My Willys 3A and 3B Community
TECH FAQ SECTIONS => Engine compartment => Topic started by: Andrew on October 06, 2025, 09:56:50 PM
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I need to replace a flat disc type freeze plug in a go-devil L Head motor. ANY suggestions on installing the new disc will be greatly appreciated.
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This is something I've never done. I've always let the machine shop take care of that before I pick up the block.
However, there's a ton of articles and videos on the net. I'd read a bit and watch a few different videos to see if there's a central technique that they all use or if one or another shares a useful technique.
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Rus: Yes, I have watched some of those how-to videos. The go-divil uses a slightly convex flat plug rather than a shallow cup plug as shown in the videos. I have ordered a set of the flat plugs and if no instructions are included I will trying to call the vendor for installation procedures. I do have one of the Dorman rubber expansion plugs if all else fails, but I question how long one of those might last. I only have the right side rear plug to replace in a rebuilt motor already installed. I ddn't discover its failure until I started to put antifreeze in it. Somehow/somewhere/sometime it had been hit with an abrasive disc/wheel that reduced the center point of the disc enouth to leak but not show when painted over. Reminds me of an unfortunate Jeep adage, "if it doesn't leak, it isn't a Jeep". I'm trying for just an occasional drip of something; not enough for epa to cause a problem.
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Just did some schooling for myself. That plug on the right (just above the starter?) is apparently the most common to fail. You may find a bunch of crud that will need cleaning out. Definitely flush it.
The plug apparently goes in concave out and after inserting (with something similar to a large socket), you seat it by hitting the center to spread it out. Sound about right?
(I used this method to seal the "cover and tube" on the bottom of the steering gear housing; push it in and smack it to spread it out. I didn't realize the freeze plugs were the same shape.)
I noticed some were suggesting using a sealant to assist as the lip on the seat can also be pitted. On the 2A Forum, one post suggested Indian Head sealant.
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New flat disc freeze plug installed with Permatax #3 (old & very thick) used as a sealant. Everything seemed to go right. Will wait a few days before adding coolant. With a 4pound radiator cap there shouldn't be enough pressure to cause it to pop out.
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Sounds like a plan. Hope that seals it up for many miles to come.