Help diagnosing noise - 81
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Joined: Nov 2005
Posts: 88
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From: Azusa California
Help diagnosing noise - 81
Hi,
My '81 has developed some noise in the engine compartment (right side). It's kind of a clacking that I start to hear around maybe 1800 RPM and gets louder around 2000. But only when driving; I can rev it to the same levels in park without hearing it.
I have a couple of opinions : the mechanic thought it might an exhaust leak; and my neighbor (sort of an old school shade tree mechanic!) thought it was a lifter.
I put some Rislone in it hoping it was a stuck lifter, but that was just yesterday, no change yet of course. But if it was a lifter, wouldn't I hear it in park?
So, I'll leave it at that and ask for your diagnostic opinions - I'm not a mechanic, but I would like some opinions before I take it back in (mechanic wants more time to look at it- he wasn't really sure what's going on)
Thanks in advance,
Steve
My '81 has developed some noise in the engine compartment (right side). It's kind of a clacking that I start to hear around maybe 1800 RPM and gets louder around 2000. But only when driving; I can rev it to the same levels in park without hearing it.
I have a couple of opinions : the mechanic thought it might an exhaust leak; and my neighbor (sort of an old school shade tree mechanic!) thought it was a lifter.
I put some Rislone in it hoping it was a stuck lifter, but that was just yesterday, no change yet of course. But if it was a lifter, wouldn't I hear it in park?
So, I'll leave it at that and ask for your diagnostic opinions - I'm not a mechanic, but I would like some opinions before I take it back in (mechanic wants more time to look at it- he wasn't really sure what's going on)
Thanks in advance,
Steve
Race Director
Joined: Jul 2004
Posts: 12,676
Likes: 329
From: Scottsdale Arizona
Try looking at your fan blades and shroud. I'm willing to bet that you'll find a shiney spot on them where they meet.
The clue is that it's different in gear vs in park at the same rpm.
Hope this does it for you.
The clue is that it's different in gear vs in park at the same rpm.
Hope this does it for you.
Last edited by CA-Legal-Vette; Jun 10, 2006 at 10:45 AM.
Thread Starter
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Joined: Nov 2005
Posts: 88
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From: Azusa California
Thanks - more info
Thanks everyone who answered. I found the following:
http://www.corvettefever.com/howto/1...nifold_repair/
Which seems to describe my symptoms exactly (runs rough cold at first, sounds like a lifter, gets worse )
I might stethoscope it, but I will take it to a shop to do the heavy stuff...
Thanks
Steve
http://www.corvettefever.com/howto/1...nifold_repair/
Which seems to describe my symptoms exactly (runs rough cold at first, sounds like a lifter, gets worse )
I might stethoscope it, but I will take it to a shop to do the heavy stuff...
Thanks
Steve
Burning Brakes
Joined: Feb 2004
Posts: 758
Likes: 14
From: Ville de la Baie Quebec. A winner is just a loser who tried again.
Do the stethescope thing for sure, they are cheap to buy and incredibly accurate for pinpointing funny sounds. Even if your not the one doing the repairs you will be well informed when talking to the mechanic. If you haven't done so already, jack the car up a good 15inchs and inspect for anything that comes in contact with the exhaust, ex. park brake cables.... Good luck
