I've had a heater core leak before (different vehicle) so I'm familiar with the signs.

 The heater core in my '01 3500 has me questioning it. When I turn on the heater I will slowly get a fog on the inside of the windshield, then eventually on the door glass but I do not smell coolant. If I crack the windows and turn off the heater the fog will go away after a few minutes and leave no slimy film like coolant would. 

 I don't have any leaks on the floor either. I don't want to do a heater core right now. I would rather accumulate what I need to do the heater core, a/c coil and replace dash board top all at once. Probably about a $500 ordeal. I also don't like to use alumiseal or other cooling system sealers unless absolutely nessesary.

 I should also mention that the heater does blow hot air. 

 Any advise here? Is it for sure my core? Should I try a sealant for a temporary fix for now?

Edited May 11, 20204 yr by Doubletrouble

it sure sounds like a heater core.   (are you losing coolant?)

You could try bypassing the heater core and see if you still have the same symptoms.

You could also try a cold pressure test.  "rent" the tool from one of the box stores.  I love  mine..  makes troubleshooting much easier.

I know it can still be cold your way....  but you could bypass it for awhile for summer.

 

GL  HTH

Hag

Forgot to mention that also,  not loosing any coolant and the heater does blow hot air. 

What is your humidity like at the moment. (and cold/hot the ambient temp and heater temp)  It could be as simple as how you are passing  through the dew point.

When mine went, I did not get the coolant smell much, but I did have the residue. 

I would watch and wait.

 

Hag

 Humidity has been up a bit with rain here lately but the temps have been below normal. The trucks a/c needs charged at the moment to, so defrost mode doesn't pull the moisture from the cab as it should. 

Does sound like the heater core. When started I did not get any fog on the glass but would little whiffs of coolant. It is leaking the coolant would run outof the HVAC box thru the drain in the fire wall. It shouldn't touch the floor of the truck unless the case is cracked.

The only reason why a heater core will leak is the coolant has not be changed and flushed regular intervals. I will suggest to open up the full HVAC case and clean out everything. Best way to do the job and lube all the pivot points on doors and make sure the blend door coupler is broken. 

 That will be the plan, like I stated, I would like to do the a/c coil and dash all at once so it'll be a bit before I can get it done. In the mean time what is the thoughts on a sealer until I get all parts I need? Also, once I do the heater core, a/c and dash I will then flush the cooling system and remove the radiator for cleaning. (Covered in the oily mess of the breather)

 

don't do a sealer....

If the leak gets bad enough take the heater out of the coolant circuit.   Just take the hose going TO the heater, and connect it directly to the hose going FROM the heater.  This will bypass the heater core.

There are times ane places for sealers....  (Miracles in a Can)  but avoid it if you can....  that goo goes EVERYWHERE in the system, it doesn't just target your leak...

 

HTH

Hag

Another way is to cut the vacuum breaker seal on the radiator cap. This will prevent the system from building pressure. It will work for getting around and keeping the coolant in the truck. Do not tow and work the truck hard till this is fixed. 

1 hour ago, Haggar said:

don't do a sealer....

 

I agree.  My heater core started leaking in in 2008 at 136,000 miles.  I didn't replace it until 2017 at 283,000 miles.  I added a stop leak product  twice early on - something that I tell other people not to do.  Sometimes I'm not very bright.  During the years the heater core was leaking, the fogging windows continued to be a problem and slowly became worse.  I hardly ever added coolant to the system.

 

A heater core doesn't have to leak very much coolant to interfere with keeping windows clear.  Most of the time I didn't notice any coolant odor.  Once I added the stop leak product, the coolant was always cloudy and you could see particulates in the coolant.  It didn't matter how many times I changed the coolant, it wouldn't clean up.  After I replaced the heater core, I finally installed a coolant filter in parallel with the heater core circuit.  Over a three week period the coolant became crystal clear.  I left the coolant filter in the circuit and periodically replace the filter.

 

- John

 

 

 I won't put any sealer in and just keep an eye on it for now. 

I did the stop leak in the 1996 Dodge because of emergency required use of said truck needless to say it quite the mess to clean that junk out the cooling system. Sticky, gunk, that just don't rinse out. I highly suggest not using any stop leak products. 

@Mopar1973Man what sealer did you use. I have used alumi-seal I'm the past with decent results. Mainly for vehicles I was selling so I didn't see the long term effects if any. It's mainly an aluminum powder of sorts that plugs the leaks I guess.

 Just curious of what sticky gunk you refer to.

Ran a demolition derby car more than 35 years ago and after first heat had a radiator leak. We used some Copenhagen chew because that’s all we had and got satisfactory results however don’t know how it worked long term. 

Course ground black pepper good for over a year in a Toyota on Guam.

My heater hadn't been putting out adequate heat for a couple years now. Been meaning to change it, but recently I had my windows fogging up and wasn't sure what the deal was. This last time my wife and I were driving home and I got a wife of coolant, and knew I had an issue. Had a small puddle of coolant in there when I pulled it out, but wasn't loosing a lot of coolant. Just did this on Monday.

On 5/11/2020 at 10:14 AM, Tractorman said:

Over a three week period the coolant became crystal clear.  I left the coolant filter in the circuit and periodically replace the filter.

Can you share what filter you used.

Random story here...

My step-dad's van 2001 town and country just started leaking coolant on the ground, though it was head gasket or intake gasket,  once I got under it i could see it was timing cover gasket where water pump is, between block and cover. No way in hell I'm fixing that on something that is on last leg. It only has 240k on it but everything is falling off now. I put bar's leak tablets in (3) and 20 min of driving no more leak. Stuff really works and not hard to flush out. 

 I had to use the heat today, been rainy and a little cool here lately and had to make a morning trip. Anyway, turned on the heat/defrost and found this after about 20 minutes of driving.

 100% sure it's the heater core now so I guess I have some work ahead of me.

 

 I think I'll bypass it for now and begin collecting all the parts. I want to replace the heater core, a/c coil and do a good cleaning and replace the dash as well.

 So far everything seems to work as far as blend doors and such so is there anything else in there I should consider while I have it all apart? 

Heater Treater for heat/AC  blend door.  I installed one in @JAG1 truck two weeks ago in conjunction with the heater core and AC evaporator replacement. 

Note:  when installing a heater treater, before removing the dash and HVAC housing, turn the ignition key to on and set the heater controller knob to the middle position.  This will make putting the case back together easier and the motor will be indexed.

 

http://heatertreater.net/dodge-ram-95-02 

10 minutes ago, IBMobile said:

Heater Treater for heat/AC  blend door.  I installed one in @JAG1 truck two weeks ago in conjunction with the heater core and AC evaporator replacement. 

Note:  when installing a heater treater, before removing the dash and HVAC housing, turn the ignition key to on and set the heater controller knob to the middle position.  This will make putting the case back together easier and the motor will be indexed.

 

http://heatertreater.net/dodge-ram-95-02 

When l did mine the part came with a 9v battery and instructions on how to index it. Been trying figure out how to do that now since either the motor is gone or the blend stuck in AC position. I believe it is stuck in the full AC position but not sure.