Sunday, January 27, 2013

Dodge Ram has No Warm Air


Thermostat tested good and coolant level is fine.Also there is no engine overheat issue noticed while driving.

It Does get slightly warmer turning it from full cold to full hot.

At our Auto repair garage we have seen lots of such similar and relative cases,when AC and heater both functions but not completely and correctly.

Your case is also one of them.

In your case also the heat is there but not completely warm its getting.

So suppose its ineffective to control temperature at all then i believe the problem is related to  blend door but as per what you described your problem I really don't think that is certainly in your case. Because when turning from cold to hot you get bit of warmness.

The blend door is the door in the heater box that controls temperature. It is driven with an electronic actuator controlled by the control head on the dash.
In your case you receive bit of heat,these confirms that blend door is functioning.So this tells us that the door, control head and actuator are most likely ok.

Also in your description you mentioned that coolant level is fine.
I exactly dont how you checked the coolant level.But if you are confident that its full then on some cases its leaking coolant,also get the coolant leak issue confirmed by getting the coolant line pressure test done.
On some cases we see that problem results due to air in heater core causing these.

If air is caught in the heater core it leads to lack of heat problem. Air can be stuck either from a leak resulting in low coolant level or lack of bleeding the system after a cooling system repair.

But if coolant level is tested full and you don't hear any gurgling sounds from the dash on acceleration then you can rule out air in the heater core.

On such types of problem mostly the possible reason is low coolant or faulty thermostat or issue with blend door or faulty blend door actuator.But if all these most common possibilities if checked ok,then

Most probably on your case its a restricted heater core. Over time dirt,dust and corrosion can develop on the specific cores within where the coolant passes and it puts a stop to coolant from flowing appropriately.
In the same way if there isn't sufficient hot coolant flowing by the core then it can't properly heat the air. As your vehicle model it uses modern heater core brands. And as per modern day heater core design you cannot always depend on being able to feel a temperature variation between the hoses anymore.

To correct these problem i suggest flushing the heater core and that should take care of your problem.
Inspect and clean the heater hoses correctly.There will be two hoses.
The heater hoses located at the firewall and follow them forward. One will go to a tube at the water pump, remove it at that joint. The other hose goes along the right valve cover and will have a coupler inline, remove it there.Before removing the hoses understand its positioning.Refit it same way as it was fitted before.

For flushing,servicing and cleaning the heater core follow the procedure:---

Run water through the heater core using a garden hose, watching the water flowing out.At beginning the dirty water will flow out,let it flow. Once it starts to flow clear water then stop and flow water in the opposite direction. When it starts to run clear again switch back to the other direction. Flush till you get any dirty dustiness in the water.

Then re-install the hoses, bleed the cooling system and you should find that your heat is back.Please make sure no air gets trapped or remain in the heater core.Bleed the cooling system line completely.

These details will help.

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