Not A body - low heat in my 98 Ram 1500

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Mopar to ya

Mopar to ya

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I have a 98 Dode Ram 1500 with a 5.9. I have never had good heat. In fact, if I turn the fan past the second setting, the air flow negates the heat and it blows cool. The reason I am bringing it up now is that this week in the shop we have had two Dodge's with the same problem. One we had carte blanche to fix. The t-stat was working. I can feel the lower hose go from cold to hot at around 200 degrees. There was a lack of coolant flow and the heater hose temp difference was more than I liked. I got 105 degrees heating at the vents in the shop. We pulled the water pump, expecting a bad impeller. No dice. The impeller was fine, but the bypass was very blocked. Cleaned the bypass put it all back on. Way better flow. Got 135 degrees at the vent in the shop. Backflushed the heater core. got 165 degrees at the vent in the shop. Drove it outside in 30 degrees weather for a mile. By the time I got back I had 88 degrees at the vent. The heater hoses at that exact moment were 165 degrees going in and 128 degrees going out. I looked online and this is a common problem. Everyone with a Dodge truck seems to complain of this, but with hundreds of complaints, I find no one who ever solved the problem. I am going to flush and backflush my heater core on my personal truck with CLR and see if that helps. Anyone run into this before and have a solution?
 
A common issue with these is the fact that the heater core sets really high compared to everything else. I learned that if you separate the hose on the high side of the heater core and get the trapped air out of the heater core that it fixes the problem many times.


I use my radiator pressure tester to force the air out of the heater core. You have to hold the hose coming off the heater core up and clamp off the other hose that you separated it from.
 
I fill the hoses and reattach them full of fluid. I am considering using the old vacuum filler that sucks the cooling system into a vacuum first and you fill the fluid through it with negative pressure. Otherwise we lift the front end on a hoist and bleed them with the front end higher than the heater hoses.
 
I just got thru doing this, after checking thermostat etc.., what I found was when I first went to flush the core, I went with flow first, and there was definately a restriction,, 1/2 flow thru it,, I then backflushed it,, and it spat out some thick crap, I have no idea what,, tried with flow,, still not quite full flow,, backflushed again,, and it spat something else out, repeated flushes a coupla times, has worked really well the last 3 week ..

hope it helps
 
My Brothers Ram has this exact same problem, and I also noticed that the hose temps were way different.
I'll tell him what you guys ran across, but we were planning on flushing it anyway.
(trapped air is nice to know)

Thanks
 
Dodge must of fixed before '99. I didn't have this issue when I had that truck, owned for over 100,000 mile no issue with heat.
 
Doing the CLR on mine. I took the hoses off, blew light air pressure to get all the fluid out, and filled with CLR. I'll give it a half hour or more and flush it, then fill it with CLR again and then flush it the other way. I'm crossing my fingers but not expecting much.
 
Google it. the flaps in the heater box are notorious for breaking and then the box doesnt switch to heat. In trhe summer the a/c isnt as cold as it should be either. Every one wanted a recall but it didnt happen. Cheap bastards.Heres the fix.[ame="http://www.youtube.com/watch?v=KAclL84Qq8E"]Dodge Ram Air Door repair Heater AC HeaterTreater - YouTube[/ame]
 
I did google it. Never saw that post, but I did take the dash out so I could see the blend door. It opens and closes. Is it closing tight enough? Maybe not. I've seen hundreds of Chrysler products with problematic heater boxes.
 
..........Look up for ur year.......the heater treater fix helps a lot but the heater core is plugging up and needs replaced, flushing helps too but does not get all the crap out.........kim.....
 
Check out this video also, it is for your bodystyle truck and having the same problem as my '98 ram.
[ame]http://m.youtube.com/watch?v=_gSwbuJHHXM[/ame]
 
daredevil said:
Google it. the flaps in the heater box are notorious for breaking and then the box doesnt switch to heat. In trhe summer the a/c isnt as cold as it should be either. Every one wanted a recall but it didnt happen. Cheap bastards.Heres the fix.Dodge Ram Air Door repair Heater AC HeaterTreater - YouTube
Click to expand...

I'm not sure if this applies. I have a 1998. I can remove the instrument cluster bezel and look down and see the blend door open and close. I can't get a hand in there to say if it's tight enough, but it does work.
 
duster360 said:
Check out this video also, it is for your bodystyle truck and having the same problem as my '98 ram.
http://m.youtube.com/watch?v=_gSwbuJHHXM
Click to expand...

That is a pain in the *** set up if you ask me. He is right, the heater core inlet is the high point of the cooling system. I had a lot of options to bleed it well, but the one I chose was to lift the front end until the radiator cap was the high point and I bled it well that way. I have a tool that sucks the entire cooling system into a vacuum, and then you stick a hose into coolant and open the valve and the vacuum sucks the coolant in with no air able to enter the system. It's a PIA and if you have any leaks it will not work.
 
Okay, and the final analysis. I filled the heater core with straight CLR and let it sit for an hour. I flushed it both ways with a garden hose, then filled it with CLR again and let it sit two hours. After flushing it clear both ways again, I filled the core and hoses with coolant to limit the amount of air and attached all the hoses. Taking the easy way out, I lifted the front end on the hoist until the radiator cap was higher than the heater core inlet and bled the system until the t-stat opened. I had 130 degrees from the vents while in the shop. When I drove it home, the heat stayed strong and hot and did not fade like it used to. It got so hot that for the first time since I owned the truck (2 years) I turned the heat down from full hot. Granted it was 35 degrees outside, but it was the same temp this morning and I had little to no heat. Tomorrow will be a good test. It is supposed to be 8 below zero with 70 below wind chills. I am curious what kind of heat I'll get on a day like that! Bottom line - CLR flush seems to have worked for me.
 
Got the same issue with my -98 Dakota 5.2. Haven´t checked the doors to the heatercoor yet.
School me on this one, what do you guys mean with CLR?
 
2Q==
pic didn't work? just google it
 
So how was the heat on Sunday???
C
 
My 2001 Dakota has heater problems or no heat I put in a new 195 tstat dident help that's as far as I got .
 
Got the same issue in a 98 breeze..freezing my nards off,new pump fluid and hoses think maybe in the dash,never done it before in 250k of driving[motor has 100k,and yes it's been douched]
 
Not fixed after 99.

I've been battling this on my 2000 Dakota for several years.

This year I tried something different.

I discovered the nozzle of my pressure washer just barely fits inside a 5/8 heater hose, and I power flushed the heater core both ways.

It took almost an hour, going back and forth for 5 min at a time before the water ran clear both ways.

It's still not 100%, but at least I have some hot air out of the vents.

I also put in that corrosion inhibitor, instead of water to mix with the anti-freeze.

Prior to this, I'd flushed it six times in two years, both with and without prestone or peak flush.
 
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