Well- more than the usual ones I hear on my 20+ year old vehicle. Around the end of a 500 mile trip, i started hearing this odd whining sound- I would dare say it almost sounds similar to the whine of a S/C. The sound appears to be coming from the passenger side and kind of low. I am suspecting the air injector (smog) pump. I took the serpentine belt and spun the pulleys by hand of the accessories I have on that side- the alternator too. None really have any resistance nor did the pulleys feel 'loose'. I felt the hose coming from the smog pump and it felt like there were pulses coming from it (from what I researched this is normal). I would have also suspected the belt tensioner, but the sound appeared to be originating lower in the engine bay. Has anyone heard this sound before or have any idea what would cause such a sound? It's loud enough to even drown out the whir whine of the power steering pump.
Oh yah, just in case anyone's wondering- its an LX 5.0 w/AOD, also has A/C

 

^^^ And I was gonna say, "It's a Fox, various noises are normal." Does this sound occur when the engine is on or only when the vehicle is in motion? I'd say get a mechanic's stethoscope or a long screwdriver and try to listen to each accessory as the engine is running. Would be nice if you had shorter belts and try to bypass some of the accessories, but that would be kind of unrealistic. Any play on the water pump pulley? Though the smog pump could very well be the culprit, maybe the belt tensioner could be a problem. The one in my car is worn - not the pulley or the bearing, but the part the bearing rides on looks slightly tapered/worn and it makes noises now and then. Tried swapping pulleys before realizing the bearing wasn't the problem. Good luck finding and fixing the source of the noise.

 

Well, the noises got worse this morning- pretty much sounded like the bearing in the air pump was about to fail. Luckily i had already received the new pump I ordered online... less than an hour later, noise is gone, runs smooth... well as much as can be had in a 20+ year old stock mustang There is still a leak where the air tube connects to the y tube that go to the cats, and trying to remedy that. I would just like to replace the whole 4 cat h-pipe with another stocker. And what do I do to reward my steadfast work? I go to the nearest Ford dealership and test drove the new 5.0

 

Good to hear! (Or not hear) What kind of tube can you use to connect the smog pump to the H-pipe section? Does it have to be welded or is there a hi-temp rubber or plastic one for that kind of application?

 

it looks like one tube is supposed to insert into the other one, but it seems a little split (it's a lil tough to see under there). I did feel some rubbery type residue around the tubes. I repaired it this afternoon and so far my fix appears to be working- no leaks, but we'll see how the stress of the DC area traffic will test it.

 

Be careful with the air pump.

I had one lock up on an '83 GT and it burned the belt off.

 

Oh, no worries- its already replaced with a brand new unit. My biggest fear was that it would have locked up, so I just bought a bypass serpentine belt size as insurance til my pump arrived. Since I never used the belt, i went ahead and got my money back Either way, I am sure that deer I hit was to blame.

 

Yup. Punting a 150 lb animal can do some strange things to a car.