Hello all,98 Ram 1500 QC 4x4

Noticed last couple of weeks that I am getting an antifreeze smell through the vents when the AC is on. Looked in the engine bay at heater hoses, they were dry. Checked the carpet under the passenger side dash, all dry. I assume my heater core is leaking? Any other way to confirm? Places to look? Not coolant loss showing in the overflow tank, so small leak currently. I am in Florida so haven’t used the heat yet.

 

Heater core leaking?

 

Get a UV dye kit. This will be a pair of yellow safety glasses and a UV (black light) pen light. Get a bottle of UV dye for water based systems and add it to your radiator. Drive it for a bit and then use the glasses (I'm not kidding USE the glasses as UV can ruin your eyes.). You'll see a greenish yellow streak where the coolant is leaking. If it's coming out of the a/c drain, it's probably your heater core. However, it could just be a loose clamp or pin hole in a hose. My first guess would be a water pump starting to fail and the coolant is coming out the weep hole. This is hard to see but the spray of dye around it will show up right away.

 

Try putting it on defrost and see if the windshield fogs up, If so most likely you have a leak.

 

My heater core instantly fogged the windshield if I put it on defrost on a cold morning when it sprung a leak.
Look at your freeze plugs and around the timing cover. The timing cover is a tricky one because the coolant will dry before dripping if it's a small leak since the fan is blasting it when the engine is running.

 

I had the same smell in a 98 ram 1500 5.9 no leaks changed the heater core and it was fixed.

 

I always prefer to know exactly what is leaking before replacing parts. That's why I like to use the dye. Heater cores are rather aggravating. If it's leaking, then by all means, replace it. However, the vents at the base of the windshield draw in air from the front of the truck and if the water pump is going out and the heater core is good,you will be making two repairs, one of which is unnecessary.

 

I just checked the windshield on defrost, did not fog it up. I have the dye kit in my cart on Amazon. Will report back with what I find. Thank you all for your input and advice.
Although I think it is a bad heater core I agree with Grouch, I don’t want to change the heater core then find out it is something else.

 

The test kit has saved me many an hour over the years. Although I cannot stress enough the need for the glasses. The UV is nasty stuff.