My temp. gage will not get over 130 degrees, really do not have much heat coming out of the heater. Is my thermostat stuck open.

 

Sounds like it to me

 

Very possible. not that hard of a thing to check, just pull it and inspect/ dunk in hot water to see what happens.

 

My engine temperature is at the correct temp (90 degrees C or 195F) but I don't get much heat either. I recently replaced the heater core when I did the Evaporator this past summer with a brass type core which is all the parts supplier had; no aluminum core available. However it is currently -10C (-23F) outside, -16C (-26F) with the windchill. Is it just too cold outside?

 

yes. replace it. look for a Stant Super Stat for about $10-12. they have more material than the cheapo $5-6 ones. stock temp is 195.

 

if the engine temp is at 195, you should have decent heat.
check that both heater hoses are hot, indicating hot water flow.
experiment with different heater settings. try Max AC, heater/foot, and defroster.
check your vac lines on passenger side of engine to firewall.
if no problems are visible, then there may be something wrong with the hot/cold control and/or the blend door under the dash.

download this service manual.
http://www.rm-indy.com/wavefiles/2001ramsrvcmanual.zip

 

When you replace the thermostat, make sure that you have it installed correctly. Note how the current one is placed. It would be extremely bad if you install it backwards.

 

that happens all the time.
sensor thingy down in the manifold,
domed side up

 

Not to hyjack here, but since I did my plenum fix and replace the thermostat with the 180, my temps on the dash show half way between the 130 and 200 mark. Is that normal for a 180? With the stock thermostat it used to read at 198.

I am thinking since it is cold here I might as well put the stock back in. Then in the summer put the 180 in. I think that how it works.

 

halfway between 130 and 200 is about 165, so that seems a little low. did you test your new t-stat in a pot of water to see where it opened. sounds like its off a little.