HVAC Musty Smell / Odor

[MidLifeManifustang]

Any update?

Yeah. The new filter helped a bit but didn’t fix the problem.

I don’t see an obvious way to inject foam from below so I’ll have to try spraying various things into the intake with the filter removed as the system is running. If that doesn’t work. I guess it’s over to the dealer.

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[Zig]

Yeah. The new filter helped a bit but didn’t fix the problem.

I don’t see an obvious way to inject foam from below so I’ll have to try spraying various things into the intake with the filter removed as the system is running. If that doesn’t work. I guess it’s over to the dealer.

I’d be tempted to mist the carpet with some vinegar, and then close it up and let her idle for 10-20 minutes (vented seats on high if you have them) on recirc fan before spraying the intake from the outside.

 

[MidLifeManifustang]

I splurged for 72-hour access to the Ford Service manual and here's a summary of the official procedure for odor treatment (Note: many warnings about not spilling water or chemicals on floor or electronics removed for legibility)

Identify the source of the odor.

• Check the evaporator core drain tube for restriction.
• Check the passenger and driver side carpet for moisture. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
• Check the cabin air filter and cabin air filter cover for moisture resulting from water bypassing the cowl baffling system. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
• Check the inner cowl drain area and air inlet screen for material obstruction or standing water. Inspect the area removing any standing water and cleaning the air inlet screen if possible, by using a wet/dry vacuum.

1. Open all vehicle windows and doors.
2. Make sure the A/C is off.
3. Remove the cabin air filter.
4. Remove the blower motor speed control.
5. Add water (Distilled or deionized water is preferred. Do not apply tap water) in applicator bottle and apply with the A/C Odor Remover Flexible Applicator Tool (This is service tool 258-62644 a.k.a. Ulti-Flex Pressure Spray Tool. which hooks up to a compressor and has a long, flexible nozzle to fit into tricky places )
6. Insert the nozzle into the evaporator housing and direct the spray toward the evaporator core face. Spray the deionized water to entire evaporator for 5 - 10 minutes.
7. Install the blower motor speed control.
8. Select REGISTER/PANEL mode (A/C off).
9. Adjust the temperature setting to full warm.
10. Adjust the blower motor speed to HI.
11. Run the engine for 25 minutes to dry out the A/C system.
12. Turn the ignition OFF.
13. Add one full bottle of Motorcraft A/C Cooling Coil Coating (YN-29) to the A/C Odor Remover Flexible Applicator tool.
14. Remove the blower motor speed control.
15. Insert the nozzle into the evaporator housing and direct the spray toward the evaporator core face. Spray the entire evaporator core face until empty.
16. Install the blower motor speed control.
17. Repeat Steps 9 through 13 to cure the cooling coil coating.
18. Install a new cabin air filter

From what I can tell, you need to spray the evaporator core with the special nozzle/tool via a hole left either by the removal of the blower motor speed control or of the cabin air filter. Unclear unless I get under there myself.

That said, this seems somewhat involved and I don't have the tool or anything like it to do this job so I'm leaning towards having a dealer do this (unless someone else here has done this and can tell me it's no big deal...)

 

[Zig]

I splurged for 72-hour access to the Ford Service manual and here's a summary of the official procedure for odor treatment (Note: many warnings about not spilling water or chemicals on floor or electronics removed for legibility)

Identify the source of the odor.

• Check the evaporator core drain tube for restriction.
• Check the passenger and driver side carpet for moisture. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
• Check the cabin air filter and cabin air filter cover for moisture resulting from water bypassing the cowl baffling system. If moisture is found, A/C odor treatment is not necessary. Diagnose for a water leak as needed.
• Check the inner cowl drain area and air inlet screen for material obstruction or standing water. Inspect the area removing any standing water and cleaning the air inlet screen if possible, by using a wet/dry vacuum.

1. Open all vehicle windows and doors.
2. Make sure the A/C is off.
3. Remove the cabin air filter.
4. Remove the blower motor speed control.
5. Add water (Distilled or deionized water is preferred. Do not apply tap water) in applicator bottle and apply with the A/C Odor Remover Flexible Applicator Tool (This is service tool 258-62644 a.k.a. Ulti-Flex Pressure Spray Tool. which hooks up to a compressor and has a long, flexible nozzle to fit into tricky places )
6. Insert the nozzle into the evaporator housing and direct the spray toward the evaporator core face. Spray the deionized water to entire evaporator for 5 - 10 minutes.
7. Install the blower motor speed control.
8. Select REGISTER/PANEL mode (A/C off).
9. Adjust the temperature setting to full warm.
10. Adjust the blower motor speed to HI.
11. Run the engine for 25 minutes to dry out the A/C system.
12. Turn the ignition OFF.
13. Add one full bottle of Motorcraft A/C Cooling Coil Coating (YN-29) to the A/C Odor Remover Flexible Applicator tool.
14. Remove the blower motor speed control.
15. Insert the nozzle into the evaporator housing and direct the spray toward the evaporator core face. Spray the entire evaporator core face until empty.
16. Install the blower motor speed control.
17. Repeat Steps 9 through 13 to cure the cooling coil coating.
18. Install a new cabin air filter

From what I can tell, you need to spray the evaporator core with the special nozzle/tool via a hole left either by the removal of the blower motor speed control or of the cabin air filter. Unclear unless I get under there myself.

That said, this seems somewhat involved and I don't have the tool or anything like it to do this job so I'm leaning towards having a dealer do this (unless someone else here has done this and can tell me it's no big deal...)

to cure the cooling coil coating.

That smells like a warranty job, but now that you know do you really wanna?

 

[Angdeviis]

I’d start by pulling the cabin filter to check for trapped moisture and then hit the evaporator box with an evaporator cleaner foam through the intake by the cowl; that made a big difference on mine. I also asked the dealer to confirm the drain line wasn’t kinked. For the leftover funk in the cabin, I burned some smoke odor exterminator candle scents at home and it cleared the smell from my vents pretty well after the cleaning.

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