Ticking Noise from underside
12-31-2018, 02:17 PM
#11
Join Date: Dec 2018
Location: tx
Posts: 1
Sounds Like Cavitation
I don't own a Mustang, but a friend does (in Texas by-the-way) and I briefly listened to this sound on his car last week. The sound immediately rang a bell in my head.
I am an ex-Navy sonar technician, and a former sidescan sonar imaging company owner. The sound I heard from his car sounded exactly what I would expect "cavitation" to sound like. Cavitation is caused when a fluid comes in contact with a rapidly moving object. Without getting too technical, if the energy imparted to the fluid exceeds the fluid's ability to displace based upon it's viscosity, a vacuum "hole" can be torn in the fluid on the trailing edge of the moving object. This vacuum hole will slam shut once it leaves the area, and makes an audible "crackle". In ships, the energy imparted by this "slamming shut" of the vacuum hole actually damages metal propellers, and is loud enough to make the vessel audible for hundreds of miles in some cases.
I'm not a mechanic nor a fluid dynamics expert, but it occurs to me that perhaps a crankshaft counterbalance making contact with oil in a sump could do this assuming very light oil was being used. I suppose the cooling system could also be responsible, but it's hard to imagine some new problem cropping up there what with how well developed that technology is. At any rate, it has something to do with fluid if it's cavitation.
If you want a second opinion on the nature of the noise, a good recording of it presented to a sonar OPERATOR would be better qualified than I to confirm the cavitation hypothesis.
If you guys want to hear what cavitation sounds like on a large, industrial, scale, here is a video.
I am an ex-Navy sonar technician, and a former sidescan sonar imaging company owner. The sound I heard from his car sounded exactly what I would expect "cavitation" to sound like. Cavitation is caused when a fluid comes in contact with a rapidly moving object. Without getting too technical, if the energy imparted to the fluid exceeds the fluid's ability to displace based upon it's viscosity, a vacuum "hole" can be torn in the fluid on the trailing edge of the moving object. This vacuum hole will slam shut once it leaves the area, and makes an audible "crackle". In ships, the energy imparted by this "slamming shut" of the vacuum hole actually damages metal propellers, and is loud enough to make the vessel audible for hundreds of miles in some cases.
I'm not a mechanic nor a fluid dynamics expert, but it occurs to me that perhaps a crankshaft counterbalance making contact with oil in a sump could do this assuming very light oil was being used. I suppose the cooling system could also be responsible, but it's hard to imagine some new problem cropping up there what with how well developed that technology is. At any rate, it has something to do with fluid if it's cavitation.
If you want a second opinion on the nature of the noise, a good recording of it presented to a sonar OPERATOR would be better qualified than I to confirm the cavitation hypothesis.
If you guys want to hear what cavitation sounds like on a large, industrial, scale, here is a video.
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