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Hey guys I just got my 1998 s500 and am thrilled to be in the MB family. However, I couldnt help but notice like a supercharger like sound coming from the engine bay. It is like an airy undertone to the engine and it increases in pitch as the engine rpms increase. Could this be transmission problem's or pulleys or something else. Help will be much appreciated.
 

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Hey guys I just got my 1998 s500 and am thrilled to be in the MB family. However, I couldnt help but notice like a supercharger like sound coming from the engine bay. It is like an airy undertone to the engine and it increases in pitch as the engine rpms increase. Could this be transmission problem's or pulleys or something else. Help will be much appreciated.
The engine, and all the components connected to the engine via the fan belt
(water pump, AC-clutch, fan belt pully, alternator, power steering pump, etc) could
be suspect. Or just the belt itself. I think that you will not get any qualified answer on this, unless you
open the hood, and try to pinpoint better where the sound come from.

You could use a hose to your ear, and move that around to locate the sound.

It could also be further back, like converter, where you cannot reach it from the engine
bay, but then you at least have eliminated the front side.

Good luck,
syljua
 

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I had a whining noise. I minimized it by changing the belt tensioner pulley (easy and inexpensive) and eliminated it by taking out the alternator and getting it rebuilt (more work and more expense that changing the belt tensioner pulley). I did use a stethoscope to pinpoint the source, though, but it was both difficult and dangerous to place the stethoscope on the alternator....
 

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whinning noise

Hey guys I just got my 1998 s500 and am thrilled to be in the MB family. However, I couldnt help but notice like a supercharger like sound coming from the engine bay. It is like an airy undertone to the engine and it increases in pitch as the engine rpms increase. Could this be transmission problem's or pulleys or something else. Help will be much appreciated.[/


Power steering noise
When the fluid is low and you add some, it may still need more after you run it for awhile. The reason is that as the pump pumps the fluid through the lines, this also normally pushes any air out the lines. Keep filling and checking after you start the car and turn the wheel from side to side all the way.

The bigger question is why do you need to add fluid? After you locate and fix that leak, you can address the whine. If it is a Ford, it may be somewhat normal. Like Drazi said, "It may be air trapped in the line." Or the pump may be damaged from running it dry, or there is bilge in the line, starving the pump. Let's assume you have kept up on the maintenance and have flushed the fluid when it was dirty. Let's also assume that the pump is not damaged and you have found and fixed any leaks. Try this: pull the fluid out of the reservior and add one bottle of Lucas brand power steering additive, and top with power steering fluid. I have found this stuff pretty good at resolving many power steering problems. I'm not a big supporter of "Snake Oil", but have had good luck with it.

If it's a Ford, it's because they use plastic parts in their casings, though most other car companies do the same. If that's not the case, then your pump is receiving too much stress from turning. Try lubing up the chassis and changing the fluid completely. It wouldn't hurt to check your lines either. Sometimes blockage can cause too much stress on the pump too.

First thing is why are you adding fluid. If it has a leak, then I would address that problem first. A pump will not bleed air out of the system if it is leaking. If everything seems to be okay and your pump still whines, then replace the pump, preferably with a new one from the dealer. The so-called rebuilt pumps that you can buy from places like Autozone, O'Reilly, etc. are cheaply rebuilt, especially if it's a Ford. They don't bleed out air properly, resulting in improper pump pressures. A good pump will bleed out almost immediately, with the turn of the wheel a few times. If it doesn't, then your pump will more than likely never completely bleed out. Buy a new pump from the dealer--it costs more, but if you're like me and don't like the noise, then it's worth it.

You probably have air trapped in the power steering fluid system. Bleed the air out by revving the engine to about 1500-2000 rpms and turning the steering wheel almost all the way from one side to the other a few times. This should bleed out the air and take care of your problem.

If the noise is similar to that of a dry bearing, then the problem is probably the power steering pump itself. If the noise you hear has a "click, click, click" to it when you make turns in your vehicle, then the problem is more-than-likely your CV joints. If the noise is screeching, check your belt for wear-and-tear and proper tension (see owner's manual), and the pulleys that the belt turns, including the air conditioning compressor motor and its clutch/pulley.


Read more: Why would the power steering make noise even after fluid has been added
 

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tackleberry, what is a smog pump, I didnt even know I had that? what does it do?
Air injection into the exhaust to more quickly get the cat to work.

Now, is you noise gradually disappearing? Remember, any part thats connected
via the fan belt, which is hard to turn when cold, will cause the belt to whine
until it moves more freely...

br,
syljua
 

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syljua, On my car I have taken out my cats. Does this make a difference? There is only a whining noise on the first startup of the day it lasts untill the car warms up and it dissapears (arround 3-5 min). On every other startup during the day everything is normal.
 
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