Cool/Heat: Expansion plug replacement

[Neal in NM]

In August of ‘18 I installed my rebuilt 246 Commander engine in my ‘48 M-16. Due to surgery in September of ‘18 I was unable to work on the truck in till this year. I started it today and it came up to temperature several times, I even drove it down the road! While it was in the driveway (thank goodness), the top rear freeze plug popped out and dumped all the coolant. I was able to shut the engine down immediately.
My first reaction was oh no I’m going to have to pull the engine. After cleaning up my tools I removed the tranny cover and found the errant freeze plug. My plan (instead of removing the engine) is to cut a hole in the firewall to access the expansion plug hole. Looking at the plug that popped out, I believe I didn’t flatten it out enough.

Has anyone done this before?
Any recommendations?

Thanks, Neal

[skyway]

Have never attempted that particular job but as regards cutting your hole, if you can use a hole saw a neat trick is that once the
saw has scribed its line cant the saw so that it'll cut thru but leave the center still attached. That way you can pry it out of the way to
access the job & then bend it back when finished. Smear on a bit of sealer & no one will ever know!

[StudeRich]

That sounds very doable Neal, the ONLY time I have heard of someone doing that, was when Dad had himself bought a '41 Buick Roadmaster 4 Door Sedan on a trade-in from a New Stude. buyer.

When cleaning it up to flip it, Dad had a friend cut a hole in the firewall to excess a rusted out Core Plug in the back of the Big Straight Eight, Dual Carb. Buick.

[RadioRoy]

I did just this on my 51 Champion car some 40 years ago. You do NOT need to cut a big hole in the firewall if you think outside the box. Here's how I did it. The Champion car firewall is pretty close to the rear of the engine block.

Tools needed:
-A LONG jobbers length drill bit around 1/4" or so and at least 12" = 18" long
-drill motor
-large right angle Allen wrench slightly smaller diameter than the drill bit
-long drift punch slightly smaller diameter than the drill bit
-hammer
-expansion plug
-appropriate goop for the edge of the expansion plug

Pull back the floor mat and firewall insulation.
Determine the position of the expansion plug relative to the firewall inside the cab.
Drill a 1/4" hole through the firewall into the expansion plug, as close to the center of the plug as possible.
From under the hood, hook the short end of the Allen wrench into the hole in the expansion plug and use the wrench to pop the plug out.
Place the new plug in place after cleaning the hole in the engine and gooping up the plug.
From inside the cab, use the long drift punch to walk around the edge of the plug and force the plug into place.

The only hole you need in the floor is the little 1/4" drill hole. Easy to patch.

Actually, since your plug fell out, two thirds of the job is already done for you. You can do it with a short drill and a long punch.

The whole point is to think it through before doing it. The first solution that comes to mind is not necessarily the best solution.

[RadioRoy]

OK. I took my own advice and thought about it some more.
I am not familiar with how the engine sits in an M series. If there is enough room to get your hands between the block and the firewall, you can buy one of those brass plugs with a nut in the middle that expand when you turn the nut. You can do it all from under the hood if there is enough room.

The plug looks like the one in this eBay auction. Choose the correct size.

https://www.ebay.com/itm/Engine-Expa...AAAOSwgh5bmSs6

[Charlie D]

Neal,

I think if you put the words "expansion plug" in the search box one of the posts is my post dated 10/25/17. It talks about the problem I ran into trying to use a Dorman expansion plug. It might help you a little.

Charlie D.

[StudeRich]

They HAVE to be kidding Roy, $28.00 for ONE adjustable Dorman Core Plug, now probably made in China?
Are they made of GOLD?

[doofus]

Yes, made in china. and you will need a thin, old fashion tappet wrench to hold the body while you tighten it. check with your FLAPS, they can order them in singles probably cheaper. Luck Doofus

[bensherb]

They HAVE to be kidding Roy, $28.00 for ONE adjustable Dorman Core Plug, now probably made in China?
Are they made of GOLD?

My sentiments exactly, welcome to post 2007 America! When I retired in 1998 I was set and doing very well, now I'm broke and scraping by. Who expected the price of most everything (except the price controlled stuff they base inflation numbers on) to at least triple in just a few years. Thank god for the 99.9 cent store, even though half the stuff in it just went up 50%. I guess they'll have to change the name.

If you search that same plug on ebay, They run from $8 to $121. Most are between $22 and $35.

Check out what they're asking for lug studs and nuts these days. It's no wonder a $3,500 car costs $35,000.
Stud, https://www.carid.com/studebaker-lug...YaAgPrEALw_wcB
Nut, https://www.ebay.com/i/233212426701?...4aAq-LEALw_wcB

[RadioRoy]

They HAVE to be kidding Roy, $28.00 for ONE adjustable Dorman Core Plug, now probably made in China?
Are they made of GOLD?

They are kind of gold-ish colored.

[nvonada]

On my Champion I lost the plug on the back of the block. Twice. I found I was able to get to it by lowering the back of the engine. I had to disconnect exhaust, driveshaft, oil pressure line, etc. But then I could unbolt the rear crossmember and lower the engine just enough to get to that plug though the access hole in the floorboard.
http://stude.vonadatech.com/wp/freeze-plug-leak/

Nathan

[Charlie D]

Nathan,
I enjoyed your web site and have book marked it for further reading.
Charlie D.

[Neal in NM]

Update. After careful measurements, I used a 2” hole saw on the firewall. I could see the expansion plug hole when the transmission cover was removed but, couldn’t get a decent angle to punch the Welch plug. I used some Indian head sealant and gave it a few hard punches. While I was at it, I repunched all the other expansion plugs I could reach. I found a hole cover at the oldest “FLAPS” in town. It looks ok but, I kept the hole from the firewall to probably weld in later.