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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Thu Nov 06, 2025 1:59 pm Post subject: Small hole in the bottom of crank case |
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| Looks like a possible flaw in the casting that held up for a few years. The question is, can I use JB weld? The motor is running fine. I have a pick stuck in it to locate and it seems round and small. |
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my3bugs Samba Member
Joined: June 18, 2003 Posts: 950 Location: Moreno Valley
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Posted: Thu Nov 06, 2025 2:10 pm Post subject: Re: Small hole in the bottom of crank case |
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| does it leak there ? |
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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Thu Nov 06, 2025 2:52 pm Post subject: Re: Small hole in the bottom of crank case |
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| Yes it's leaking quite good. |
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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Thu Nov 06, 2025 3:15 pm Post subject: Re: Small hole in the bottom of crank case |
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Plugged with a small pic. I guess I can JB it unless someone has a better idea. |
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crofty Judas of the North

Joined: August 09, 2000 Posts: 19910 Location: Land of Whine and Phonies
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Posted: Thu Nov 06, 2025 3:19 pm Post subject: Re: Small hole in the bottom of crank case |
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jb might work but id assume you'd have to drain and clean well so there was no oil to mess up the bonding? _________________ Your Vanagon sucks, Stop waving at me.
| HamburgerBrad wrote: |
I slept on crofty's tent once. I passed out drunk from two bottles of Everett's brother's wine. |
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my3bugs Samba Member
Joined: June 18, 2003 Posts: 950 Location: Moreno Valley
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Posted: Thu Nov 06, 2025 3:35 pm Post subject: Re: Small hole in the bottom of crank case |
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JB weld gets bubble gum soft when hot , not sure thats the best product here . it might work ?
i used it on some lanterns and when it got hot it just lets go . but it wasent deep in a hole like this . i wonder about when you glue it up maybe find a small nail or something to tap in the hole , i duno just thinking out loud . |
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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Thu Nov 06, 2025 3:49 pm Post subject: Re: Small hole in the bottom of crank case |
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| It's drained, hitting it with a powered brush. I'll look into a better product to use. It is a weird hole between fins and small. We heard an unexplained BANG last week but I don't know how anything could get between the fins. But there's another bottom end in the garage if this doesn't work. If anyone knows a good product to patch this thang I will try it. |
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Eric&Barb Samba Member

Joined: September 19, 2004 Posts: 26267 Location: Olympia Wash Rinse & Repeat
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Posted: Thu Nov 06, 2025 5:10 pm Post subject: Re: Small hole in the bottom of crank case |
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Personally would drill the hole to at least a size for a 8mm thread. Counter bore the fins to make way for a hex head bolt to fit. Then use a copper washer to seal between the bolt and case. _________________ In Stereo, Where Available! |
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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Thu Nov 06, 2025 6:25 pm Post subject: Re: Small hole in the bottom of crank case |
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Thanks. That sounds good but the washer is maybe. I'm thinking threaded and hi temp epoxy.
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BonTonRoulet Samba Member
Joined: September 29, 2020 Posts: 486 Location: Mississippi
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Posted: Thu Nov 06, 2025 8:53 pm Post subject: Re: Small hole in the bottom of crank case |
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There are several places on an air cooled Porsche 911 engine where JB Weld is the commonly accepted compound to prevent oil leaks such as the chain tensioner pivot bosses that are a press fit in the chain tensioner cases. _________________ Never argue with an Idiot. They'll only bring you down to their level and beat you with experience. |
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Who.Me? Samba Member

Joined: July 14, 2014 Posts: 2598 Location: UK (South)
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Posted: Fri Nov 07, 2025 2:25 am Post subject: Re: Small hole in the bottom of crank case |
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I'd go with something similar to Eric&Barb's solution, but use a grub screw with thread sealant on the thread (e.g. loctite 577) rather than a bolt and washer. No need to make the area around the hole flush with the case to take a washer then.
The concern might be whether that's actually a corrosion hole, in which case the area around it may be thin. _________________ Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786 |
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Bobs67vwagen Samba Member
Joined: March 27, 2005 Posts: 873 Location: Eastern north carolina
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Posted: Fri Nov 07, 2025 4:16 am Post subject: Re: Small hole in the bottom of crank case |
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| I would try a sheet metal screw just a tad bigger than the hole with high temp sealant. |
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69aircooled Samba Member

Joined: August 04, 2004 Posts: 263 Location: North Carolina
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Posted: Fri Nov 07, 2025 6:36 am Post subject: Re: Small hole in the bottom of crank case |
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JB Weld should work to repair a small hole/void on the engine case. There may be other products as well. The problem is lots of time these old cases will basically rot from the inside out due to condensation building up on the inside. Over time, years, that can build up enough to settle to the bottom under the oil and slowly eat away at the magnesium alloy.
You may want to drain your oil and pull the screen/cover and inspect the inside surface. A bore scope can be very helpful in making a decision on the path to go. |
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Lind Samba Member

Joined: November 06, 2000 Posts: 10269 Location: idaho
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Posted: Fri Nov 07, 2025 8:00 am Post subject: Re: Small hole in the bottom of crank case |
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| 69aircooled wrote: |
JB Weld should work to repair a small hole/void on the engine case. There may be other products as well. The problem is lots of time these old cases will basically rot from the inside out due to condensation building up on the inside. Over time, years, that can build up enough to settle to the bottom under the oil and slowly eat away at the magnesium alloy.
You may want to drain your oil and pull the screen/cover and inspect the inside surface. A bore scope can be very helpful in making a decision on the path to go. |
I was thinking this exact thing. The inside bottom of that case probably has extensive corrosion, and this is just the one place it has come all the way through. I doubt there will be enough meat to drill and tap into it in that area. _________________ .
Wanted:
Idaho VW license plate frames or other dealership items.
VWoA literature and early dealership or distributor literature/pictures/information
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Fat Freddie Samba Member
Joined: May 25, 2011 Posts: 15
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Posted: Fri Nov 07, 2025 4:48 pm Post subject: Re: Small hole in the bottom of crank case |
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| Thanks everyone. It's JB for now. I'll see what happens tomorrow. It does seem like it could be corrosion. I can still drill and thread if it doesn't work. |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 36324 Location: Conejo Valley, CA
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Posted: Fri Nov 07, 2025 4:52 pm Post subject: Re: Small hole in the bottom of crank case |
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Maybe a J-B Weld smothered pop rivet could bite the hole and not need tapping? _________________ Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1663 Location: S.W. MI
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Posted: Sat Nov 08, 2025 6:10 am Post subject: Re: Small hole in the bottom of crank case |
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Drill it to 1/4" then tap for 1/16 NPT pipe plug. _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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BarryL  Samba Member

Joined: November 01, 2004 Posts: 15452 Location: Casa de Oro, California
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Posted: Sat Nov 08, 2025 6:42 pm Post subject: Re: Small hole in the bottom of crank case |
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| Is it on the side of the engine that the thermostat bracket is on? |
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