I just bought an '03 Tundra AC (used). Sometimes when I shut the engine off, I hear a weird humming sound coming from the engine. It gets gradually weaker until it dies off around 10 -15 seconds. Sounds almost like a decompression. Only notice it when the Air Cond. is on. Is this the AC decompressing?
My '03 does the same if I have my a/c on medium then shut the vehicle off. I feel it is the air conditioning compressor decompressing, but I'm not 100% sure. I know it has something to do with the a/c though. Hopefully some more experienced TSer's can chime in. I wouldn't worry too much about the noise.
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-Austin
2003 Toyota Tundra SR5 TRD Sport
Thanks for the quick reply. Glad mine is not the only one. With it being used (and new to me), I'm listening out for every little tick while it is still under warrenty.
It's the refrigerant pressure equalizing through its metering valve (this device separates the high and low pressure parts of the system). If the compressor is making the noise you have big troubles and I'll bet that's not the case.
Larry
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2004 Tundra V8 Limited Access Cab 4X4, Michelin 265/65/R17 LTX-AT2's, Auto Dim Comp/Temp Mirror, Aero Turbine #2525 muffler, Access Roll Up Cover, Optima D31A battery, Multi-Vex adaptive outside mirrors, Eclipse AVN5510 Nav unit and Sirius SIR-ECL1 tuner, as of 10/07 pictures in my photo gallery
If a combo of all these whizz bangs met their claims you'd have to siphon gas out of your tank every second day and sell the excess horsepower on the third????
If your engine doesn't consume ANY oil it will seize???
Some people should not be allowed access to tools without books!!!
I've always made it a habit to shut off the a/c a few blocks before arriving at my destination, that would eliminate the hissing sound you're talking about. It might be my imagination, but I've always found that any vehicle was easier to start with the a/c off.
Humming on Engine Shut off
Linear Mode
