Heater Core Smell

I have a 2001 XJ, AW4, I6 with Aircon and there is a smell coming out of the heater box when the engine gets up to running temperature. The heater blower doesn't have to be on to get the smell, but if the heater is on then the smell is generally worse. I took it to the stealership because I was concerned that maybe the heater core was leaking. Well the Technician said he could smell the odor that I was referring to but in his opinion it wasn't antifreeze. The Technician actually thought the smell was like rubbing alcohol but I felt it didn't smell anything like rubbing alcohol. The smell is unusual and I can't really describe what it smells like. It doesn't smell like mold or mildew.
Over the summer the engine seemed to be running about 215 whereas previous summers it seemed to settle around 210, not sure if this is related or not. Over the summer I did notice the level of antifreeze was about an inch below maximum on the reservoir bottle so I filled it to maximum but it had no effect on overall coolant temperature. Any way the technician suggested putting a cleaner through the heater core. As anyone done this before or have a write up for the detergent cleaner procedure. Any comments on this problem would be gladly appreciated.

Is it a slightly oily burnt electric motor smell? It could be the blower motor itself. Does it ever get chirpy at low speeds?

I haven't heard any change in the motor noise /revs but the smell could be a burning smell, though it doesn't smell like an electrical burning smell.

late model XJ's are known for leaky evaporators--

have someone verify the operating pressures for the A.C.- evaporator core leaks are common and the smell of refrigerant/oil is unlike anything else.

OK I will get the AC checked out.
Has anybody heard of this cleaning procedure for the heater box that the Jeep technician was going to do ?

Tryfan said:

OK I will get the AC checked out.
Has anybody heard of this cleaning procedure for the heater box that the Jeep technician was going to do ?

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you can dump some CLR in there, or i did a prestone radiator flush (also flushes the heater core), the 3-6 hour stuff

How is any cleaner going to help with the smell if the heater core is not leaking? Doesn't make any sense.

x2 on the evap core; can definitely smell odd.

Could also be the rubber foam around the core itself is starting to deteriorate and melt a little, since you mentioned it was running a little warmer.

It's probably the motor itself shitting the bed; they smell wicked funky when they do.

bdahlg said:

wicked

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LOL. i knew you were from mass without even looking. my sister says wicked all the time, she lives in mass obvi.

I think the Jeep Technician was going to add a cleaner that would help clean inside the heater box and through the ducts not the heater core itself

Might be MOPAR Authentic Service and Parts antibacterial airbox cleaner and disinfectant - available ONLY from the dealer at $179.95.

aka: can of Lysol sprayed through the vents.

Thanks for the info