Engine Experts: What is this noise?
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 1,028
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From: La Jolla, CA
Re: Engine Experts: What is this noise? (vettman10)
I just listened to the engine with a stethoscope and metal probe. I heard lots of clicking/ticking all over the place, but could not hear a clear difference between cylinders (sound transmission blurring it all together?).
What is interesting is that the ticking/knocking noise sounds loudest from underneath the car. Could be transmitted sound, I don't know.
If I let the car sit for about 30 minutes after warming oil temp to 200+, then start it up, there is little noise. If I then rev the engine to around 3000 RPM for a few seconds, the ticking/knocking then returns loudly, and keeps on ticking (does not appear to diminish once started).
C5-TECH- do you have any more information on the O-ring/aeration TSB, specifically what is ticking (lifters? oil pump?).
What is interesting is that the ticking/knocking noise sounds loudest from underneath the car. Could be transmitted sound, I don't know.
If I let the car sit for about 30 minutes after warming oil temp to 200+, then start it up, there is little noise. If I then rev the engine to around 3000 RPM for a few seconds, the ticking/knocking then returns loudly, and keeps on ticking (does not appear to diminish once started).
C5-TECH- do you have any more information on the O-ring/aeration TSB, specifically what is ticking (lifters? oil pump?).
Pro
Joined: Mar 2001
Posts: 512
Likes: 19
From: Greensboro NC
Re: Engine Experts: What is this noise? (johnC5)
What's your oil pressure at idle when the oil is hot? Aeration seems to be evident by low oil pressure. If indeed the o-ring on the oil pump is cut and your oil is getting air in it, that's not good for your engine. One way to tell, as I understand it, is to look at the oil as the engine is running under your valve covers (cover has to be removed and will make a mess). As I understand it, you will see airbubbles in the oil there. Call Andy at A&A Corvette (forum vendor) and ask him about that. He has first hand experience with a cut o-ring and can better describe what to look for.
Frank
Frank
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 1,028
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From: La Jolla, CA
Re: Engine Experts: What is this noise? (QwikSilvr)
What's your oil pressure at idle when the oil is hot? Aeration seems to be evident by low oil pressure. If indeed the o-ring on the oil pump is cut and your oil is getting air in it, that's not good for your engine. One way to tell, as I understand it, is to look at the oil as the engine is running under your valve covers (cover has to be removed and will make a mess). As I understand it, you will see airbubbles in the oil there. Call Andy at A&A Corvette (forum vendor) and ask him about that. He has first hand experience with a cut o-ring and can better describe what to look for.
Frank
Frank
If there is aeration wouldn't all lifters be affected? The sound appears to be one element (if it's a lifter, it sounds like just one). Is is possible that just one lifter is getting aerated oil (something stuck in a galley?)?
Does Andy have internet access? Can he watch the video?
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 1,028
Likes: 0
From: La Jolla, CA
Re: Engine Experts: What is this noise? (QwikSilvr)
What's your oil pressure at idle when the oil is hot? Aeration seems to be evident by low oil pressure. If indeed the o-ring on the oil pump is cut and your oil is getting air in it, that's not good for your engine. One way to tell, as I understand it, is to look at the oil as the engine is running under your valve covers (cover has to be removed and will make a mess). As I understand it, you will see airbubbles in the oil there. Call Andy at A&A Corvette (forum vendor) and ask him about that. He has first hand experience with a cut o-ring and can better describe what to look for.
Frank
Frank
cold, idle: 46, peak 70+
hot,idle : 33, peak 64
Oil filter is a UPF-44, oil is Mobil 1 5w-30 (not SuperSyn).
Can hear sound at cold startup from underneath the car. Appears to get louder as engine warms up.
Pro
Joined: Mar 2001
Posts: 512
Likes: 19
From: Greensboro NC
Re: Engine Experts: What is this noise? (johnC5)
John, your oil pressure looks ok, but I'd still call Andy to discuss the symptoms of aeration so you can eliminate that totally. You can find him in the vendor section. Good luck....
Frank
Frank
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 1,028
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From: La Jolla, CA
Re: Engine Experts: What is this noise? (QwikSilvr)
John, your oil pressure looks ok, but I'd still call Andy to discuss the symptoms of aeration so you can eliminate that totally. You can find him in the vendor section. Good luck....
Frank
Frank
Thread Starter
Burning Brakes
Joined: Jun 1999
Posts: 1,028
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From: La Jolla, CA
Noise Source Identified
The problem has been solved: http://forums.corvetteforum.com/zerothread?id=503410 .
