Alright basic info, 2001 Dodge Ram 1500 5.2 135000miles
my truck heater is far less than satisfactory, i have my own opinions as to possible sources but would like the forums wisdom.
With heater on full blast, and max heat, i get cool air at best, this changes for about 10 seconds periodically. the only thing i can see that changes in those 10 seconds is my temperature gauge goes from 240ish :/ back to 210. then i loose heat again. I've read several forum posts already but am trying to decide which options to try first.
thank you in advance for your help.

 

You might need to burp the cooling system.

Put one side of the front on a truck ramp, take the rad cap off and leaving the truck running with heat on full blast, watch for burps, refill coolant as needed...

 

Flush the heater core. Worked wonders for mine. You should definitely be getting heat with those engine temps. It's cold here, but I was able to run a garden hose via my washer water hookup for the procedure. It's really pretty quick if you have the right parts.

 

i will try both of those, what else is recommended? also side note don't know if relative but the ac works fine.

 

If you verify the heating/cooling system is working fine, no clogs, than you might need to check out the thermostat..

 

Thermostat sounds like it is sticking, but, that isn't your heating problem.

Along with burping the system, and backflushing the heater core, make sure your temp (blend) door is working. It is electrically controlled on your truck. There is a little motor on the bottom of the heater box, that controls the door, there is a coupler between it, and the axle the door is on, that likes to crack, and break, and the door can then flap in the breeze. Do a google search on "heater treater", and check out the dodge section. Most enlightening.

 

i'll be honest i was really hoping you would weigh in on this heyyou, i had a question directly for you i have read those posts but didn't want to jack a 2 year old thread. my question is what does the cold side of the thermostat control on dash actuate, it just seems in my head that if the heat isn't controllable why would the cold be. obviously a novice question but i don't know the answer. also if that plastic piece is cracked and "flap in the breeze" why does the heat correlate with the thermostat opening?

 

Coincidence?

The door may be stuck in the cold position, or, you may have more than one problem. Quite honestly, getting that little motor off to check the coupler is a PAIN. There are only two screws, and an electrical connector.... but, one screw is on the back side of it, and you may have to cut the carpet to be able to get it out. (have a look, see what ya think. One member was able to get the screw out simply by using one of the little z shaped screwdrivers...)

Think I would check everything else first.

Verify you are getting flow thru the heater core. When engine is up to temp, both hoses should be pretty darn hot.

If that's ok, you may still have an air bubble in there, or a clog. Backflush next. You can disconnect the passenger side hose at the coupling in about the middle of the valve cover.

Disconnect the other line at the steel pipe going into the water pump. (this is the return line. coming FROM the heater core.)

Run water at some reasonable pressure backwards thru the heater core, and see what kind of crap comes out.

Once it runs nice and clean, hold the return line up above the level of the heater core, and prop the inlet line against something to have it pointed up. Run some more water into the return line, until it flows out the inlet line. Reconnect both lines, trying to keep as much water as possible in the lines. (to prevent the air bubble from re-forming..... it's a right biatch to get out.)

Try your heat again.... See what ya get. (this worked EXCEPTIONALLY well on my truck. The heater will burn you out in less than 10 miles.)

If you STILL don't have heat, time to drop the little motor, and see what the coupler looks like.

Edit: Keep in mind, with the engine hot, the cooling system will be under pressure. If there is pressure, do NOT open the cooling system until it has cooled off sufficiently. You REALLY don't want a shower in hot coolant. Most unpleasant experience. (and no, I have not done that, but, know people that have..... they have permanent scars from the experience.)

 

Checked the hoses, both were warm to hot, after about a 15 min cool down with single digit outside temps.does that eliminate any possibilities as to problems?

 

Not really. On mine, both hoses were hot, but, the heat sure wasn't. After backflushing the heater core as listed above, the heater will now cook me out of the truck pretty quickly. MAJOR difference in heat output.