Hey to all on here..So I have an 08 ram Hemi
Suddenly I have no heat at all and its the coldest its been in a long time..I have been searching on here for well over an hour but the search function sucks big time. So please forgive me if this has been constantly asked..I cant find anything about it. So here whats going on..For about the last week or 2 I have noticed a noise from the heater core area sounds like leaves blowing or trickling water when i hit the gas, but only when the engine was cold. Always had good heat though. Now these past 2 days there is int that much heat.. It gets warm and blows a little heat then it will stop and just blow cold air. I opened the hood and checked the hoses that feed the heater core and they both were the same temp, warm to hot. Im not a mechanic by any means but doesn't that mean that there is flow through the heater core? What else can it be? Any help would be awesome as im lost with this one..

I also should add that the rad fluid level is good. This truck has been through 2 water pumps under warranty..

 

Did you add coolant? How much? What engine? If it was really low, could be you have other issues.

 

Sounds like the vacuum reservoir is not holding a vacuum.

If the fluid level is good, check the vacuum lines, as they actuate the blend doors/heat controls.

I believe default mode (total loss of vacuum) is cold air blowing on defrost only.

At least the Jeeps are, not sure on trucks but there's some great knowledge on the forum, if I'm wrong they will help you out.