No heat.. freezing temps.. Unfortunately let it freeze a little in the cold weather, nothing busted or broke. . but after that I have no heat. The top and lower hoses are cold. engine heats up and runs a littl hot while driving but as I stop or slow down temp lowers. not getting water flow thru the heater core. Might be a simole solution to some, but we are stumped.. He thinks water pump, I say no way, its the heater core or air trapped. since this has happened drove it around 1300 miles and has not overheated, like I said before ran a little hot but never "overheated". No leaking from heater core and no "heater core smells" inside the 99 dodge ram van 1500 mach III.. Please help.

 

Do you have a valve in-line with either of the hoses going to the heater core?

 

First check the Temp Control Switch (being a 99 I have seen several youtube vids when I was trying to fix my 97 which is still cable and valves on ways to fix the blend door and other well known issues causing no heat)

If that checks out, then I would look for a broken vacuum line

Check the heater hose before the control valve under the hood (both intake which is next to the alternator and water pump supply line) for heat.

Then would check the top of the HVAC box to make sure the blend door (the control arm at top) is at the far driver (the swing goes 45 degree pass side cold to driver side hot on top of the HVAC box).

 

Are the radiator (top and lower) hoses cold after the engine has been driven for 15 minutes or are you talking about heater hoses?

How do you tell if the engine heats up? are you looking at the temp gauage or opening the hood and feeling the engine?

What does this mean... freeze a little?

Something not right or missing about the description you provided.

 

Hmm does sound odd the hoses stay cold. Blockage of some sort? Lot newer than mine. Mine has a lever type system..but at the heater core not where they come off the engine..so of course the hoses get hot regardless if heat is open or not.

 

If the engine is warm/hot and the hoses are cold, a new T-stat is in order.