Hello again,

My wife reported the other day that the van wasn't blowing warm air, even though temp.gauge showed vehicle was sufficiently warmed up. After playing with the sliding temp controls, and cycling the power I received warm air. The next morning, had a very cold drive into work (short drive) as the same issue repeated itself. Given that the problem is intermittent, what should I be checking ?

Thanks in advance,
Rhino

 

Did some more testing, and found that it's not blowing hot air until the vehicle is warmed up, and driving. Seemed to be related to pressure, as when the vehicle stopped at a set of lights, the air cooled down. Also noticed that the 're-circulation' button could be activated while heat was on.. I previously thought this was not possible.

As I was about to pack it in for the night, noticed fluid dripping.. here are some pictures. Are these heater related lines ?



[IMG]local://upfiles/48987/53CA04A29CA04E5ABFB7C2D54BA2C56B.jpg[/IMG]

 

I realize this is a 4 year old thread.. but it never hurts to try.

I'm having this exact same issue. Did you ever figure it out? 2003 GC, intermittently blowing cold air and hot air. Seems to blow cold air once you come to a stop, and start blowing hot air while we're driving.

Just started noticing this since it's been freakin cold here in Calgary, Alberta the last while. It's been hovering around -25C (+/- 5C) for the last 1.5 weeks.

 

Have you replaced the thermostat?? The t-stat maybe stuck open,

 

Not yet. Actually, I worded my post wrong - I just noticed the problem tonight actually. But was thinking the cold temperatures over the last 1.5 weeks may have contributed.. or made it more noticeable.

Did some reading in my Haynes manual and that's what I think is wrong - thermostat stuck open. Engine is up to temperature and when I grab the upper rad hose it's still cold. I tried opening the radiator cap and got a splash of coolant.. which was cold still (thankfully for my hand).

Any chance a bad thermostat would cause an intermittent CEL, but no codes? Cause that's been happening for the past few months as well.

 

It could, but so can a loose ground cable at the battery. I would still replace the t-stat.

 

I am presently having all these symptoms, poor heat at an Idle, better when excellerating, my motor is the 5.2 in a 99 Ram 1500. I checked the coolant level, I installed a new thermostst from Chrysler, I checked the flow of coolant through the heater hose, by removing the return line at the water pump and bumping the starter, it has good flow. I checked the movement of the Blend door and the effects of all the different settings on the heat/AC controller, this all seems to be moving correctly. I tried the CLR in the Heater Core for 30 minutes, I tried circulating Prestone Super Flush through the heater Core itself the flow is Good. I then installed a flow restrictor in the return heater hose, the hose is a 5/8" diameter and I put a 1/2" restirctor in there. I put a full size cardboard in front of the rad with a 6" diameter hole in the center. Nothing seems to help, I do suspect the heater core although the flow is good, perhaps the flow is around the outside of the core and not in the center area of the core??? I also suspect that the engine does not heat up enough?? Is it possible that the Catalytic Converter is not function properly? Possibly the A/C is not functioning as it should?? I am determined to find out what is the problem. Colin

 

colin your symptoms sound like a bad water pump or plugged heater core.
after you changed stat are you positive you burped out all the air in the system?


with the cardboard on the rad you should see temp gague a little higher than usual, is this the case?

the lack of heat wont have anything to do with the CAT

 

Colin
I can say that I ran the engine for sometime with the rad cap removed and I did not actually see any flow through the rad, I am not even certain that the thermostat opened.

I suggested that Cat as the culprit because I thought that one of it's purposes was to create backpressure and therefore heat with in itself to perform it's burning off process. This used to be the job of the Heat Rizer Valve in the older vehicles. What you have suggested, the water pump or the Heater Core are two definate possibilities, the water pump would not be to difficult to change, I may try that next. Thank You hemi4spd.

 

I have since tried the truck on the highway, with the full cardboard, the engine temp was over 100 Celcius so I had to remove the cardboard, this still did not make as much heat as I thought it should. So I went a head and changed the Water Pump, the By-pass hose, the Lower Rad hose, the heater hoses and the Belt tensioner and pulley. All of this and the poor heat is still the same. So now I have ordered the Heater Core and the A/C Evap. and I am going to change both these cores at the same time, I hope this will makes Good Heat. Colin