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Discussion Starter #1 (Edited)
Now that I have the electrical sorted out on the 92 3.0 its time to quite down the front of engine components.the air pump seems to be one of the culprits, noisy bearings I think? they are quite expensive to buy.question is are the bearings replaceable ?
the flex fan has a little play,maybe 1/4"
the fan bearing bracket also may be contributing.not sure yet
I do have a new Idler pulley for above air pump.the old one is def shot.
most of the noise comes from left side ,passenger side USA
when engine is Idling every thing runs smooth so I just think its bearings in the accessories
think I'll manually rev engine and watch components,see if there's any wobble.belt is new

This is the 1st pulley I'll be replacing

here's the air pump

and flex fan ,water pump


:confused:
 

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The bearings should be replaceable. Bearing, Ball Bearing, Roller Bearing at Online Bearing Store | BearingsDirect.Com seems to have everything, and once you take them out you can determine the size and order. I've not figured out how to determine the size before taking them out, to order beforehand. Then you just do the freezer / oven thing and either pound them in with a sledge or push them in with a big vice.
 

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One possible source of front-of-the-engine noise is the belt tensioner shock. The rubber bushings at each end (especially the top end) shrink, get hard, and allow play. This can make an ugly noise that is difficult to track down. TE#1 developed it and I was certain that it was belt idle pulley bearings or the fan idler bracket/bearing and replaced them. Imagine my irritation when I started her up and the same noise was there. A phone call to a trusted Benz tech set me straight and I used a pry bar to restrain the top of the shock. Noise gone! Good for me since I was thinking timing chain tensioner.
 

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A mechanic's stethoscope for $5 from Harbor Freight, used with care, should help to locate the source of the noise(s).
 

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That smog pump looks so clean its ridiculouse, the wire from the magnet for it is thick, looks newer. Just saying it looks rebuilt. The bearing is replaceable but after I did the small one that is used when it is engaged it just wore out so it may be too tight or too loose of a fit or not a perfect bearing I guess. I just unplugged it. Only is engaged at start up anyway so when warm it should not be engaged anyway. I would bet Idler puller or water pump for noise.

Good Luck.
 

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The clutch fan bracket bearing should be suspect. Mine was very noisy and made in Slovakia! As far as your air pump, I wouldn't go in there and replace the bearings. It's tricky and you need to replace everything, not just the end bearings, but the vane bearings as well. You'd be better off to buy a rebuilt one and submit yours as a core, before it goes totally out.

But agree, you should try to pinpoint the exact location. I had a nice auto stethoscope, but it was stolen with the rest of my mechanic tools. Now I use a two foot length of 1/2" copper pipe. Copper conducts sound like an amplifier...works for me. Replace any idler pulley as a matter of course-especially if they are high mileage.

Kevin
 

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+1 on replacing fan bearing bracket, especially since you already confirmed you have play in the fan clutch. Also suggest you overhaul the belt drive system, if not done already, by replacing every pulley, idler, tensioner, belt in the system. I make this standard procedure with every water pump job. They all have to work together in harmony, and old and new pieces don't seem to work well together.

You don't want that bearing to let loose at freeway speeds as it will destroy your radiator/trans cooler hoses, damage the fan and sometimes even dent the hood.

Seen it happen.
 

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Discussion Starter #12
Agreed on replacing all.but for now cost is prohibitive .Wifey getting sick of me working on my sons ebay special with needs.I did the hg job along with other things I'm probably around 1500 on parts so far,installed by your truly!
Fan has maybe 1/4" to 1/8" play not sure what the limits are.
but noise def from air pump area,the I-pulley next to it def bad.when I was rebuilding top of motor that pulley was frozen! had to loosen it with strap wrench! so it could be the main culprit. car has 119k on it ,heck my 300se with 161k is pretty quite, so for now I'll start on the pass side noise and go from there.wish I had a extra grand laying around I'd do the whole lot! prop taxs due in Dec. def blows my budget!:thumbsup:
 

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One possible source of front-of-the-engine noise is the belt tensioner shock. The rubber bushings at each end (especially the top end) shrink, get hard, and allow play. This can make an ugly noise that is difficult to track down.
+1 for this... the hard metallic rattle mine made when it's bush degraded at the top mount led me to believe something expensive was about to let go in a big way... sounds like yours is ok, but for anyone else tracing a front-of-engine death rattle, check it first for play... might be your lucky day. I managed a temporary cure with some washers to take up the slack in the mount before replacing it the next time I did the belt. Here's a pic of the new one, as you can see its very easy to check.
 

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I've allways used a really long screw driver up to ear drum,you can hear it all
Any metal will conduct sound...even solid metal. But I find copper tubing to really amplify sound well.:thumbsup: It helps to have good ears though, which I don't have anymore.:(

Kevin
 

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The timing of this topic is good as I'm having a noisy air pump issue. When I put my hand on the pump, I can feel the vibration and noise from a bad bearing. As of now, I'm not sure which bearing is bad but it's definitely coming from the air pump.
 

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+1 on replacing fan bearing bracket, especially since you already confirmed you have play in the fan clutch. Also suggest you overhaul the belt drive system, if not done already, by replacing every pulley, idler, tensioner, belt in the system. I make this standard procedure with every water pump job. They all have to work together in harmony, and old and new pieces don't seem to work well together.

You don't want that bearing to let loose at freeway speeds as it will destroy your radiator/trans cooler hoses, damage the fan and sometimes even dent the hood.

Seen it happen.
The only problem was that in my research, I wasn't able to go above Febi for a quality fan bearing bracket assembly. I think I wound up with Febi and I'm not happy about it....probably better than Slovakia though.:rolleyes:

Kevin
 

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The timing of this topic is good as I'm having a noisy air pump issue. When I put my hand on the pump, I can feel the vibration and noise from a bad bearing. As of now, I'm not sure which bearing is bad but it's definitely coming from the air pump.
I've rebuilt air pumps before with indifferent results...that's why I recommend buying a reman unit with a good warranty. If you're determined to do it yourself, replace ALL the bearing in the pump and make sure there is no drag or binding anywhere. Trust me, the people that reman these have infinitely better tools, machines & testing procedures than you have at your disposal.:D

Kevin
 
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