2000 chevy blazer no heat and does not seem to be any coming from thge engine.

No heat from dash or floor blower

Check your anti-freeze level if its low fill it up to the proper levels(radiator and overflow bucket). If its low then look for a leak. If its not low then it could be the thermostat.

I'm going through this with my 99 Blazer right now.. My engine temperature barley gets off the 100 mark on the gauge. Went through the system, stat is good, no leaks, heater core good, system is full, but no pressure builds. I did the old cardboard in front of the radiator trick (covered 2/3 of it) and got the running temp up to around 160. Bingo, I have heat :) If you search forums it seems to be a common problem for these vehicles with no explanation for the low operating temps.

Hey Mark have you ever flushed your radiator or replaced the radiator cap?

Yes I have. System flush, New cap, replaced water pump also. I ran it with the cap off and could see that there is flow. System looks clean and full.. I'm stumped!!

Yea that is strange! For shits n giggles I would put in another thermostat. Maybe a 195? Sometimes parts can be bad right out of the box, happens more times than I care for. Then test the old one to make sure its not stuck open.

Thanks, yes. That was going to be my next move to put a hotter stat in.

Great minds think alike, huh? LOL! I hope it fixes your problem. Heat is must here where I live cuz its 10 right now :(

My first thought was the thermostat and fluid levels. Then make sure the heater box opens and you get hear. If you cover the radiator to raise the temp and you get heat in the cab, than it is not the heater box or trap doors. It may be the thermostat stuck open or fan running all the time. It also may be the fans are running all the time. My second guess would of been the controls to turn on the heater or the heater box is plugged or not getting flow into it, but what you said that may not be the issue.