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fieldsdj7 Samba Member

Joined: August 10, 2022 Posts: 81 Location: Florida
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Posted: Tue Nov 04, 2025 3:17 pm Post subject: Engine Knocking/Tapping Noise with Video |
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https://youtube.com/shorts/JfXz--VZBZ4?feature=share
I was doing carb adjustments and spraying carb cleaner around to see if I could find an air leak when all of a sudden the clicking/tapping noise started.
It seems the longer it runs the louder it gets. I thought initially the pulley was rubbing the tin or I dropped a nut or something down there. I checked and all looks good. Any suggestions? |
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Rob Combs Samba Member

Joined: December 30, 2020 Posts: 826 Location: South Bay LA, California
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Posted: Fri Nov 07, 2025 9:45 am Post subject: Re: Engine Knocking/Tapping Noise with Video |
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| Sounds like exhaust sheet metal rattling. |
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vamram  Samba Member

Joined: March 08, 2012 Posts: 8224 Location: NOVA
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Posted: Fri Nov 07, 2025 10:58 am Post subject: Re: Engine Knocking/Tapping Noise with Video |
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Yep, I posted this in your other thread. I think Mr. Combs is correct, sounds like the crankshaft pulley hitting the pulley tin or the fan in the shroud is wobbly and rubbing. _________________ "Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...we hardly knew ye. Sold 2025 for peanuts.
Click to view image
Save the Supers!! |
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Rob Combs Samba Member

Joined: December 30, 2020 Posts: 826 Location: South Bay LA, California
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Posted: Fri Nov 07, 2025 11:24 am Post subject: Re: Engine Knocking/Tapping Noise with Video |
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I had something similar a few days ago. The small part of the sled tin near the thermostat was clanking around in there, as well as the industrial tins.
Putting them under tension helped control the free resonating and quieted them down. |
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Pez  Samba Member

Joined: September 16, 2003 Posts: 655 Location: East Texas
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Posted: Fri Nov 07, 2025 12:58 pm Post subject: Re: Engine Knocking/Tapping Noise with Video |
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That's not a tapping, something rotating is rubbing. Remove the belt and run for a few seconds to rule out the fan rubbing the shroud. If noise is still there double/triple check your crank pulley is not making contact with the tin.
Edit: More I listen to it, it could possibly be a small exhaust leak. Rule out the rubbing possibilities first though. Then check for exhaust leaks. You can use soapy water to check by the way. _________________ Chasing Squirrel's.
1971 Bay Window
1966 Baja |
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Cusser Samba Member

Joined: October 02, 2006 Posts: 33430 Location: Hot Arizona
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Posted: Fri Nov 07, 2025 3:15 pm Post subject: Re: Engine Knocking/Tapping Noise with Video |
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Before the engine gets hot, start the engine and feel for exhaust air with your hand. This way you shouldn't get burned.
Don't forget the heat riser gasket area either. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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whobba Samba Member

Joined: March 19, 2002 Posts: 887
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fieldsdj7 Samba Member

Joined: August 10, 2022 Posts: 81 Location: Florida
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Posted: Sat Nov 08, 2025 5:18 pm Post subject: Re: Engine Knocking/Tapping Noise with Video |
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| Rob Combs wrote: |
| Sounds like exhaust sheet metal rattling. |
I do believe that is what it is. When I push around the tin it stops. |
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Rob Combs Samba Member

Joined: December 30, 2020 Posts: 826 Location: South Bay LA, California
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Posted: Sun Nov 09, 2025 9:07 pm Post subject: Re: Engine Knocking/Tapping Noise with Video |
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Screw it down to something or bend/twist to put it under tension might make it stop.
Adding weight (I know, blasphemy) can do the same thing - maybe a couple rare earth magnets strategically placed - could also help by changing its resonant frequency.
Glad you got it localized and it’s nothing serious! |
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