Cold weather hum, transmission & heater

[Alan]

If the temperature is below 28 degrees Fahrenheit and after my 96 XLT reaches temperature, it hums like a moose. The sound comes from the passenger side of the engine compartment. The hum only occurs when the transmission is placed in drive or park with the heater on. Once I give it gas the hum goes away. The hum does not happen if the temperature is over 30 degrees, or if the heater is off. I cleaned the IAC based on other threads, but the hum still happens.

 

[dogfriend]

http://www.explorerforum.com/forums/showthread.php?t=85293&highlight=IAC

See if its the same as in the video.

 

[Alan]

Thanks for the tip. I took off the black button and tried to get the cartridges out. Unfortunately, I can't. Not wanting to damage the device, I called Ford and they said they don't sell the black button thing separately. In fact they said it’s not suppose to come off. Ford suggested replacing the entire IAC for $102. I then called AutoZone who said the same thing, but only charge $40 / $60 depending on which OEM part I want. Before I do anything I'm going to try and wash out the button with alcohol.

 

[dogfriend]

The plastic piece inside the "black button" just snaps into the outer shell. I pulled it apart by grabbing with needle nose pliers and pulling straight out. You don't have much to lose; if you break it, you can buy a new IAC which is what the dealer is trying to tell you.

BTW, if you want to get the Ford part, try FastPartsNetwork.com for better prices. The aftermarket part will probably work just as well.

I think the humming noise is because of the restriction caused by the dirty felt filters inside the "black button"

Yours does it when cold, mine does it when hot.

 

[Alan]

First, there was talk about kudos in other threads. For the record, I appreciate all the extra work and effort made to help those of us when we turn to a forum like this for help. It is appreciated. As for my current situation, I soaked the entire filter in alcohol, drained and repeated several times. After allowing it to dry, I re-installed the filter and drove the XLT. While warming it up the next morning my Check Engine (MIL) light came on. I drove it for two days without a hum (knock on wood). I then connected my OBD-II scanner to the XLT. I had P0171 STL (B1) and P0174 STL(B2) registered in Mode 03 and Mode 07 respectively. Both indicate Bank one and two were too lean. I'm hoping the added air in the IAC caused this. It seems too coincidental. I cleared the MIL and all is good (knock on wood). I’ll continue to monitor and post if things change. Thanks again.

 

[dogfriend]

If your codes return, I would first check the gasket where the IAC bolts onto the upper intake manifold. Make sure that it isn't leaking because this will cause a vacuum leak and may be the cause of the codes.

Also, check out this thread:

http://www.explorerforum.com/forums/showthread.php?t=145587&highlight=P0171

 

[Alan]

Okay, it's been over a week. We've endured frigid temperatures, snow and ice in the North East. Everything I've done with respect to cleaning the IAC and its "button" filter, clearing the codes have worked. Just writing to bring closer in case someone references to this thread in the future. I'll continue to keep my fingers crossed, and knock on wood. Thanks to all who suggested workable solutions.