Since this seems to be coming up a lot lately I took some pictures of how I do it. Out of 10+ motors I have only had one leak (previous owner installed plugs and pried them out leaving some pretty nasty grooves).

Get yourself some 20mm freeze (expansion) plugs, I use napa because they seem to always have them in stock. part #381-2151 They should run you about $2.



Clean the ports in the housings well, and check for burrs, or irregularities. A fine grit sandpaper and your finger will smooth out any imperfections quite nicely.

Acquire a suitable installation driver tool, I use a craftsman 6in 3/8 drive socket extension.



A light coat of rtv will act as a lubricant for install and as a sealing agent once they are in.



With a hammer and your socket extension (or other appropriately sized tool) drive them in square to the housing, and just below the surface.



Clean up the errant rtv, and put it all back together. I usually let them cure for a few hours before re-assembly, and overnight before running.




Isaac

 

nice writeup Isaac! i don't think it gets any better than that on an install of the freeze plugs! if you want i can sticky this.

 

Do with it what you please

Isaac

 

Lol perfect timing. I'm trying to find freeze plugs local. Thank you for the part number. I'll see if napa has them in stock hopefully.

 

O'Reilly had the steel ones in stock - I ordered brass ones, on the premise that they'd be less likely to mung the aluminum should I decide to take them back out later.

 

thread is stuck!

 

Silly question, but are the plugs the same size for 12A housings? I only ask because the pictures show a 13B.

 

Yes, all 12a and 13b are 20mm.


Isaac

 

How much of the block would I have to drain in order to take off the manifold without coolant spilling everywhere?

 

About half, drain the radiator halfway first, then use the drain plug on the center iron, drivers side, just above the oil pan. The best reason for freeze plugs IMO is to be able to take the manifold off without spilling any coolant.

Isaac

 

Yeah, that's what I was thinking too. The coolant passages going into the intake manifold are only there to heat it up faster in the winter, right? How much of an effect does blocking them off have on cold weather starts, even if I keep my choke?

 

We always forget about the ACV port, don't we?

 

I have a block-off plate for the ACV, and since I'd be installing a new intake gasket anyway, I'd be making absolutely sure that I'm getting the right one. Unless I'm missing something obvious...?

 

oooooh i just love that you cant make a new thread till you have 20 posts... it has kept me from posting on this site for QUITE SOME TIME NOW!

 

how reversible is this process? I'd really like to try freeze plugs and see how it effects cold starts. but is it possible to remove them without doing a rebuild? maybe drill out the center to pull em out?

 

They come out really easy. I just took a screw driver and tapped it on one side of the indented part (not the ring). The plug swiveled and I was able to pull it out with a pair of pliers. Whatever you do, do not put the screwdriver between the plug and the housing.

 

Edit. Nevermind, sorry for the thread revival.