MTFCA Forum

Went out for a ride tonight and started smelling antifreeze.
Got home and have a leak in head between plug#4 and back of head in round embossed area.
Water spraying out of round embossed area.
Is this a freeze plug area?
Any help appreciated.
Thanks
Rick S.

Pictures would help Rick.

Hank

Pictures of area of concern.

That’s one of 4 pipe thread holes, used for priming cups if needed. Typical to just plug with pipe plug. Yours may need drilling out an old rusted plug or bolt that may have been used.

Thanks Dan
Will check it out in morning and see if a pipe plug will do the fix.
I don't remember a pipe plug in this area
But the memory is not as good as it was once was.

Looks like a typical freeze plug to me. Probably will find that the center is rusted thru. Might get lucky and have a nickel fit in there

Either as Kevin states or a standing boss during the internal core support at casting time. These were a steel type pin which in the long term corrode away. If it is, simple fix by drilling out a small hole using a brass 10/32 brass screw with red Loc-Tite. Sand head off and touch up with paint.

Hope this Helps,

Hank

Kevin

Tend to agree on that, a freeze plug there. Interesting place, my W-R head could have used a freeze plug in that spot. If you look close on mine, a long run of braze is covering a long freeze crack aside the nameplate boss!

Thanks guys for all the info.
Picked up a 1/8" pipe plug and it screws in easily. A little loose until no threads showing.
Any recommendations for sealing plug into head?
Thanks
Rick

What’s showing in the picture IS a “freeze plug”. There are multiple DIFFERENT Waukesha heads. The one pictured uses a freeze plug there.

After further investigation Adam is right a freeze plug it is.
Previous owner of head must have put a pipe plug in or filled center of freeze plug due to previous leak.
Now what is my best option and how to do proper repair.
And where to get correct freeze plug

Some auto parts stores may still have them. What size is it? You could for now, clean it and seal with something like JB weld. Might want to put something like a screw in the hole to bridge the gap for now if you want to do a temp repair. It might be the same size as the T welch or freeze plug.

Drill it out & tap to the appropriate sized pipe plug, apply sealer - done.

Old freeze plug out and area cleaned up ready for the new one.
Thanks to Hank and the MTFCA for all your help.
Rick

Is that what the core hole looks like without the plug ?????

I’ve got one of those heads with that freeze plug boss and have been thinking of re-machining it for a hot water pickup for adding a heater core.

Steve
Yes that is what the core hole looks like without the plug.

Thanks for the reply !

I've got the early priming cup head on our '19 Centerdoor - now I'll have to go look !

You have to be somewhat vigilant with pipe plugs and threads some are running threads referred to as straight threads and some are interference or tapered. Many female threads are straight and usually a tapered plug is inserted to cause an interference fit. If you insert a straight thread plug in to a straight thread casting it will not fit tight as there is no interference. Pipe plugs come in two forms straight and tapered some seat by bottoming out and some by interference.
A tapered plug will seal in a straight casting and a straight plug will seal in a tapered casting, but a straight plug will not seal in a straight casting, other than where designed to seal by bottoming out. So don't take any pipe thread or plug for granted they may be tapered or straight.

If freeze plugs actually worked, that would be a good place for one. I have 3 WR heads like Dan posted and mine do not have a plug there. Getting very hard to find one without freeze cracks. I still like telling about the “perfect” one I bought off the west coast. I knew there was a problem before I lifted it outa the box. I measured 39” !! of crappy weld and braze on the top
of the head, with a heavy paint job over it. That one cost me $40 bucks to return, but at least I got most my money back.
If looking for one, asK for good pictures deep inside the front water outlet.

Dropacent wrote: ↑

Fri Sep 25, 2020 3:20 pm

If freeze plugs actually worked, that would be a good place for one. I have 3 WR heads like Dan posted and mine do not have a plug there. Getting very hard to find one without freeze cracks. I still like telling about the “perfect” one I bought off the west coast. I knew there was a problem before I lifted it outa the box. I measured 39” !! of crappy weld and braze on the top
of the head, with a heavy paint job over it. That one cost me $40 bucks to return, but at least I got most my money back.
If looking for one, asK for good pictures deep inside the front water outlet.

Tim,

The term "freeze plug" is something of a misnomer. Probably just a slang term. They really have nothing to do with preventing freeze cracks, which is why as you state, they don't work to prevent freeze cracks. They are just a cheap way of blocking off the holes that were designed into the pattern/casting and were used for access to support the core.

Thanks Jerry, I was aware of that. I use a larger size on our Rajo oil gauges, and they are getting tough to find. For fun, next time someone takes a trip to an auto parts store, ask for a Welch plug. Or a core plug. Or a freeze plug. Blank stares.
As for the WR head, the one shown is right in line with the core wires. They likely started making the cores differently.

I went in to my favorite parts store and ordered 6 Welch plugs and my friend behind the counter for 27 years had never seen them before.