When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
2nd Gen Ram Tech1994-2001 Rams: This section is for TECHNICAL discussions only, that involve the 1994 through 2001 Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
Heater core is the highest point in the cooling system, and trying to bleed all the air out of it is an exercise.
Drill a hole in the stat or find one with the jiggler valve post # 14 here. Never have the issue again! I rebuilt my hvac box, Well actually i got one from a junk yard and rebuilt that one so i could still dive my truck. You would be amazed at the crap you will find in them! I always look leaves or debris on my cowl that can get into the hvac box and clean it off. Both heater core and evaporator coil where replaced. At the time i got a aftermarket copper core, It lasted about year and started to leak. The second one i got was the aluminum one, It's been fine since i put it in about 15 years ago. I have 180 stat so it does drop the temp in the winter a bit but it's not a big deal. Once it gets to operating temp it's fine. You will turn the heat down. If you are rebuilding you box look into sponge rubber for the foam. It won't deteriorate like the replacement stuff that's available. You will have to cut your own and get the correct thickness etc but won't have to worry about it for a long time. Make sure you have enough foam around the heater core. Air can bypass it and you won't get all the heat it can produce.
I also picked up a 2nd HVAC box from a donor truck, along with a full dash assembly. I needed the lower dash to replace the one I have, which is falling apart by the day. I'm slowly rebuilding the 2nd HVAC box along with installing a new upper dash onto the replacement lower dash I picked up. Likely won't complete this swap until it warms up for an extended period, as I keep getting sidetracked by other projects, but I'm hoping that it will solve my lukewarm heating issues for good.
1999 Dodge Ram 1500 5.9 magnum. I know there are plenty of threads on the heat not working in these 2nd gen rams, though while trying to figure out why it’s not working I saw this:
I can’t find a very good diagram of the heater core lines, though these look backwards, and if they are backwards what would be the point of doing that, also could that be the cause of having absolutely no heat? I just got the truck about 3 weeks ago and am trying to get the heat fixed asap, this Ohio winter is sucking with no heat so far lol. It blows cold out of all vents the vent selector works, I can hear the blend door moving when having somebody change the temperature quickly (I’m not sure if I’m just hearing the actuator move or if the blend door is actually moving), after a 10 minute drive both heater core lines are about 142 degrees. Any ideas or thoughts about why the lines would be switched would be awesome thanks!
Those are swapped from the way mine are on my '96. I'm thinking you might have a failed thermostat or one that somebody believed the internet and put a cooler thermostat in the engine. On carbureted engines, that will give you a denser charge, but on computer controlled it just wastes fuel and you don't get any heat. Put a good, 195 degree thermostat in your engine. Do NOT use a Failsafe unit. Everyone of those I've dealt with was either failed or it failed soon after.
Now, this will seem silly, but how many miles on the engine? If it has over 120,000 miles, your timing chain may have jumped time or has a lot of slop. I had a '94 once with the 3.9. The heat was warm, but not very. Fuel economy wasn't that great for a light economy truck. It had a lot of chain slap and I replaced the timing set. I also put a tensioner for later engines in it. The chain really woke the engine up. Afterward my fuel economy went WAY up (formerly 17 mpg later 24 mpg) and the heat would cook you. My '96 had 160,000 when I put a chain set in and it had slop but it wasn't jumped, yet.
The second one i got was the aluminum one, It's been fine since i put it in about 15 years ago. I have 180 stat so it does drop the temp in the winter a bit but it's not a big deal. Once it gets to operating temp it's fine. You will turn the heat down. If you are rebuilding you box look into sponge rubber for the foam. It won't deteriorate like the replacement stuff that's available. You will have to cut your own and get the correct thickness etc but won't have to worry about it for a long time. Make sure you have enough foam around the heater core. Air can bypass it and you won't get all the heat it can produce.
