allow the air to burp and then the coolant to flow. Try running it without the thermostat and see what happens?

Some thermostats have a small hole or a check valve in them to let the air rise to the top. If it doesn't, I always drill a small in the thermostat to allow just a little bit of coolant to pass thru even if the thermostat is closed. I believe this helps the engine reach operating temp a little sooner. It also allows any air trapped underneath the thermostat to escape past and the fluid level to rise in the block.

 

thank you, I will try that.

for an update otherwise, I have gone out on sat or sun and picked up a bottle of prestone coolant cleaning formula. since then it now feels like my heater core is getting rad fluid again as my hoses are hot. I replaced the rad cap because the old one looks like it was thrown in the mud and then put on. this coming weekend I will be doing a multi stage flush on the system.

but for some reason I am not getting any hot air out of my blowers anymore. It was fine before the water pump and such. and since the hoses are hot it feels like its getting through.

I will be doing the flush this weekend anyways so ill see if its clogged again.

 

If both heater core hoses are hot, that system is fine. Now it sounds like your vent door isnt working. Check you vacuum lines behind your glove box. Make sure none of them are disconnected. theres also some going into your firewall on the drivers side. They are the thin black tubes

 

Don't remove the thermostat. Instead, take an old one and cut the center out of it. This way you will have something to attach the gasket to and it won't leak. Flush with water first, and then add Prestone super radiator cleaner. Drive for a combined 10 hours as per the directions with the cleaner in it. After that, flush the second time and then fill it 50/50 mix of antifreeze & water

 

Just a thought - is the waterpump the correct one and the v-belt routed correctly in order to have it turn in the correct direction?

Try getting a hold on the service manual or try having a look at the troubleshoot guide for your problem. Maybe the guy having the book lets you undisturbed with it and your phone to take pics.

As "shimaze" said the cut out thermostat will also allow for checking the flow pattern without having to wait for the temp to be up to levels where it opens the thermostat.

Could explain a lot of the symptoms.

When the engine is up to operating temp the upper hose should become warm and then hot with the opening of the thermostat. The lower will follow with a short time lag and should become warm.
Upper = hot
Lower = warm.

The hose "to" the heater core is the one leaving on top of the spider (at least as far as I know until end of 1990's- could be different on newer ones. Normally tapping for hot water at the spider as there is the first hot water.

The older models up to 1994 had two temp sensors - one just for the "HOT" light, while the other served the temp gauge.