Hey all,

I have been putting off a coolant smell when I turn on my heater. Im figuring its my heater core, but havent thought much of it and carpet isnt wet. Unless the carpet normally gets wet under that black piece (I think its the backing to the insulation to the floor).... Anyways, I checked my coolant for ****s and giggles....it has always been right on the hot mark when its hot and cold when its cold. There is no coolant in the reservoir now.

My question is (unless the coolant has soaked into the insulation of the floor board, where could it be going? I dont have puddles under my truck, nothing leaks on my truck and its not burning coolant (no sweet smell in exhaust and no white smoke).

Also, if I pull my dash for the heater core...is it the whole dash or just the lower part like other vehicles? The reason I ask is my dash is cracked and I could give a **** less to replace it since Im in NM where its hot and sunny all the time. Does the dash have a frame, so when I take it out, the dash wont just crumble?

Thanks guys

 

Coolant leaks can be 'funny'. (and I don't mean "ha-ha" funny..... ) Mine was losing coolant at an alarming rate, yet, I NEVER found evidence of a leak. Eventually, the leak got bad enough, that I could actually see it dripping.... was coming right out of the drivers side engine mount. (there is a freeze plug behind it, they like to rust out.) At first, it will only leak when the system is under pressure, and even then, if the pump isn't stirring it up, you won't see it..... until it gets bad enough.

My next leak was between the timing cover, and the block, on the drivers side. It was slow at first, basically unnoticeable. Until it decided let loose one day, and REALLY start leaking. It was hard to determine where it was actually coming from, as it would run down the front of the block, wick along the oil pan gasket surface, and then drip off at the BACK of the motor...... That was fun to find.

There is also the little heater bypass hose under the bracket for the alternator, and a/c compressor. You can't see it, you can't touch it, and when it leaks, it sits on top of the timing cover.... so, you can't really TELL where it's actually coming from.

Thermostat housing is another nice spot. The neck corrodes quite nicely, and eventually, it starts running down onto the same spot as the bypass hose..... Heater hose on the passenger side is the same way.

The return tube is another possible culprit. Just has an o-ring in there to seal it. It's kinda a tight fit, so, it is rather easy to marf up the o-ring, and end up with a leak. (yes, I know this because I did it...... ooops.) The return tube also likes to corrode, and the part below the o-ring falls off..... so, o-ring feels free to displace itself, and you end up with a leak. (yep, done that one too....) Parts stores carry a new tube, with o-ring, for like ten bucks. (if that proves to be a problem.)

Freeze plugs on the back of the block like to corrode and leak too. Gotta drop the trans to change those. As I don't wanna do that in my driveway, in the sub-freezing temps, a bottle of bars-leaks went in. That has it under control for now. When the weather again gets warmer, I will fix it right. (gonna order up a set of brass freeze plugs, and replace them ALL, including the one I have already changed.)

 

do you only smell it inside of the cab, or also on the outside. if inside only, then its going to be the heater.

the leak is probably so teeny tiny small that its just seeping and evaporating. fill it all back up and monitor it daily to identify the rate of the leak.

if the leak gets bad and you can't attend to it at that moment, then bypass the heater core.

sorry, no personal experience on the dash or heater core, but look in the faq's at the top. i think there are some pics, and as i recall, the dash is detached and leaned back towards the seat, pretty much the same as if you are removing and replacing it. i don't think there is a framework, so the sob is going to disintegrate.

 

here you go.
https://dodgeforum.com/forum/2nd-gen...ater-core.html

 

The OP has the exact same problem I do. What would be the problem if you could smell it on the outside as I can smell it inside and out but have no visible leaks.

 

if the windshield is all fogged up, then its obviously the heater core leaking inside.

if the smell is inside only, then its likely the heater core.

if the smell is outside and inside, but no window fog, and no wet carpet, and no drips, then i'd look on the outside, checking freeze plugs, heater hoses, ac condensation drain tube, water pump - especially the tell-tale drip at the bottom. the smell from an outside leak can be drawn in through the fresh air vent.

 

I have only noticed it on the inside. I called a mechanic buddy who knows quite a bit more than I do about vehicles, and he said that on Dodge's when you put the heat on (anything but defrost) it pulls outside air in from the engine compartment and defrost does not pull from engine compartment. He said if I only smell it on defrost that its the heater core, but if I smell it on other than defrost, it could be a leak somewhere in the engine bay.

He also said he has had really good luck with a product called "thermagasket" which would fix both the head gasket and heater core. I looked it up and its more legit than the stuff you get off the shelf.

Otherwise, I might have heater core AND head gasket problems....

I will do some more checkin on the truck.

Thanks guys

 

i didn't read anything in your post that indicated a head gasket problem. that would be associated with overheating, water in oil (chocolate milk), serious white smoke, coolant smell in exhaust, low compression, and/or running poorly.

i'm not sure if your buddy is right or not about defrost, but i do know this. if you turn your ac control to MAX AC (and the heat to the hot setting), you can hear the recirc door slam shut, and it recirculates cabin air and shuts off the fresh air. that should eliminate engine compartment odors.

 

I thought head gasket problems as well but there isn't any coolant in my oil.

 

If its heater core, Im just going to bypass the heater core I think... It doesnt get terribly cold here in New Mexico and I can always replace it later on if I want to....

I am going to try and rent a coolant pressure tester here soon