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  #1  
Old 07-18-2004, 07:30 PM
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Location: Northern California
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Unhappy HELP with Tapping sound!!!

My SD started making a funny knocking sound yesterday. It reminds me of loose valves a little but not quite. Also it is loud enough that I didn't want to just keep driving it. It is kind of like a double tap one louder than the other once or so a revolution.

So I pulled off the VC checked all the valves and all are good. I also thought it might be the chain stating to come apart but it looks fine also. With the cam marks lined up it reads ~3.5deg. at the crank.

However I got it to recreate the sound while manually turning it over. It is coming from the area of the vaccume pump and IP.

As I slowly rotate the motor it makes a creaking(something being conmpressed?) sound for about 20 degreees of rotation and then a light knock followed by a louder knock within another 5 degrees of rotation. It seemed to do it at least 2X per revolution.

I'm a little worried and wont drive it until I have it fixed.

Any help will be greatly appreciated!

Thanks,
Stephen

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85 300D 305K miles WVO(105K so far), Mine
82 300SD 235K miles BIO-D, Wifes
96 F250 SC PSD 4X4 285K MILES BIO-D, Ours
89 BRONCO 182K MILES sold
Finally Compression Ignition Only!

Last edited by psdsteve; 07-19-2004 at 12:34 PM.
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  #2  
Old 07-18-2004, 08:06 PM
fj bertrand's Avatar
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did you experience anything funny before the knocking noise started. you haven't given enough information
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  #3  
Old 07-18-2004, 08:17 PM
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I forgot to say that there are no other problems other than the sound. The car is running exactly the same as before the sound started.

I am thinking it is something in the vacuume pump. Is it even possible for it to make a loud tapping noise?

Thanks,
Stephen
__________________
85 300D 305K miles WVO(105K so far), Mine
82 300SD 235K miles BIO-D, Wifes
96 F250 SC PSD 4X4 285K MILES BIO-D, Ours
89 BRONCO 182K MILES sold
Finally Compression Ignition Only!

Last edited by psdsteve; 07-19-2004 at 12:36 PM.
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  #4  
Old 07-19-2004, 12:38 PM
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Join Date: Feb 2004
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Posts: 163
Also can the IP be having a problem that is causing the noise. I don't remember reading of this type of symptom on an IP failure.

Stephen
__________________
85 300D 305K miles WVO(105K so far), Mine
82 300SD 235K miles BIO-D, Wifes
96 F250 SC PSD 4X4 285K MILES BIO-D, Ours
89 BRONCO 182K MILES sold
Finally Compression Ignition Only!
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  #5  
Old 07-19-2004, 04:18 PM
Old Deis
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That vacuum pump can breakup and if you are very lucky will give you some advance notice, like noise.
Other times it starts throwing parts around. Not to common, but it does happen.
Take it off and look at it now. Could save an engine later.
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  #6  
Old 07-19-2004, 07:30 PM
Wes Bender's Avatar
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Join Date: Mar 2001
Location: Alpine, AZ / Green Valley, AZ
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Old Dies is right on. A tapping sound coming from the vacuum pump is a warning. If it fails, it will probably take out the timing chain with a resultant catastrophic failure when valves meet pistons. Check the vacuum pump before you go anywhere with it.
(Don't ask me how I know....)

Cheers,
Wes
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  #7  
Old 07-20-2004, 01:03 AM
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Posts: 163
OK, now I have a starting point!

Is there any reason to leave the valve cover off when R&R ing the Vacuume pump?

I know nothing about the process so It's off to search the archives I go. I still have vacuume but I guess that may not be indicative of pending failure?

Thanks Much,
Stephen

__________________
85 300D 305K miles WVO(105K so far), Mine
82 300SD 235K miles BIO-D, Wifes
96 F250 SC PSD 4X4 285K MILES BIO-D, Ours
89 BRONCO 182K MILES sold
Finally Compression Ignition Only!
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