1998 Dodge Truck

RCJ

MEMBER
1998 DODGE TRUCK

Heater problem
1998 Dodge Truck Automatic

I have a 98 dodge ram 2500 truck with the 8 liter v-10 engine 2 wheel drive I have great ac but the heat isnt so great, ive replaced the thermostat, water pump, and temp control switchs in the dash the ones that control ac, heat, defrost and floor when the temp outside is in the 50 degree range the heat seems warn any cooler and it doesnt seem like its working if you put your hand by the floor vent it seems at most luke warm. Top of the heater core gets real hot can only touch for a second or two. The hoses in and out of the heater core are both hot now I know that the heater box is suppose to be the same from 1995-2002 but in a couple things ive seen there is a little electric motor on passenger side and a plastic sleeve that opens and closes a blend door my truck does not have this it appears a cable on the top of the heater box opens and closes this door. Im not sure if this was a fix to a certain problem from the dealer or if my heater box is different. My heat used to get real hot but not anymore and it seems this is a common problem and nobody can figure this out please help.

7 Replies

CH112063

MECHANIC
1,320 POSTS

No, most had a cable except full ATC system, that I've seen. If the cable is holding the door all the way, there are only twp possible causes. Air or core. How many miles?

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Monday, November 16th, 2009 AT 9:19 PM

RCJ

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There are aprrox 130,000 miles on the truck the radiator is about one and a half years old it was put in by the dealer. By air do you mean air flow? Because the blend door is opening and closing but im not really sure how far it is suppose to move. I did just replace the radiator cap today a friend recomended trying that and I figured what could it hurt it was only $6.00 and I think mine was the original cap. It seems to me like this is a common problem with these trucks is that true?

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Monday, November 16th, 2009 AT 10:33 PM

CH112063

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Yeah it was a common problem. I meant air bound or air in the core from pressure leak. And replacing the cap was smart thing. It just has a full open and full closed lever, the cable is supposed to self ad just so if you can see where it connects(the cable) at the lever remove it by squeezing the plastic clip, remove the other metal clip with the cable. Then move it by hand, if it is not any better and both hoses are hot it may be just a bad core or sometimes a air leak in the cooling system(head gasket) will cause bad heat, see if it gets any better if you rev the engine while holding the lever in heat position.
If your not losing coolant for any unknown reason, removing the box(heater/ac unit) is necessary. Depends on mileage and engine work you have done. Ok

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Tuesday, November 17th, 2009 AT 10:27 PM

RCJ

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The truck isnt losing any coolant, and I did check to see if I stepped on the gas if the heat did get any warmer and it does seem to get a little warmer as soon as I can im going to try and flush the heater core out with a radiator cleaner ill just by pass the core and let the chemical sit in it for a little while then flush it with water for 15-20 mins and see what comes out. If you have any other input id greatly appreciate it im laid off and cant afford to take it into the dealer. I didnt take the cable off yet but on the bottom of the heater box is a rod I believe is half mooned in shape and when I adjuster heater switch from cold to hot I can feel it rotate. I will disconnect the cable like you told me to before I flush the core. The dodge dealer a year or so ago replaced alot of my ac stuff could they of done this because I didnt have this problem til after the ac was fixed the heat was fine the winter before my ac went out then the winter after ac was fixed heat gave me problems. I really dont care how it happend I just want to fix it.

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Wednesday, November 18th, 2009 AT 3:30 PM

CH112063

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What work was done to your a/c? I bypassed mine, like your talking about, I haven't replaced the core yet but I am going to do what I have done to my other car, put an outside unit in(long story). I "engineered" it myself.
If you have high mileage this is the problems I have encountered, air in core constantly reducing heat output. The water pump or hetater control valve was not right, or some one was in the unit and did not seal the top of box, or the cable was adjusted wrong from age, failure, or it was broken. Theres other problems possible with other doors. Accidental.
The fix, cheapest, is what you are doing.
Hope it works. The cure is time consuming and requires tools(expense). Remember, your radiator was replaced, if it was for being clogged, than your doing the right thing by trying to clean it out. Excuse my inability to communicate very well. I repaired too many cars/trucks one after another, bumper to bumper, and worked alone, without explaining or using a keyboard. Also had a 'nervous stress syndrome' you know "breakdown", but this was a common thing that happens every 10 years or so, on flat-rate. Hope your ok, I am always around, still plugging. Ok If you have heat in, and out, of the hoses, it should blow hot if the core is not less restricted(but not blocked), the door is leaking air flow, or there is pressure in the system, air leak, and also not enough water pump pressure(flow). Do you understand me just a little Mr. Rcj? Your doing the right thing.