99 Ram still no heat

So after replacing the water pump, t stat(3 times) and fan clutch I was able to somewhat solve the problem of no heat. I do get a little heat on the low fan speeds but it gets cooler if I go to the third or fourth positions. This is ok when it's 30 or 40 outside but on days like today when the high was 4 degrees it's almost like having no heat at all. I know the heater core isn't blocked(both hoses are hot). The coolant is clean and full, I really don't think the heater core is leaking. The only things I can even think to check are maybe the actual vents or other parts under the dash. Not sure where to begin here, or if there is anything anyone can suggest but I need heat, at least more than this. I've tried running it on the max ac setting rather than defrost but it only made a small improvement. Any help is appreciated, I'm getting desperate.
Thanks!

On my 95, the blend door under the dash had the cable attaching point
broken/unhooked. Shop rolled the dash back and jury rigged a repair to it
and it's been working fine every since.

Jay

Are both hoses going into the firewall where they connect to the heater core hot?

Are both hoses going into the firewall where they connect to the heater core hot?

They are hot enough that I can only grab them for a few seconds. They seem hot enough to me, but I've also heard that you shouldnt even be able to touch them...
Thanks!

I am having the same problem in my 98 Dodge Ram and have done EVERYTHING to repair the problem. I was informed to cover the radiator with card board and that is supposed to help. Have you tried that? I am going to try that tomorrow.
So after replacing the water pump, t stat(3 times) and fan clutch I was able to somewhat solve the problem of no heat. I do get a little heat on the low fan speeds but it gets cooler if I go to the third or fourth positions. This is ok when it's 30 or 40 outside but on days like today when the high was 4 degrees it's almost like having no heat at all. I know the heater core isn't blocked(both hoses are hot). The coolant is clean and full, I really don't think the heater core is leaking. The only things I can even think to check are maybe the actual vents or other parts under the dash. Not sure where to begin here, or if there is anything anyone can suggest but I need heat, at least more than this. I've tried running it on the max ac setting rather than defrost but it only made a small improvement. Any help is appreciated, I'm getting desperate.
Thanks!

I am having the same problem in my 98 Dodge Ram and have done EVERYTHING to repair the problem. I was informed to cover the radiator with card board and that is supposed to help. Have you tried that? I am going to try that tomorrow.


It helped me when I couldnt get the engine up to temp but is really just a temporary fix and you have to be careful not to let it overheat, not a great option in my opinion but it might get you the results you want.

I have basically the same prob, a couple weeks ago I flushed the core and it is a lot better. Sometimes even if the hoses are hot the core is still partially plugged. Flushing gets rid of the loose debris but not the white lime deposits.

And you can check the blend door by rapidly rotating to full hot and full cold, you should hear it slam where it seals.

I know it's my core and will be replacing it come spring.

Hello. Disconnect your hoses from the heater core. Hook up a spare piece of garden hose and try to blow thru it with your mouth. There should be no restriction. You must flush out the core with a garden hose from both directions several times. I usually use a hose clamp because if the core is really plugged it will blow the garden hose off. I also take a rag around the core openings after and blow air thru both directions. When it is clean you can blow thru it as easily as exhaling. I had one in a '80 bronco that only had a trickle of fluid dripping when I unhooked it because it was so clogged. That one took alot of cleaning out.

Hello. Disconnect your hoses from the heater core. Hook up a spare piece of garden hose and try to blow thru it with your mouth. There should be no restriction. You must flush out the core with a garden hose from both directions several times. I usually use a hose clamp because if the core is really plugged it will blow the garden hose off. I also take a rag around the core openings after and blow air thru both directions. When it is clean you can blow thru it as easily as exhaling. I had one in a '80 bronco that only had a trickle of fluid dripping when I unhooked it because it was so clogged. That one took alot of cleaning out.

Thanks everyone...
It's supposed to warm up to above zero tomorrow, so hopefully I can give this a try. I will keep you posted.

Thanks everyone...
It's supposed to warm up to above zero tomorrow, so hopefully I can give this a try. I will keep you posted.


Also, is there type of additive or anything you can buy that will free up any clogs in the core?

you might be able to remove the heater hoses and try to flush it with the water hose and check flow

You can use brake parts cleaner. Just spray it into the core before you flush with water. Use about half a can and let it sit 5 minutes. Usually not needed though. You can also use to final clean out after you flush with water. Be sure to blow any brake cleaner out of care until your sure its dry inside. You don't want any left in there, it wont be kind to rubber hoses or seals.

You can also use CLR, after you remove the hoses blow out as much coolant as you can by mouth. Keep both hoses up high (I used some wire and hooked them to the hood) and pour some CLR into one of them, then some water untill both hoses are full. Let it stand 10 or 15 minutes (let the hoses back down)then flush. And btw, the first flush should be a back flush, in other words , the opposite direction of normal flow. Which would be the hose on the driver side first.

Just the clear water flush has worked for me when I had a clogged heater core.

So, I haven't had a chance to do the flush due to the weather. I did check the heater hoses again and both are hot, the passenger side is too hot to grab and the driver side is pretty close to that temp. Should they be the same temp?
Also wondering what to look for to check the blend door. I looked under the dash at the blower motor area, but I'm not sure where to find the blend door or even what to look for once I find it. There is a silver canister about 3 inches tall with a vacuum line coming out of it, is this some kind of control?
Thanks again!

The book shows 2 vacuum diaphram "motors" which show as windshield/heater outlet control and windshield/panel outlet control.
The blend door control is from a small electric motor...the dash has to be removed to access it.

The book shows 2 vacuum diaphram "motors" which show as windshield/heater outlet control and windshield/panel outlet control.
The blend door control is from a small electric motor...the dash has to be removed to access it.

Thanks for the response, it looks like the trouble is my heater core. I flushed it out with clear water and now the heat works great! I'm assuming this means eventually my heater core needs to be replaced but maybe I can get by til spring...

You'll know when you need to replace it. You'll smell AF in the cab, the windsheld will get fogged when you have the drefroster on , a puddle will devolop on the passenger side floor. One or all the above can happen. I wouldn't worry about it, enjoy the heat and just keep an eye on it.

Thanks for the response, it looks like the trouble is my heater core. I flushed it out with clear water and now the heat works great!...

:biggrin: :grinyes: :rofl: :iceslolan :bananasmi :dogpile: :bigthumb: :cheers:




I'm assuming this means eventually my heater core needs to be replaced but maybe I can get by til spring...

Clogging doesn't mean there's anything wrong with the heater core...it's like a small radiator.

some of these symptoms could be a broken blend door. I found a kit that repairs the broken blend door problem with no dash removal and takes about an hour. The kit is called the HeaterTreater and they have installation videos on youtube. check it out: www.heatertreater.net