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Weird noise from under the big metal door in the front

Yesterday, after driving to my friends house and parking i went inside, then we left (in his car), and i ended up back at my car and hour and a half later. it had been running and sounding normal when i had first arrived at my friends house. then when i get back to my car, i start it up, and i hear this noise from the engine. i wouldn't call it grinding, but more like a the sound of an air compressor, but like it came from a small air compressor (the noise is higher pitched than the typical air compressor "sound").


lately i've noticed my oil pressure not staying at where it typically used to run at. typically my oil pressure would be at 3 and then sometimes pull up to 3.5 while accelerating. then i noticed it staying around 2.5... then eventually working it's way down to where it was yesterday to 2. even dropping below 2 a little...


i drove my car home last night with this condition, and got a ride to work this morning. oil pump seems like an obvious answer... because over a couple weeks my oil pressure has been working it's way down from 3 to 2... not to mention, i don't believe 2 is not an acceptable oil pressure (correct?)


as a side note, my power steering works, and my water pump works

any ideas? scared and crying. please relieve me, but i have a feeling the truth of the matter will only be worse than i already think it is...

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Old 11-19-2003, 07:53 AM
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That compressor sound is probably the fuel pump....

The oil pressure being warm between 2-3 at idle is normal, under load it should jump up to 4-5. It really also makes a difference the weight of oil you use.
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Old 11-19-2003, 09:23 AM
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The fuel pump is located in the rear, if the sound is coming from the front I don't think it will be the fuel pump.

Does the sound change as the RPM's change?

The alternator will make a 'grinding', and/or 'whine', sound as the bearings start to go bad. The car will run, and you may not notice any change to the electrical output, but the alternator will 'whine' and change pitch/sound as the rpm's change. This will only get louder the longer you wait to have it replaced.

I don't think the oil pump will slowly loose pressure, I think it either works or it doesn't. It is a 'gear' within a 'gear' on the front of the engine, behind the crank shaft pully, and drives the oil up into the oil cooler, and on thru the rest of the system. Others may know more...

Good luck
Old 11-19-2003, 10:09 AM
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DS Did the sound go away after it started? Would "whine" be more accurate as to the sound? Sman
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Old 11-19-2003, 12:38 PM
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it is not a whine, more like a motor running. has almost the exact sound of an air compressor running. changes with engine speed.

ok, it's not the water pump, because i don't overheat when i drive. and we also ruled out the oil pump, because i have oil pressure. also not the power steering because my power steering works. can't be fuel pump because it's from under the hood.

alternator is the only thing left, isn't it?
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Old 11-19-2003, 03:45 PM
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just wondering... where is the alternator located? are alternators expensive? are there any substitutes? is an alternator replacement difficult?
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Old 11-19-2003, 04:08 PM
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The alternator is not that big of a job. It's located toward the front right (driver's side) section of the engine, close to the radiator reservoir, but underneath the upper radiator hose. You may want to take your car to Auto Zone, Pep Boys, NAPA or somewhere like that and let them test the alternator before spending the bucks unnecessarily. If your alternator is going bad, then chances are you will start having other symptoms: battery not charging fully, dim lights, etc. What part of Austin are you in?
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Old 11-19-2003, 07:51 PM
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just wondering does your car have AC? if so, thats what you might be hearing.
I have noticed a similar noise with mine (when it was running) and i took a stethascope and scoped out the entire engine bay until i come across the AC unit. it was making that air compressor sound that you are describing. smaller motor with a higher pitch than the engine itself.
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Old 11-19-2003, 08:24 PM
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it's your semitruck airhorn compressor
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Old 11-19-2003, 09:00 PM
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i live in north austin, i haven't noticed any power issues.
I have a/c, and it works. but i never run the a/c, and even when the a/c is on, it doesn't change the sound.
couldn't it be just the alternator bearings?
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Old 11-20-2003, 08:18 AM
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i found the problem. apparently when i had pulled the hood popping cable from inside the car, to get more slack, it had been rubbing against the alternator pulley. i am so relieved, words can not explain. i found this when i was putting in my new thermoswitch... yay! i'm so happy.
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Old 11-23-2003, 10:18 PM
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Quote:
Originally posted by ds475
are there any substitutes?
THERE IS NO SUBSTITUTE

Congrats in any way!
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Old 11-24-2003, 12:45 AM
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Quote:
Originally posted by Manute
THERE IS NO SUBSTITUTE
yep, manute is definitely one of a kind!!

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Old 11-25-2003, 03:34 AM
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