[01 Off-Road Ram]

I noticed this problem last winter. The heat in my truck 01 Dodge Ram, is only hot when I am accelerating. When at idle or coasting, the heat noticeable gets cooler. The colder the weather, the more drastic the change. Last February, I had the cooling system flushed, the heater core flushed directly, the thermostat replaced, the fan clutch replaced, the water pump inspected. Still the same problem. What is going on here? They also told me that my truck supposedly doesn't get up to proper operating temperature according to my gauge. Then they withdrew that statement by using an external thermometer and said it did. My gauge always points to a little bit before 210 and they said 210 is the normal operating temperature. I'm pretty sure that this problem is not related to coolant level as it was not related last February.

Please help its only going to get colder! :VHOT:

 

[LoudRam]

Well a stock t-stat is 195 so your gauge reading just below 210 is right on the mark. My heat was luke warm a few weeks ago. I had a leaking heater core. There was a good chance it was clogged too even though I just flushed it a few months ago when I replaced my plenum gasket. My heat is great now with the new core and I have a 180 stat

Double check your coolant level. Listen for a bubbling sound coming from behind your glove box. That's the classic low coolant sign.

Your core might be getting clogged to the point where you can't flush it out. Try taking off the hoses going into the core at firewall and try flushing it out that way. Prestone also makes some heavy duty flush.