[mjschu]

I have a 1993 Grand Marquis that has developed a strange intermittant sound that I can only describe as sounding like a fog horn. It seems to be more pronounced between 35-45 MPH when accelerating or de-accelerating. You can even feel a slight metallic vibration through the gas pedal when the sound occurs. Other than the sound, I have no driveability problems. I'm thinking it's in the trans, but when I am outside with the hood up it sounds more like it coming from the front of the car. Any ideas? I'm not reading any service codes. I did recently have the torque converter replaced under extended warranty but this sound developed some months later. One person thought a special lubricant wasn't added to the trans fluid to reduce the noise. Another thought it might be failure of the water pump or fuel pump but the car drives fine for now at least.

 

[Sweens]

Have no fear friend! It's no where near as serious as you are thinking. It's a part that Ford MotorCompany actually calls a hoot tube! Believe it or not. It's part of the emissions system -- and I believe may be connected to your EGR valve - go to the dealer - tell em you need a hoot tube - they wont even look at you funny. It's an easy replacement - maybe 15 minutes!

 

[mjschu]

Thanks much for your response! Strange you should say that the hoot tube is connected to the EGR valve because I just had that replaced and that included a small flexible tube on the side which had rusted through and a copper tube. However, this sound did not start right after that but within a few weeks later. I'm not doubting what you're saying but I wonder what's happened? The mechanic showed me the old EGR valve which I had marked so I know they replaced it. Could they have failed to connect it properly or could something have worked loose? (I have a 4.6 engine where the EGR valve is sandwiched behind the engine and the firewall making it pretty inaccessible. On the larger engine, I believe it's sitting nicely right near the top of the engine for easy access.)

 

[Jonathan]

I am actually having the same problem. It is a wierd sound... i notice it when at a constant speed right after an initial acceleration when I start the car cold. Like after I pull out of work onto a 40 mph road. then I tap the gas and it goes away... it is wierd... andyways, going to have to check the hoot tube then!

Jonathan

 

[mjschu]

I don't know about this hoot pipe thing. One mechanic told me it was in the evr intake system and the other in the egr exhaust system. Your symptoms are the same as mine. Can anyone else confirm what's happening? Doesn't seem to be a serious problem because it doesn't effect driveability. Actually, maybe it's a latent safety sytem activating? The strange sound does make other drivers and pedestrians avoid my car! My wife thinks its a "hoot" anyway, it let's her know when I'm pulling in the driveway coming home from work for dinner!

 

[Guest]

The Noise you hear is coming from Idle air bypass tube. Ford has a TSB on this. THe hose for the 92 and up is updated by a 96 part. The hose runs from the air cleaner inlet just before the throttle body and down tho the idle air bypass valve. it is fun to replace and i suggest the engine be very cold when you do it. I have installed a lot of these at our shop. the noise is very annoying,Alan