In my 1999 Ram 1500 V8 my heater core must be going out because there is water that constantly runs under the carpet on the passenger side and I can hear gurgling sometimes and smell antifreeze. One day a few weeks ago my engine ran hot and I checked coolant, it was so dry I had to add about 2 gallons! No real problems since except the moisture continues on the passenger footwell. I made sure the drain line was cleared out, if that was the problem, it wasn't the only problem.
Another thing happening is when the A/C is on, it runs very well except sometimes it will blow warm air, then if I let off the gas some, I can hear a mixer valve or something close forcefully and then the cold air starts again right away.
The real question is if I pull the dash out to replace the core as I've read about here recently, what else should I be looking for that could be causing the clunk and then cold air? Thanks! -JerryC

 

A/C takes A LOT of engine power to run. So designers got smart and made them shut off temporarily when your motor is under load. So the momentary warm air is normal. I dont know why it would be clunking though, other then that its a 12 year old truck thats probably been well used...

 

That's a good point. I had a good bit of battery corrosion and replaced the battery, but on another car I own, that corrosion caused problems with the battery cable so I had to replace the cable. I have noticed sometimes in the past couple of weeks that the time/station display on the radio dims rather quickly and then recovers, so all of that points to a possible power supply bottleneck. I'll try to resolve that first and see if the problem stays around so when I do go to replace the core, I don't spend hours looking for a problem that I can't find. Thanks! -JerryC

 

It could be wacky vents or wild vents, just search that on google, but that switches it to defrost so idk

 

The heater core needs replace. But if you read this thread, this is most likely the problem you are having with the AC. https://dodgeforum.com/forum/2nd-gen...ild-vents.html


And wow, 2 gallons you added? Was it not overheating?

 

Zman, Yes, temp gauge had gone all the way up, so I stopped to check the fluids and noticed the coolant level. Added the 2 gallons and now it only loses coolant slowly so I don't know how it went down so fast that one time. Thanks for the link, I am going to read it now. -JerryC

 

Are you sure you didn't leave your windows down? Or it could be a prank. Or so I've been told on my heater coil question of the day

 

I doubt someone drained 2 gallons of coolant out of his truck. And it's a Heater Core, not "Coil".

 

I've added as much coolant over time. And I always got coil and core mixed up

 

Well, get with the program there bud. LOL